Overview on the history of organofluorine chemistry from the viewpoint of material industry

PubMed Central

Okazoe, Takashi

2009-01-01

Fluorine (from “le fluor”, meaning “to flow”) is a second row element of Group 17 in the periodic table. When bound to carbon it forms the strongest bond in organic chemistry to give organofluorine compounds. The scientific field treating them, organofluorine chemistry, started before elemental fluorine itself was isolated. Applying the fruits in academia, industrial organofluorine chemistry has developed over 80 years via dramatic changes during World War II. Nowadays, it provides various materials essential for our society. Recently, it utilizes elemental fluorine itself as a reagent for the introduction of fluorine atoms to organic molecules in leading-edge industries. This paper overviews the historical development of organofluorine chemistry especially from the viewpoint of material industry. PMID:19838009

Fused thiophene and its periphery fluorinated substitution derivatives: a theoretical study for organic semiconductors

NASA Astrophysics Data System (ADS)

Wei, Hui-Ling; Shi, Ya-Rui; Liu, Yu-Fang

2015-06-01

A series of phenyl end-capped derivatives of benzo[d,d‧]thieno[3,2-b4,5- b‧]dithiophene (BTDT) with periphery-fluorinated substitutions (PFS) were systematically investigated by using density functional theory (DFT) combined with the Marcus-Hush electron transfer theory. The substituting effects of PFS were discussed. Compared with the original compounds, (i) the PFS compounds have a relatively higher efficiency of charge transport, lower barriers of electron injection, and larger HOMO-LUMO gaps; (ii) the air-stability and the device performance are enhanced by PFS; and (iii) the HOMO-LUMO transitions in the absorption spectrum of the PFS compounds show an obvious blue-shift trend. The perfluorophenylbisbenzo[d, d‧]thieno[3,2-b4,5-b‧]dithiophene (BpF-BTDT) is found to be the most stable and most effective compound in charge transport among the investigated compounds, and it is suggested as an ambipolar semiconducting material. The results of electronic coupling of the bisbenzo[d, d‧]thieno[3,2-b 4,5- b‧]dithiophene (BBTDT) derivatives show that the orbital interaction is mainly contributed by the neighboring molecule in the two dimensional (2D) layer. The PFS compounds have lower oxidization potential, ionization potential, and electron affinity values than the corresponding original ones, which suggest that fluorination can enhance the performance of the thiophene-based organic solar cells. These findings provide a better understanding of the PFS effects on organic semiconductors and may help to design high-performance semiconductor materials.

Natural and engineered biosynthesis of fluorinated natural products.

PubMed

Walker, Mark C; Chang, Michelle C Y

2014-09-21

Both natural products and synthetic organofluorines play important roles in the discovery and design of pharmaceuticals. The combination of these two classes of molecules has the potential to be useful in the ongoing search for new bioactive compounds but our ability to produce site-selectively fluorinated natural products remains limited by challenges in compatibility between their high structural complexity and current methods for fluorination. Living systems provide an alternative route to chemical fluorination and could enable the production of organofluorine natural products through synthetic biology approaches. While the identification of biogenic organofluorines has been limited, the study of the native organisms and enzymes that utilize these compounds can help to guide efforts to engineer the incorporation of this unusual element into complex pharmacologically active natural products. This review covers recent advances in understanding both natural and engineered production of organofluorine natural products.

The Photocatalytic Destruction of Volatile Organic Compounds in Water

DTIC Science & Technology

1991-12-10

some common oxidants. It can be seen that the hydroxyl radical is only second to the fluorine ion in oxidation potential. 5 Table 2.1 Dissociation...Potential of Oxidants (Bernardin, 1991) Relative Oxidation Oxidative Power, Chlorine = 1 Species Potential (volts) 2.23 Fluorine 3.03 2.06 Hydroxyl... varnishes . It is used as a universal degreaser, in drycleaning, and in the manufacture of organic chemicals. On military bases it is used as a universal

Perfluoroalkyl acids: recent research highlights

EPA Science Inventory

Perfluorinated compounds are organic chemicals in which all hydrogen molecules of the carbon-chain are substituted by fluorine molecules. Generally, there are two types of perfluorinated compounds, the perfluoroalkanes that are primarily used clinically for oxygenation and respir...

[Current trends in fluorine research].

PubMed

Machoy-Mokrzyńska, Anna; Machoy, Zygmunt

2006-01-01

Current topics in fluorine research are presented with emphasis on findings by researchers in Szczecin and Poland, as well as in the world. Reports are cited on the distribution of fluorine compounds in the environment, routes of penetration into living organisms, and analytical methods for the quantitative determinations of fluorine content in air, water, soil, and foods. Important contributions have been made by Polish researchers on the role and patterns of fluorides in body fluids, soft and hard tissues, which remain in direct relationship to accumulation and elimination of fluorine. So far, comprehensive studies on mutagenic effects of fluorine and its potential role in bone neoplasms, Down syndrome, and other genetic disorders have not been carried out in Poland. Worthy of mention are reports on mechanisms of action of fluorine compounds on the cellular and subcellular level. Finally, two achievements of recent years in the field of fluorine research are discussed briefly. The first is concerned with the use in dentistry of chemical analysis for studying mineral reconstruction of teeth throughout the lifetime of an individual. The second is in the field of medicine where molecular modeling has been applied to explain the mechanism of action of aluminofluoride complexes (AlFx) as a messenger of false information during protein biosynthesis and their apparent role in the etiology of Alzheimer's disease.

Ionic liquids as an electrolyte for the electro synthesis of organic compounds.

PubMed

Kathiresan, Murugavel; Velayutham, David

2015-12-25

The use of ionic liquids (ILs) as a solvent and an electrolyte for electro organic synthesis has been reviewed. To date several ILs exist, however the ILs based on tetraalkylammonium, pyrrolidinium, piperidinium and imidazolium cations with BF4(-), PF6(-), and TFSI anions have been widely used and explored the most. Electro organic synthesis in ionic liquid media leading to the synthesis of a wide range of organic compounds has been discussed. Anodic oxidation or cathodic reduction will generate radical cation or anion intermediates, respectively. These radicals can undergo self coupling or coupling with other molecules yielding organic compounds of interest. The cation of the IL is known to stabilize the radical anion extensively. This stabilization effect has a specific impact on the electrochemical CO2 reduction and coupling to various organics. The relative stability of the intermediates in IL leads to the formation of specific products in higher yields. Electrochemical reduction of imidazolium or thiazolium based ILs generates N-heterocyclic carbenes that have been shown to catalyze a wide range of base or nucleophile catalyzed organic reactions in IL media, an aspect that falls into the category of organocatalysis. Electrochemical fluorination or selective electrochemical fluorination is another fascinating area that delivers selectively fluorinated organic products in Et3N·nHF or Et4NF·nHF adducts (IL) via anodic oxidation. Oxidative polymerization in ILs has been explored the most; although morphological changes were observed compared to the conventional methods, polymers were obtained in good yields and in some cases ILs were used as dopants to improve the desired properties.

21 CFR 170.45 - Fluorine-containing compounds.

Code of Federal Regulations, 2010 CFR

2010-04-01

... § 170.45 Fluorine-containing compounds. The Commissioner of Food and Drugs has concluded that it is in the interest of the public health to limit the addition of fluorine compounds to foods (a) to that... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Fluorine-containing compounds. 170.45 Section 170...

Determination of size and sign of hetero-nuclear coupling constants from 2D 19F-13C correlation spectra.

PubMed

Ampt, Kirsten A M; Aspers, Ruud L E G; Dvortsak, Peter; van der Werf, Ramon M; Wijmenga, Sybren S; Jaeger, Martin

2012-02-01

Fluorinated organic compounds have become increasingly important within the polymer and the pharmaceutical industry as well as for clinical applications. For the structural elucidation of such compounds, NMR experiments with fluorine detection are of great value due to the favorable NMR properties of the fluorine nucleus. For the investigation of three fluorinated compounds, triple resonance 2D HSQC and HMBC experiments were adopted to fluorine detection with carbon and/or proton decoupling to yield F-C, F-C{H}, F-C{C(acq)} and F-C{H,C(acq)} variants. Analysis of E.COSY type cross-peak patterns in the F-C correlation spectra led, apart from the chemical shift assignments, to determination of size and signs of the J(CH), J(CF), and J(HF) coupling constants. In addition, the fully coupled F-C HMQC spectrum of steroid 1 was interpreted in terms of E.COSY type patterns. This example shows how coupling constants due to different nuclei can be determined together with their relative signs from a single spectrum. The analysis of cross-peak patterns, as presented here, not only provides relatively straightforward routes to the determination of size and sign of hetero-nuclear J-couplings in fluorinated compounds, it also provides new and easy ways for the determination of residual dipolar couplings and thus for structure elucidation. The examples and results presented in this study may contribute to a better interpretation and understanding of various F-C correlation experiments and thereby stimulate their utilization. Copyright © 2011 Elsevier Inc. All rights reserved.

Synthetic biology approaches to fluorinated polyketides

PubMed Central

Thuronyi, Benjamin W.; Chang, Michelle C. Y.

2016-01-01

Conspectus The catalytic diversity of living systems offers a broad range of opportunities for developing new methods to produce small molecule targets such as fuels, materials, and pharmaceuticals. In addition to providing cost-effective and renewable methods for large-scale commercial processes, the exploration of the unusual chemical phenotypes found in living organisms can also enable the expansion of chemical space for discovery of novel function by combining orthogonal attributes from both synthetic and biological chemistry. In this context, we have focused on the development of new fluorine chemistry using synthetic biology approaches. While fluorine has become an important feature in compounds of synthetic origin, the scope of biological fluorine chemistry in living systems is limited, with fewer than 20 organofluorine natural products identified to date. In order to expand the diversity of biosynthetically accessible organofluorines, we have begun to develop methods for the site-selective introduction of fluorine into complex natural products by engineering biosynthetic machinery to incorporate fluorinated building blocks. To gain insight into how both enzyme active sites and metabolic pathways can be evolved to manage and select for fluorinated compounds, we have studied one of the only characterized natural hosts for organofluorine biosynthesis, the soil microbe Streptomyces cattleya. This information provides a template for designing engineered organofluorine enzymes, pathways, and hosts and has allowed us to initiate construction of enzymatic and cellular pathways for the production of fluorinated polyketides. PMID:25719427

Boron compounds as anion binding agents for nonaqueous battery electrolytes

DOEpatents

Lee, Hung Sui; Yang, Xia-Oing; McBreen, James; Xiang, Caili

2000-02-08

Novel fluorinated boron-based compounds which act as anion receptors in non-aqueous battery electrolytes are provided. When added to non-aqueous battery electrolytes, the fluorinated boron-based compounds of the invention enhance ionic conductivity and cation transference number of non-aqueous electrolytes. The fluorinated boron-based anion receptors include borane and borate compounds bearing different fluorinated alkyl and aryl groups.

Synthesis of carbon-11, fluorine-18, and nitrogen-13 labeled radiotracers for biomedical applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fowler, J.S.; Wolf, A.P.

A number of reviews, many of them recent, have appeared on various aspects of /sup 11/C, /sup 18/F and /sup 13/N-labeled radiotracers. This monograph treats the topic principally from the standpoint of synthetic organic chemistry while keeping in perspective the necessity of integrating the organic chemistry with the design and ultimate application of the radiotracer. Where possible, recent examples from the literature of organic synthesis are introduced to suggest potentially new routes which may be applied to problems in labeling organic molecules with the short-lived positron emitters, carbon-11, fluorine-18, and nitrogen-13. The literature survey of carbon-11, fluorine-18 and nitrogen-13 labeledmore » compounds presented are of particular value to scientists working in this field. Two appendices are also included to provide supplementary general references. A subject index concludes this volume.« less

Biodegradation of fluorinated alkyl substances.

PubMed

Frömel, Tobias; Knepper, Thomas P

2010-01-01

The incorporation of fluorine into organic molecules entails both positive and adverse effects. Although fluorine imparts positive and unique properties such as water-and oil-repellency and chemical stability, adverse effects often pervade members of this compound class. A striking property of long perfluoroalkyl chains is their very pronounced environmental persistence. The present review is the first one designed to summarize recent accomplishments in the field of biodegradation of fluorine-containing surfactants, their metabolites, and structural analogs. The pronounced scientific and public interest in these chemicals has given impetus to undertake numerous degradation studies to assess the sources and origins of different fluorinated analog chemical known to exist in the environment. It was shown that biodegradation plays an important role in understanding how fluorinated substances reach the environment and, once they do, what their fate is. Today, PFOS and PFOA are ubiquitously detected as environmental contaminants. Their prominence as contaminants is mainly due to their extreme persistence, which is linked to their perfluoroalkyl chain length. It appears that desulfonation of a highly fluorinated surfactants can be achieved if an α-situated H atom, in relation to the sulfonate group, is present, at least under sulfur-limiting conditions. Molecules that are less heavily fluorinated can show very complex metabolic behavior, as is the case for fluorotelomer alcohols. These compounds are degraded via different but simultaneous pathways, which produce different stable metabolites, one of which is the respective perfluoroalkanoate (8:2-FTOH is transformed to PFOA). Preliminary screening tests indicate that fluorinated functional groups, such as the trifluoromethoxy group and the p-(trifluoromethyl)phenoxy group, may be useful implementations in novel, environmentally benign fluorosurfactants. More specifically, trifluoromethoxy groups constitute a substitute for those that have been used in the past; this functionality is degradable when it appears in structures that are normally subject to biodegradation. Other compounds tested did not meet this criterion. Interdisciplinary investigations on fluorinated surfactants are still very much needed and will certainly continue during the next many years. For instance, the role of fluorinated polymers in contributing small fluorinated molecules to the environmental burden still has not been fully understood.

[Health effects of fluorine and its compounds].

PubMed

Kono, K

1994-12-01

Fluoride, the ionic form of fluorine, is a natural component of the biosphere and 13th most abundant element in the crust of the earth. It is, therefore, found in a wide range of concentrations in virtually all inanimate and living things. Many trace elements perform a definite function in human metabolism and the question of the value of fluoride, always found in the body, has been raised. Much evidence suggesting that the inclusion of fluoride in drinking water has beneficial as well as adverse effects on human health was obtained. Either alone or in combination with calcium and/or vitamin D, it is used in high daily doses for the treatment of osteoporosis. Although organic fluorine compounds are used in medicine and commerce, the inorganic fluorine compounds are of greater importance toxicologically because they are more readily available. The major pathway of fluoride elimination from the human body is via the kidney. When renal function deteriorates, the ability to excrete fluoride markedly decreases, possibly resulting in greater retention of fluoride in the body. At this point, more research is needed to evaluate the effects of physiological variables on the fluoride metabolism in humans.

Characterization of a Wide Array of Fluorinated Organic Compounds in Contaminated Soils

EPA Science Inventory

Herein we report the results of analyses on the concentrations of perfluorinated compounds (PFCs) and fluorotelomer alcohols (FTOHs) in soils from a site that has been impacted by human activities. Soil samples were collected from several locations that had been impacted and one...

SEPARATION PROCESS FOR PROTACTINIUM AND COMPOUNDS THEREOF

DOEpatents

Van Winkle, A.

1959-07-21

The separation of protactinium from aqueous solutions from its mixtures with thorium, uranium and fission products is described. The process for the separation comprises preparing an ion nitric acid solution containing protactinium in the pentavalent state and contacting the solution with a fluorinated beta diketone, such as trifluoroacetylacetone, either alone or as an organic solvent solution to form a pentavalent protactinium chelate compound. When the organic solvent is present the chelate compound is extracted; otherwise it is separated by filtration.

The biodegradation vs. biotransformation of fluorosubstituted aromatics.

PubMed

Kiel, Martina; Engesser, Karl-Heinrich

2015-09-01

Fluoroaromatics are widely and--in recent years--increasingly used as agrochemicals, starting materials for chemical syntheses and especially pharmaceuticals. This originates from the special properties the carbon-fluorine bond is imposing on organic molecules. Hence, fluoro-substituted compounds more and more are considered to be important potential environmental contaminants. On the other hand, the microbial potentials for their transformation and mineralization have received less attention in comparison to other haloaromatics. Due to the high electronegativity of the fluorine atom, its small size, and the extraordinary strength of the C-F bond, enzymes and mechanisms known to facilitate the degradation of chloro- or bromoarenes are not necessarily equally active with fluoroaromatics. Here, we review the literature on the microbial degradation of ring and side-chain fluorinated aromatic compounds under aerobic and anaerobic conditions, with particular emphasis being placed on the mechanisms of defluorination reactions.

Selective separation of fluorinated compounds from complex organic mixtures by pyrolysis-comprehensive two-dimensional gas chromatography coupled to high-resolution time-of-flight mass spectrometry.

PubMed

Nakajima, Yoji; Arinami, Yuko; Yamamoto, Kiyoshi

2014-12-29

The usefulness of comprehensive two-dimensional gas chromatography (GC×GC) was demonstrated for the selective separation of fluorinated compounds from organic mixtures, such as kerosene/perfluorokerosene mixtures, pyrolysis products derived from polyethylene/ethylene-tetrafluoroethylene alternating copolymer mixture and poly[2-(perfluorohexyl)ethyl acrylate]. Perfluorocarbons were completely separated from hydrocarbons in the two-dimensional chromatogram. Fluorohydrocarbons in the pyrolysis products of polyethylene/ethylene-tetrafluoroethylene alternating copolymer mixture were selectively isolated from their hydrocarbon counterparts and regularly arranged according to their chain length and fluorine content in the two-dimensional chromatogram. A reliable structural analysis of the fluorohydrocarbons was achieved by combining effective GC×GC positional information with accurate mass spectral data obtained by high-resolution time-of-flight mass spectrometry (HRTOF-MS). 2-(Perfluorohexyl)ethyl acrylate monomer, dimer, and trimer as well as 2-(perfluorohexyl)ethyl alcohol in poly[2-(perfluorohexyl)ethyl acrylate] pyrolysis products were detected in the bottommost part of the two-dimensional chromatogram with separation from hydrocarbons possessing terminal structure information about the polymer, such as α-methylstyrene. Pyrolysis-GC×GC/HRTOF-MS appeared particularly suitable for the characterization of fluorinated polymer microstructures, such as monomer sequences and terminal groups. Copyright © 2014 Elsevier B.V. All rights reserved.

Detection of carbon-fluorine bonds in organofluorine compounds by Raman spectroscopy using a copper-vapor laser

NASA Astrophysics Data System (ADS)

Sharts, Clay M.; Gorelik, Vladimir S.; Agoltsov, A. M.; Zlobina, Ludmila I.; Sharts, Olga N.

1999-02-01

The Raman spectra of fluoro-organic compounds show specific emission bands for carbon-fluorine bonds in the range 500- 800 wave numbers (cm-1)). With very limited exceptions, biological materials do not contain carbon- fluorine bonds. Fluoro-organic compounds introduced into biological samples can be detected by a Raman emission signal. Normal mode C-F bond bands are observed: (1) at 710- 785 cm -1 for trifluoromethyl groups; (2) at 530-610 cm -1 for aromatic organofluorine bonds; (3) a range centered at 690 cm -1 for difluoromethylene groups. Specific examples of normal mode C-F bond emissions for organofluorine compounds containing trifluoromethyl groups are: 1-bromoperfluorooctane, 726 cm -1; perfluorodecanoic acid, 730 cm -1; triperfluoropropylamine, 750 cm -1; 1,3,5-tris- (trifluoromethyl)-benzene, 730 cm -1; Fluoxetine (Prozac) commercial powdered pill at 782 cm -1. Compounds containing aromatic C-F bonds are: hexafluorobenzene, 569 cm MIN1; pentafluoropyridine, 589 cm -1. Difluoromethylene groups: perfluorodecalin, 692 cm-1; perfluorocyclohexane, 691 cm -1. Raman spectra were observed with a standard single monochromator. The 510.8 nm light source was a copper-vapor laser operated at 3-10 watts with 10-12 nanosecond pulses at 10 kHz repetition rate. Detection was made with a time-gated photomultiplier tube. Resonance Raman spectra were also observed at 255.4 nm, using a frequency doubling crystal. Observed spectra were free of fluorescence with very sharp strong C-F lines.

Phenyl boron-based compounds as anion receptors for non-aqueous battery electrolytes

DOEpatents

Lee, Hung Sui; Yang, Xiao-Qing; McBreen, James; Sun, Xuehui

2002-01-01

Novel fluorinated boronate-based compounds which act as anion receptors in non-aqueous battery electrolytes are provided. When added to non-aqueous battery electrolytes, the fluorinated boronate-based compounds of the invention enhance ionic conductivity and cation transference number of non-aqueous electrolytes. The fluorinated boronate-based anion receptors include different fluorinated alkyl and aryl groups.

Synthesis, crystal structure and antimicrobial potential of some fluorinated chalcone-1,2,3-triazole conjugates.

PubMed

Yadav, Pinki; Lal, Kashmiri; Kumar, Lokesh; Kumar, Ashwani; Kumar, Anil; Paul, Avijit K; Kumar, Rajnish

2018-06-02

A simple and green synthesis of some fluorinated chalcone-triazole hybrids from propargylated chalcones and organic azides catalyzed by cellulose supported copper nanoparticles click reaction is reported. All the synthesized compounds were well characterized by various analytical and spectroscopic methods. The X-rays crystallographic study of compounds 6k revealed the self assembling properties. The antimicrobial screening results of all the synthesized compounds revealed that most of the triazole hybrids exhibited significant efficacy against tested bacterial and fungal strains. The activity results showed the synergistic effect of biological activity when two pharmacophoric units, i.e. chalcone and 1,2,3-triazole are conjugated. Further, docking simulation of the most active compounds 6p into Escherichia coli topoisomerase II DNA Gyrase B was also carried out. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Fluorination process using catalyst

DOEpatents

Hochel, Robert C.; Saturday, Kathy A.

1985-01-01

A process for converting an actinide compound selected from the group consisting of uranium oxides, plutonium oxides, uranium tetrafluorides, plutonium tetrafluorides and mixtures of said oxides and tetrafluorides, to the corresponding volatile actinide hexafluoride by fluorination with a stoichiometric excess of fluorine gas. The improvement involves conducting the fluorination of the plutonium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF.sub.3, AgF.sub.2 and NiF.sub.2, whereby the fluorination is significantly enhanced. The improvement also involves conducting the fluorination of one of the uranium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF.sub.3 and AgF.sub.2, whereby the fluorination is significantly enhanced.

Fluorination process using catalysts

DOEpatents

Hochel, R.C.; Saturday, K.A.

1983-08-25

A process is given for converting an actinide compound selected from the group consisting of uranium oxides, plutonium oxides, uranium tetrafluorides, plutonium tetrafluorides and mixtures of said oxides and tetrafluorides, to the corresponding volatile actinide hexafluoride by fluorination with a stoichiometric excess of fluorine gas. The improvement involves conducting the fluorination of the plutonium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF/sub 3/, AgF/sub 2/ and NiF/sub 2/, whereby the fluorination is significantly enhanced. The improvement also involves conducting the fluorination of one of the uranium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF/sub 3/ and AgF/sub 2/, whereby the fluorination is significantly enhanced.

Organofluorine chemistry: synthesis and conformation of vicinal fluoromethylene motifs.

PubMed

O'Hagan, David

2012-04-20

The C-F bond is the most polar bond in organic chemistry, and thus the bond has a relatively large dipole moment with a significant -ve charge density on the fluorine atom and correspondingly a +ve charge density on carbon. The electrostatic nature of the bond renders it the strongest one in organic chemistry. However, the fluorine atom itself is nonpolarizable, and thus, despite the charge localization on fluorine, it is a poor hydrogen-bonding acceptor. These properties of the C-F bond make it attractive in the design of nonviscous but polar organic compounds, with a polarity limited to influencing the intramolecular nature of the molecule and less so intermolecular interactions with the immediate environment. In this Perspective, the synthesis of aliphatic chains carrying multivicinal fluoromethylene motifs is described. It emerges that the dipoles of adjacent C-F bonds orientate relative to each other, and thus, individual diastereoisomers display different backbone carbon chain conformations. These conformational preferences recognize the influence of the well-known gauche effect associated with 1,2-difluoroethane but extend to considering 1,3-fluorine-fluorine dipolar repulsions. The synthesis of carbon chains carrying two, three, four, five, and six vicinal fluoromethylene motifs is described, with an emphasis on our own research contributions. These motifs obey almost predictable conformational behavior, and they emerge as candidates for inclusion in the design of performance organic molecules. © 2012 American Chemical Society

21 CFR 170.45 - Fluorine-containing compounds.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Fluorine-containing compounds. 170.45 Section 170.45 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD ADDITIVES Specific Administrative Rulings and Decisions § 170.45 Fluorine-containing compounds...

Design and fabrication of chemically robust three-dimensional microfluidic valves.

PubMed

Maltezos, George; Garcia, Erika; Hanrahan, Grady; Gomez, Frank A; Vyawahare, Saurabh; Vyawhare, Saurabh; van Dam, R Michael; Chen, Yan; Scherer, Axel

2007-09-01

A current problem in microfluidics is that poly(dimethylsiloxane) (PDMS), used to fabricate many microfluidic devices, is not compatible with most organic solvents. Fluorinated compounds are more chemically robust than PDMS but, historically, it has been nearly impossible to construct valves out of them by multilayer soft lithography (MSL) due to the difficulty of bonding layers made of "non-stick" fluoropolymers necessary to create traditional microfluidic valves. With our new three-dimensional (3D) valve design we can fabricate microfluidic devices from fluorinated compounds in a single monolithic layer that is resistant to most organic solvents with minimal swelling. This paper describes the design and development of 3D microfluidic valves by molding of a perfluoropolyether, termed Sifel, onto printed wax molds. The fabrication of Sifel-based microfluidic devices using this technique has great potential in chemical synthesis and analysis.

New approach to the fast screening of plant oil samples for F-, Cl-, Br- and S-organic compounds on the trace level.

PubMed

Chivarzin, M E; Revelsky, I A; Nikoshina, A V; Buldyzkova, A N; Chepeliansky, D A; Revelsky, A I; Buriak, A K

2016-04-01

The fast method of the simultaneous determination of F(-), Cl(-), Br(-) and SO4(2-) anions in the deionized water on the trace level by ion chromatography using thorough cleaning of respective water containers, 10 μM NaHCO3 water solution as eluent, short Metrohm (50 × 4 mm) separation column and a large water volume injection is proposed. Calculated detection limits are 10(-9)-10(-8)% depending on the element. The method for the fast screening of plant oil samples for the total fluorine-, chlorine-, bromine- and sulfur-organic compounds content (calculated for the respective elements) on the trace level is developed. It is based on the high temperature combustion of oil sample in oxygen flow, absorption of the conversion products in deionized water and whole absorbate volume analysis for F(-), Cl(-), Br(-) and SO4(2-) anions, corresponding to the respective elements, using the developed method of these anions analysis by ion chromatography. The samples of soya, olive, sunflower and cotton seed oil were analyzed. The method detection limits (for 1mg sample) were 2 × 10(-6)%, 2 × 10(-6)%, 5 × 10(-6)% and 5 × 10(-6)% for fluorine, chlorine, bromine and sulfur, respectively. The relative standard deviation was ≤ 15%. The method gives the compressed information about the total content of all target and nontarget fluorine-, chlorine-, bromine- and sulfur-organic compounds in plant oils. Copyright © 2015. Published by Elsevier B.V.

Joy and flustration with organofluorine compounds - a fluorous autobiography.

PubMed

Seebach, Dieter

2014-01-01

An overview is given about our work on fluoro-organic compounds, published or described in PhD theses between 1977 and 2013. After a discussion of structural F-effects and F-tagging applications the material is ordered by the various areas of our research, in which we have used and/or prepared F-derivatives: Li- and Ti-organic compounds and reagents, polylithiated hydroxy-esters and nitroalkanes, the enantiopure trifluoro-lactic, -Roche, and -3-hydroxy-butanoic acids as toolbox for the preparation of numerous F₃C-substituted compounds, including natural products and dendrimers, and fluoro-α-, -β-, and -δ-amino acids, as well as peptides with back-bond-bound fluorine. The strong influence on β-peptide folding by fluoro-substituents in the α-position of β-amino-acid residues is discussed in terms of the α-fluoro-amide conformational effect. Finally, some cases of totally unexpected effects on reactivity and structure exerted by fluoro-substitution are presented and taken as examples for our use of the terms flustrate and flustration in connection with organo-fluorine chemistry.

Comparison of perfluorooctanoic acid mobility in soil with and without alfalfa

USDA-ARS?s Scientific Manuscript database

Perfluorooctanoic acid (PFOA) is a fully fluorinated organic compound (C8HF15O2) that is widely used in consumer products as a surfactant because of its chemical resistance to stains, grease, and water. Perfluorooctanoic acid is a persistent organic pollutant because it is globally distributed, stab...

Organohalogen Pollutants and Human Health

EPA Science Inventory

During the past century, a vast number of organic chemicals have been manufactured and used in industrial, agricultural, public health, consumer products and other applications. Widespread use of organohalogens, including chlorinated, brominated and fluorinated compounds, lead to...

Diastereoselective Diels-Alder reactions of alpha-fluorinated alpha,beta-unsaturated carbonyl compounds: chemical consequences of fluorine substitution. 2.

PubMed

Essers, Michael; Mück-Lichtenfeld, Christian; Haufe, Günter

2002-07-12

Two alpha-fluoro alpha,beta-unsaturated carbonyl compounds, i.e., benzyl 2-fluoroacrylate (3) and 2-fluorooct-1-en-3-one (4), as well as the corresponding nonfluorinated parent compounds, were synthesized and subjected to Diels-Alder reactions with cyclopentadiene. The cycloadditions were conducted thermally, microwave-assisted, and Lewis acid-mediated (TiCl(4)). The fluorinated dienophiles exhibited a lower reactivity and exo diastereoselectivity, while the corresponding nonfluorinated parent compounds reacted endo selectively. DFT calculations suggest that kinetic effects of fluorine determine the stereoselectivity rather than higher thermodynamic stability of the exo products.

SEPARATION PROCESS FOR TRANSURANIC ELEMENT AND COMPOUNDS THEREOF

DOEpatents

Magnusson, L.B.

1958-04-01

A process is described for the separation of neptunium, from aqueous solutions of neptunium, plutonium, uraniunn, and fission prcducts. This separation from an acidic aqueous solution of a tetravalent neptuniunn can be made by contacting the solution with a certain type of chelating,; agent, preferably dissolved in an organic solvent, to form a neptunium chelate compound. When the organic solvent is present, the neptunium chelate compound is extracted; otherwise, it precipitates from the aqueous solution and is separated by any suitable means. The chelating agent is a fluorinated BETA -diketone. such as trifluoroacetyl acetone.

Combined ab initio/empirical approach for optimization of Lennard-Jones parameters for polar-neutral compounds.

PubMed

Chen, I Jen; Yin, Daxu; MacKerell, Alexander D

2002-01-30

The study of small functionalized organic molecules in aqueous solution is a useful step toward gaining a basic understanding of the behavior of biomolecular systems in their native aqueous environment. Interest in studying amines and fluorine-substituted compounds has risen from their intrinsic physicochemical properties and their prevalence in biological and pharmaceutical compounds. In the present study, a previously developed approach which optimizes Lennard-Jones (LJ) parameters via the use of rare gas atoms combined with the reproduction of experimental condensed phase properties was extended to polar-neutral compounds. Compounds studied included four amines (ammonia, methylamine, dimethylamine, and trimethylamine) and three fluoroethanes (1-fluoroethane, 1,1-difluoroethane, and 1,1,1-trifluoroethane). The resulting force field yielded heats of vaporization and molecular volumes in excellent agreement with the experiment, with average differences less than 1%. The current amine CHARMM parameters successfully reproduced experimental aqueous solvation data where methylamine is more hydrophilic than ammonia, with hydrophobicity increasing with additional methylation on the nitrogen. For both the amines and fluoroethanes the parabolic relationship of the extent of methylation or fluorination, respectively, to the heats of vaporization were reproduced by the new parameters. The present results are also discussed with respect to the impact of parameterization approach to molecular details obtained from computer simulations and to the unique biological properties of fluorine in pharmaceutical compounds.

Biological effect of fluoride on plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collet, G.F.

1969-10-01

The action of several fluorine compounds was studied by means of hydroponics. Seedlings of several species were used. In leaves of Prunus armeniaca, a good correlation between the extent of necrosis and the leaf's total fluorine content was noted. Boron plays a spectacular role as it enhances the expected fluorine accumulation. Similar results were obtained with other plant material, an observation which suggests that this phenomenon is universal in plant life. Fluorine accumulation and leaf damage due to fluorine depend upon the chemical nature of the fluorine compound. 11 references, 3 figures, 2 tables.

The Electrochemical Fluorination of Organosilicon Compounds

NASA Technical Reports Server (NTRS)

Seaver, Robert E.

1961-01-01

The electrochemical fluorination of tetramethylsilane, hexamethyl-disiloxane, diethyldichlorosilane, amyltrichlorosilane, and phenyltri-chlorosilane was conducted in an Inconel cell equipped with nickel electrodes. A potential of approximately 5.0 volts and a current of approximately 1.0 ampere were used for the electrolysis reaction. In all cases the fluorinations resulted in considerable scission of the carbon-silicon bonds yielding hydrogen and the various fluorinated decomposition products; no fluoroorganosilicon compounds were identified. The main decomposition products were silicon tetrafluoride, the corresponding fluorinated carbon compounds, and the various organofluorosilanes. It is suggested that this is due to the nucleophilic attack of the fluoride ion (or complex fluoride ion) on the carbon-silicon bond.

Ms No. 02858: Organohalogen Pollutants and Human Health

EPA Science Inventory

During the past century, a vast number of organic chemicals have been manufactured and used in industrial, agricultural, public health, consumer products and other applications. The organohalogens, including chlorinated, brominated and fluorinated compounds, are ubiquitous in th...

Perfluoroalkyl substances and extractable organic fluorine in surface sediments and cores from Lake Ontario.

PubMed

Yeung, Leo W Y; De Silva, Amila O; Loi, Eva I H; Marvin, Chris H; Taniyasu, Sachi; Yamashita, Nobuyoshi; Mabury, Scott A; Muir, Derek C G; Lam, Paul K S

2013-09-01

Fourteen perfluoroalkyl substances (PFASs) including short-chain perfluorocarboxylates (PFCAs, C4-C6) and perfluoroalkane sulfonates (PFSAs, C4 and C6) were measured in surface sediment samples from 26 stations collected in 2008 and sediment core samples from three stations (Niagara, Mississauga, and Rochester basins) collected in 2006 in Lake Ontario. Perfluorooctanesulfonate (PFOS), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorodecanoate (PFDA), and perfluoroundecanoate (PFUnDA) were detected in all 26 surface sediment samples, whereas perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonamide (FOSA), perfluorododecanoate (PFDoDA) and perfluorobutanoate (PFBA) were detected in over 70% of the surface sediment samples. PFOS was detected in all of the sediment core samples (range: 0.492-30.1ngg(-1) d.w.) over the period 1952-2005. The C8 to C11 PFCAs, FOSA, and PFBA increased in early 1970s. An overall increasing trend in sediment PFAS concentrations/fluxes from older to more recently deposited sediments was evident in the three sediment cores. The known PFCAs and PFSAs accounted for 2-44% of the anionic fraction of the extractable organic fluorine in surface sediment, suggesting that a large proportion of fluorine in this fraction remained unknown. Sediment core samples collected from Niagara basin showed an increase in unidentified organic fluorine in recent years (1995-2006). These results suggest that the use and manufacture of fluorinated organic compounds other than known PFCAs and PFSAs has diversified and increased. © 2013.

Determination of Fluorine in Fluoro-Organic Compounds in Low Concentrations in Air

DTIC Science & Technology

1944-06-27

Analysis of 2-Fluoroethanol in Air ..... SUMMARY BIBLIOGRAPHY 15 APPENDIX , 16 FIGURE 1 Apparatus PLATE 1 CDS Scrubber SECRET ) SECRET...liter, and 68$ at 1 - 2 mg. per liter. By using two scrubbers in series, 90$ of di-isopropyl fluorophosphate was recovered at a concentration of 1 to 2...chromic acid and detection of HP by etching of the glass container ; (5) scrub- bing the gas with ammonia and decomposing the fluoro-organic compound4

The Strength of Hydrogen Bonds between Fluoro-Organics and Alcohols, a Theoretical Study.

PubMed

Rosenberg, Robert E

2018-05-10

Fluorinated organic compounds are ubiquitous in the pharmaceutical and agricultural industries. To better discern the mode of action of these compounds, it is critical to understand the strengths of hydrogen bonds involving fluorine. There are only a few published examples of the strengths of these bonds. This study provides a high level ab initio study of inter- and intramolecular hydrogen bonds between RF and R'OH, where R and R' are aryl, vinyl, alkyl, and cycloalkyl. Intermolecular binding energies average near 5 kcal/mol, while intramolecular binding energies average about 3 kcal/mol. Inclusion of zero-point energies and applying a counterpoise correction lessen the difference. In both series, modest increases in binding energies are seen with increased acidity of R'OH and increased electron donation of R in RF. In the intramolecular compounds, binding energy increases with the rigidity of the F-(C) n -OH ring. Inclusion of free energy corrections at 298 K results in exoergic binding energies for the intramolecular compounds and endoergic binding energies for the intermolecular compounds. Parameters such as bond lengths, vibrational frequencies, and atomic populations are consistent with formation of a hydrogen bond and with slightly stronger binding in the intermolecular cases over the intramolecular cases. However, these parameters correlated poorly with binding energies.

The rare fluorinated natural products and biotechnological prospects for fluorine enzymology.

PubMed

Chan, K K Jason; O'Hagan, David

2012-01-01

Nature has hardly evolved a biochemistry of fluorine although there is a low-level occurrence of fluoroacetate found in selected tropical and subtropical plants. This compound, which is generally produced in low concentrations, has been identified in the plants due to its high toxicity, although to date the biosynthesis of fluoroacetate in plants remains unknown. After that, fluorinated entities in nature are extremely rare, and despite increasingly sophisticated screening and analytical methods applied to natural product extraction, it has been 25 years since the last bona fide fluorinated natural product was identified from an organism. This was the reported isolation of the antibiotic 4-fluorothreonine and the toxin fluoroacetate in 1986 from Streptomyces cattleya. This bacterium has proven amenable to biochemical investigation, the fluorination enzyme (fluorinase) has been isolated and characterized, and the biosynthetic pathway to these bacterial metabolites has been elucidated. Also the fluorinase gene has been cloned into a host bacterium (Salinispora tropica), and this has enabled the de novo production of a bioactive fluorinated metabolite from fluoride ion, by genetic engineering. Biotechnological manipulation of the fluorinase offers the prospects for the assembly of novel fluorinated metabolites by fermentation technology. This is particularly attractive, given the backdrop that about 15-20% of pharmaceuticals licensed each year (new chemical entities) contain a fluorine atom. Copyright © 2012 Elsevier Inc. All rights reserved.

Chemical of the Month: Nitric Acid.

ERIC Educational Resources Information Center

Pannu, Sardul S.

1984-01-01

Presents background information on nitric acid including old names, history, occurrence, methods of preparation, uses, production, and price. Includes such chemical properties as decomposition; acidity, oxidation of metals and nonmetals; reactions with organic and inorganic compounds; gaseous fluorine; and nitrating properties. Also discusses bond…

PROCESS FOR PURIFYING CRUDE PERFLUOROCARBONS

DOEpatents

Holeton, R.E.

1959-03-24

A method is described for refining organic perfluoro compounds. In the manufacture of perfluorinated compounds by the fluorination of hydrocarbons, the product frequently is contaminated ny incompletely fluorimated hydrogen containing impurities. These impurities can be removed by contacting the products in a fluid conditions with an active adsorbents such as silica gel or alumina gel. The patent claims are restricted to this refining of crude perfluorinated lubricating oil.

Lipophilic Super-Absorbent Swelling Gels as Cleaners for Use on Weapons Systems and Platforms

DTIC Science & Technology

2011-08-18

polymer gel systems. Further research will address the post-cleaning gel removal method, the use of non- fluorinated compounds in gel synthesis, and...be proposed to address other issues including the method for removing the gels after swelling, the use of non- fluorinated compounds in gel...strength. Elimination of fluorinated compounds in the gel synthesis was the focus of this and subsequent phases of this research. TECHNICAL APPROACH

Low-Absorption Liquid Crystals for Infrared Beam Steering

DTIC Science & Technology

2013-10-22

Low absorption, MWIR, chlorinated liquid crystals, fluorination, FTIR, eutectic mixture, deuteration, nematic phase, birefringence, overtone...absorption compounds for LWIR and SWIR are also investigated. Key words: Low absorption, MWIR, chlorinated liquid crystals, fluorination, FTIR, eutectic ...the melting point significantly. We did careful investigation and formed a eutectic mixture consisting of five fluorinated compounds without any

[Fluorine as a factor in premature aging].

PubMed

Machoy-Mokrzyńska, Anna

2004-01-01

The use of fluorine compounds in various areas of medicine, particularly in dentistry, as well as in agriculture and industry became very popular in the second half of the 20th century. Fluorine owed this widespread acceptance to observations that its compounds stimulate ossification processes and reduce the prevalence of caries. Unfortunately, growing expectations overshadowed the truth regarding interactions of fluoride on the molecular level. The fact was often ignored that fluoride is toxic, even though laboratory data stood for a careful approach to the benefits of usage. Excessive exposure to fluoride may lead to acute poisoning, hyperemia, cerebral edema, and degeneration of the liver and kidneys. Acute intoxication through the airways produces coughing, choking, and chills, followed by fever and pulmonary edema. Concentrated solutions of fluorine compounds produce difficult to heal necrotic lesions. In spite of these dramatic symptoms, acute intoxications are relatively rare; the more common finding is chronic intoxication attributable to the universal presence of fluorine compounds in the environment. The first noticeable signs of excessive exposure to fluoride in contaminated water, air, and food products include discolorations of the enamel. Dental fluorosis during tooth growth and loss of dentition in adulthood are two consequences of chronic intoxication with fluorine compounds. Abnormalities in mineralization processes affect by and large the osteoarticular system and are associated with changes in the density and structure of the bone presenting as irregular mineralization of the osteoid. Fluorine compounds also act on the organic part of supporting tissues, including collagen and other proteins, and on cells of the connective tissue. These interactions reduce the content of collagen proteins, modify the structure and regularity of collagen fibers, and induce mineralization of collagen. Interactions with cells produce transient activation of osteoblasts, stimulate fibroblasts to produce collagenase, and trigger toxic reactions in osteocytes and chondrocytes of trabecular bone. Growing deformations of the skeleton reduce mobility and result in permanent crippling of the patient. Fluoride increases the mass of non-collagen proteins such as proteoglycans and glucosaminoglycans, accelerating skin aging even though protein biosynthesis is generally suppressed. The final outcome includes progressive vascular lesions and disorders of energy metabolism in muscles. In conclusions, the use of fluoride, particularly by dentists and pediatricians, must be controlled and adapted to individual needs. It is worth remembering that fluoride: is the cause of disability due to bone deformations and abnormalities in the musculoskeletal system; reduces the incidence of caries but do not protect against tooth loss; exerts an adverse effect of metabolic processes in the skin; accelerates calcification of vessels and thus reduces their elasticity; inhibits bioenergetic reactions, in particular oxidative phosphorylation, reducing physical activity of muscles. These findings suggest that fluorine may be yet another factor in accelerated aging and revive the dispute started more than two and half thousand years ago whether aging is a physiologic or pathologic process. The understanding of factors modifying the process of aging is the basis for preventive measures aimed at extending life and maintaining full psychosocial activity.

Fluorinated Compounds in US Fast Food Packaging | Science ...

EPA Pesticide Factsheets

Per- and polyfluoroalkyl substances (PFASs) are highly persistent synthetic chemicals, some of which have been associated with cancer, developmental toxicity, immunotoxicity, and other health effects. PFASs in grease-resistant food packaging can leach into food and increase dietary exposure. We collected ∼400 samples of food contact papers, paperboard containers, and beverage containers from fast food restaurants throughout the United States and measured total fluorine using particle-induced γ-ray emission (PIGE) spectroscopy. PIGE can rapidly and inexpensively measure total fluorine in solid-phase samples. We found that 46% of food contact papers and 20% of paperboard samples contained detectable fluorine (>16 nmol/cm2). Liquid chromatography/high-resolution mass spectrometry analysis of a subset of 20 samples found perfluorocarboxylates, perfluorosulfonates, and other known PFASs and/or unidentified polyfluorinated compounds (based on nontargeted analysis). The total peak area for PFASs was higher in 70% of samples (10 of 14) with a total fluorine level of >200 nmol/cm2 compared to six samples with a total fluorine level of <16 nmol/cm2. Samples with high total fluorine levels but low levels of measured PFASs may contain volatile PFASs, PFAS polymers, newer replacement PFASs, or other fluorinated compounds. The prevalence of fluorinated chemicals in fast food packaging demonstrates their potentially significant contribution to dietary PFAS exposure and envi

Synthesis, crystal structure and photo physical properties of isomeric fluorinated s-shaped polyaromatic dibenzo[c,l]chrysene derivatives

NASA Astrophysics Data System (ADS)

Moriguchi, Tetsuji; Tabuchi, Daichi; Yakeya, Daisuke; Tsuge, Akihiko; Jalli, Venkataprasad; Yoza, Kenji

2018-01-01

Two s-shaped fluorinated isomeric polyaromatic dibenzo[c,l]chrysene derivatives have been synthesized by a two step process using the Wittig, Heck and iodine promoted cyclization reactions. These cyclized compounds were characterized by 1H NMR and EI-MS. Further, absolute configurations of isomeric 4a and 4b were determined by X-ray diffraction analysis. Compound 4a crystallized under monoclinic system with space group P21/c and compound 4b crystallized under monoclinic system with space group Cc. They have good solubility in common organic solvents such as dichloromethane, chloroform and THF. Photophysical properties of 4a and 4b were evaluated by using UV-Visible and Fluorescence spectrophotometer. Compounds 4a and 4b showed strong absorption maximum wavelength at 317 nm. The emission spectra of 4a and 4b displayed sharp peaks in the visible region from 417 to 441 nm. The shape of the UV-Visible and Fluorescence spectra of 4a and 4b looks almost identical. But compound 4a exhibited better fluorescence intensity than compound 4b. This difference may be due to the difference in the configuration of compounds 4a and 4b.

Handling and Use of Fluorine and Fluorine - Oxygen Mixtures in Rocket Systems,

DTIC Science & Technology

1967-01-01

with nitroso rubber, which could normally be expected to burn when exposed to the flow of liquid fluorine. The materials tested included (1) Nitroso...the system free of contamination. Most common metals of construction are compatible for use in a fluorine environment. Metals can burn with fluorine...conditions of contact), fluorinated compounds in their highest state of oxidation, and a few fluorinated polymers. Even these polymers may burn in fluorine

Synthesis and Structural Characterization of New High-Valent Inorganic Fluorine Compounds and their Oxidizing Properties. Volume 3

DTIC Science & Technology

1992-02-01

COMPOUNDS AND T•EIR OXIDIZING PROPERTIES: VOLUME 3. Prof. G.J. Schrobilgen DTI.DTIC_* Mc Mastf-• University f ELECTE Department of Chemistry JUN 16...STRUCTURAL CHARACTERIZATION OF NEW HIGH- C - F49620-87-C-0049 VALENT INORGANIC FLUORINE COMPOUNDS AND THEIR OXIDIZING PR- 5730 PROPERTIES TA- 007C S6...fluorine, oxidizers of Neon, Krypton. Argon, and Xenon have been synthesized and characterized. KrF+ and ),eF+ caticmns have been made with neutral

Solid-phase organic synthesis of difluoroalkyl entities using a novel fluorinating cleavage strategy: part 1. Linker development: scope and limitations.

PubMed

Wiehn, Matthias S; Lindell, Stephen D; Bräse, Stefan

2009-01-01

An efficient method to synthesize gem-difluorinated compounds on solid supports is described. The strategy is based on the design of a novel sulfur linker system that enables, to the best of our knowledge for the first time, the release of target structures from the resin under simultaneous fluorination. Starting from an immobilized dithiol, coupling with an excess of aldehyde or ketone furnished dithianes. These can be further functionalized prior to release from the resin using our newly developed fluorinating cleavage conditions. Amide forming reactions, palladium-catalyzed reactions (Heck, Suzuki, and Sonogashira couplings), reductions, alkylations, and olefinations were successfully explored on the linker. The difluorinated target substances were obtained in modest to excellent yields and in high purities.

The use of fluoroepoxy compounds as adhesives to bond fluoroplastics without any surface treatment

NASA Technical Reports Server (NTRS)

Lee, Sheng Yen

1988-01-01

The use of fluoroepoxy compounds as adhesives to bond fluoroplastics was investigated. Fluoroepoxy compounds with a F-content higher than 46 percent were able to bond a highly fluorinated plastic such as Teflon PTFE (76 percent F) to give a respectable bond strength without any surface treatment. The advantage of the fluoroepoxy adhesive vanished when applied to a less fluorinated plastic such as Tefzel which contains 55 percent fluorine. Among the curing agents explored, octafluorooctamethylenediamine showed its potential as a cocuring agent for improving both the viscosity of the compound and the flexibility of the cured product.

Electrokinetic remediation of fluorine-contaminated soil and its impact on soil fertility.

PubMed

Zhou, Ming; Wang, Hui; Zhu, Shufa; Liu, Yana; Xu, Jingming

2015-11-01

Compared to soil pollution by heavy metals and organic pollutants, soil pollution by fluorides is usually ignored in China. Actually, fluorine-contaminated soil has an unfavorable influence on human, animals, plants, and surrounding environment. This study reports on electrokinetic remediation of fluorine-contaminated soil and the effects of this remediation technology on soil fertility. Experimental results showed that electrokinetic remediation using NaOH as the anolyte was a considerable choice to eliminate fluorine in contaminated soils. Under the experimental conditions, the removal efficiency of fluorine by the electrokinetic remediation method was 70.35%. However, the electrokinetic remediation had a significant impact on the distribution and concentrations of soil native compounds. After the electrokinetic experiment, in the treated soil, the average value of available nitrogen was raised from 69.53 to 74.23 mg/kg, the average value of available phosphorus and potassium were reduced from 20.05 to 10.39 mg/kg and from 61.31 to 51.58 mg/kg, respectively. Meanwhile, the contents of soil available nitrogen and phosphorus in the anode regions were higher than those in the cathode regions, but the distribution of soil available potassium was just the opposite. In soil organic matter, there was no significant change. These experiment results suggested that some steps should be taken to offset the impacts, after electrokinetic treatment.

Mutasynthesis of fluorinated pactamycin analogues and their antimalarial activity.

PubMed

Almabruk, Khaled H; Lu, Wanli; Li, Yuexin; Abugreen, Mostafa; Kelly, Jane X; Mahmud, Taifo

2013-04-05

A mutasynthetic strategy has been used to generate fluorinated TM-025 and TM-026, two biosynthetically engineered pactamycin analogues produced by Streptomyces pactum ATCC 27456. The fluorinated compounds maintain excellent activity and selectivity toward chloroquine-sensitive and multidrug-resistant strains of malarial parasites as the parent compounds. The results also provide insights into the biosynthesis of 3-aminobenzoic acid in S. pactum.

Self-Cleaning Coatings

DTIC Science & Technology

2014-06-01

Canada), telle que representee par le ministre de la Defense nationale, 2014 i Abstract Under certain conditions, military coatings...μm Particle C: a compound of fluorinated polymer and polypropylene , mean particle size 9 μm Due to the fact that all three types of particles have...functional particles, which are either pure fluorinated polymer or compound of fluorinated polymer and polypropylene , possessing certain degrees of

Fluorine-18 labeled tracers for PET studies in the neurosciences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Yu-Shin; Fowler, J.S.

This chapter focuses on fluorine-18, the positron emitter with the longest half-life, the lowest positron energy and probably, the most challenging chemistry. The incorporation of F-18 into organic compounds presents many challenges, including: the need to synthesize and purify the compound within a 2--3 hour time frame; the limited number of labeled precursor molecules; the need to work on a microscale; and the need to produce radiotracers which are chemically and radiochemically pure, sterile and pyrogen-free, and suitable for intravenous injection. The PET method and F-18 labeling of organic molecules are described followed by highlights of the applications of F-18more » labeled compounds in the neurosciences and neuropharmacology. It is important to emphasize the essential and pivotal role that organic synthesis has played in the progression of the PET field over the past twenty years from one in which only a handful of institutions possessed the instrumentation and staff to carry out research to the present-day situation where there are more than 200 PET centers worldwide. During this period PET has become an important scientific tool in the neurosciences, cardiology and oncology. It is important to point out that PET is by no means a mature field. The fact that a hundreds of different F-18 labeled compounds have been developed but only a few possess the necessary selectivity and sensitivity in vivo to track a specific biochemical process illustrates this and underscores a major difficulty in radiotracer development, namely the selection of priority structures for synthesis and the complexities of the interactions between chemical compounds and living systems. New developments in rapid organic synthesis are needed in order to investigate new molecular targets and to improve the quantitative nature of PET experiments.« less

Gas Separation Using Organic-Vapor-Resistent Membranes In Conjunctin With Organic-Vapor-Selective Membranes

DOEpatents

Baker, Richard W.; Pinnau, Ingo; He, Zhenjie; Da Costa, Andre R.; Daniels, Ramin; Amo, Karl D.; Wijmans, Johannes G.

2003-06-03

A process for treating a gas mixture containing at least an organic compound gas or vapor and a second gas, such as natural gas, refinery off-gas or air. The process uses two sequential membrane separation steps, one using membrane selective for the organic compound over the second gas, the other selective for the second gas over the organic vapor. The second-gas-selective membranes use a selective layer made from a polymer having repeating units of a fluorinated polymer, and demonstrate good resistance to plasticization by the organic components in the gas mixture under treatment, and good recovery after exposure to liquid aromatic hydrocarbons. The membrane steps can be combined in either order.

.sup.18 F-4-Fluoroantipyrine

DOEpatents

Shiue, Chyng-Yann; Wolf, Alfred P.

1984-03-13

The novel radioactive compound .sup.18 F-4-fluoroantipyrine having high specific activity which can be used in nuclear medicine in diagnostic applications, prepared by the direct fluorination of antipyrine in acetic acid with radioactive fluorine at room temperature and purifying said radioactive compound by means of gel chromatography with ethyl acetate as eluent is disclosed. The non-radioactive 4-fluoroantipyrine can also be prepared by the direct fluorination of antipyrine in acetic acid with molecular fluorine at room temperature and purified by means of gel chromotography with ethyl acetate eluent.

SEPARATION PROCESS FOR ZIRCONIUM AND COMPOUNDS THEREOF

DOEpatents

Crandall, H.W.; Thomas, J.R.

1959-06-30

The separation of zirconium from columbium, rare earths, yttrium and the alkaline earth metals, such mixtures of elements occurring in zirconium ores or neutron irradiated uranium is described. According to the invention a suitable separation of zirconium from a one normal acidic aqueous solution containing salts, nitrates for example, of tetravalent zirconium, pentavalent columbium, yttrium, rare earths in the trivalent state and alkaline earths can be obtained by contacting the aqueous solution with a fluorinated beta diketonc alone or in an organic solvent solution, such as benzene, to form a zirconium chelate compound. When the organic solvent is present the zirconium chelate compound is directly extracted; otherwise it is separated by filtration. The zirconium may be recovered from contacting the organic solvent solution containing the chelated compound by back extraction with either an aqueous hydrofluoric acid or an oxalic acid solution.

Altering the Polymorphic Accessibility of Polycyclic Aromatic Hydrocarbons with Fluorination

DOE PAGES

Hiszpanski, Anna M.; Woll, Arthur R.; Kim, Bumjung; ...

2017-04-25

Here, substituting hydrogen with fluorine is an extensively employed strategy to improve the macroscopic properties of compounds for use in fields as diverse as pharmaceutics and optoelectronics. The role fluorine substitution plays on polymorphism—the ability of a compound to adopt more than one crystal structure—has not been previously studied. Yet, this understanding is important as different polymorphs of the same compound can result in drastically different bulk properties (e.g., solubility, absorptivity, and conductivity). Strategies to either promote or suppress the crystallization of particular polymorphs are thus desired. Here, we show that substituting hydrogen with fluorine affects the polymorphic behavior ofmore » contorted hexabenzocoronene (cHBC). A polycyclic aromatic hydrocarbon and molecular semiconductor, cHBC exhibits two polymorphs (i.e., P2 1/c crystal structure which we refer to as polymorph I and a triclinic crystal structure which we refer to as polymorph II) that are accessible through postdeposition processing of amorphous films. While the same two polymorphs remain accessible in fluorinated derivatives of cHBC, fluorination appears to favor the formation of polymorph I, with progressively smaller energy barrier for transformation from polymorph II to polymorph I with fluorination.« less

Altering the Polymorphic Accessibility of Polycyclic Aromatic Hydrocarbons with Fluorination

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hiszpanski, Anna M.; Woll, Arthur R.; Kim, Bumjung

Here, substituting hydrogen with fluorine is an extensively employed strategy to improve the macroscopic properties of compounds for use in fields as diverse as pharmaceutics and optoelectronics. The role fluorine substitution plays on polymorphism—the ability of a compound to adopt more than one crystal structure—has not been previously studied. Yet, this understanding is important as different polymorphs of the same compound can result in drastically different bulk properties (e.g., solubility, absorptivity, and conductivity). Strategies to either promote or suppress the crystallization of particular polymorphs are thus desired. Here, we show that substituting hydrogen with fluorine affects the polymorphic behavior ofmore » contorted hexabenzocoronene (cHBC). A polycyclic aromatic hydrocarbon and molecular semiconductor, cHBC exhibits two polymorphs (i.e., P2 1/c crystal structure which we refer to as polymorph I and a triclinic crystal structure which we refer to as polymorph II) that are accessible through postdeposition processing of amorphous films. While the same two polymorphs remain accessible in fluorinated derivatives of cHBC, fluorination appears to favor the formation of polymorph I, with progressively smaller energy barrier for transformation from polymorph II to polymorph I with fluorination.« less

Quantitative characterization of new supramolecular synthons involving fluorine atoms in the crystal structures of di- and tetrafluorinated benzamides.

PubMed

Mondal, Pradip Kumar; Yadav, Hare Ram; Choudhury, Angshuman Roy; Chopra, Deepak

2017-10-01

Strong hydrogen bonds play a significant role in crystal packing. In particular, the involvement of interactions involving fluorine in controlling the crystal packing requires appropriate attention, especially in the presence of other strong hydrogen bonds. In the present study, a detailed quantitative assessment has been performed of the nature, energetics and topological properties derived from the electron density in model compounds based on fluorinated benzamides (a total of 46 fluorine-substituted benzamides containing multiple fluorine atoms) in the solid state. The primary motivation in the design of such molecules is to enhance the acidity of the interacting H atoms in the presence of an increasing number of F atoms on the molecular scaffold, resulting in increased propensity towards the formation of intermolecular interactions involving organic fluorine. This exercise has resulted in the identification of new and frequently occurring supramolecular synthons involving F atoms in the packing of molecules in the solid state. The energetics associated with short and directional intermolecular Csp 2 -H...F-Csp 2 interactions with significantly high electrostatic contributions is noteworthy, and the topological analysis reveals the bonding character of these ubiquitous interactions in crystal packing in addition to the presence of Csp 2 -F...F-Csp 2 contacts.

Molecular beam epitaxy growth of SmFeAs(O,F) films with Tc = 55 K using the new fluorine source FeF3

NASA Astrophysics Data System (ADS)

Sakoda, Masahito; Ishii, Akihiro; Takinaka, Kenji; Naito, Michio

2017-07-01

REFeAs(O,F) (RE: rare-earth element) has the highest-Tc (˜58 K) among the iron-based superconductors, but a thin-film growth of REFeAs(O,F) is difficult. This is because it is not only a complex compound consisting of five elements but also requires doping of highly reactive fluorine to achieve superconductivity. We have reported in our previous article that fluorine can be supplied to a film by subliming solid-state fluorides such as FeF2 or SmF3. In this article, we report on the growth of SmFeAs(O,F) using FeF3 as an alternative fluorine source. FeF3 is solid at ambient temperatures and decomposes at temperatures as low as 100-200 °C, and releases fluorine-containing gas during the thermal decomposition. With this alternative fluorine source, we have grown SmFeAs(O,F) films with Tc as high as 55 K. This achievement demonstrates that FeF3 has potential as a fluorine source that can be employed ubiquitously for a thin-film growth of any fluorine containing compounds. One problem specific to FeF3 is that the compound is highly hydroscopic and contains a substantial amount of water even in its anhydrous form. In this article, we describe how to overcome this specific problem.

Identification and characterization of conservative organic tracers for use as hydrologic tracers for the Yucca Mountain Site characterization study; Progress report, April 1, 1993--June 30, 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dombrowski, T.; Stetzenbach, K.

1993-08-01

This report is in two parts one for the fluorinated benzoic acids and one for the fluorinated aliphatic acids. The assumptions made in the report regarding the amount of tracer that will be used, dilution of the tracer during the test and the length of exposure (if any) to individuals drinking the water were made by the authors. These assumptions must really come from the USGS hydrologists in charge of the c-well tracer testing program. Accurate estimates of dilution of the tracer during the test are also important because of solubility limitations of some of the tracers. Three of themore » difluorobenzoic acids have relatively low solubilities and may not be usable if the dilution estimates are large. The toxicologist that reviewed the document agreed with our conclusion that the fluorinated benzoic and toluic acids do not represent a health hazard if used under the conditions as outlined in the report. We are currently testing 15 of these compounds, and if even if three difluorobenzoic acids cannot be used because of solubility limitations we will still have 12 tracers. The toxicologist felt that the aliphatic fluorinated acids potentially present more of a health risk than the aromatic. This assessment was based on the fact of a known allergic response to halothane anesthetic. This risk, although minimal, is known and he felt that was enough reason to recommend against their use. The authors feel that the toxicologists interpretation of this risk was overly conservative, however, we will not go against his recommendation at this time for the following reasons. First, without the aliphatic compounds we still have 12 to 15 fluorinated aromatic acids which, should be enough for the c-well tests. Second, to get a permit to use aliphatic compounds would undoubtedly require a hearing which could be quite lengthy.« less

Graphite fluoride lubrication: The effect of fluorine content, atmosphere, and burnishing technique

NASA Technical Reports Server (NTRS)

Fusaro, R. L.

1975-01-01

Eight different graphite fluoride compounds with fluorine to carbon ratios varying from x = 0.25 to 1.1 were evaluated as burnished films in order to determine the effect of fluorine content on the solid lubricant properties of graphite fluoride. For comparison, similar experiments were conducted on graphite burnished films. It was found that even a small amount of fluorine in graphite fluoride (CF sub 0.25) sub n improved the lubricating properties of graphite. Such factors as burnishing atmosphere, burnishing technique, test atmosphere, and specimen temperature affected the results as much as varying the fluorine to carbon ratio of the compound. Best life was found for films that were machine-burnished in moist air and tested in moist air.

Can Csbnd H⋯Fsbnd C hydrogen bonds alter crystal packing features in the presence of Nsbnd H⋯Odbnd C hydrogen bond?

NASA Astrophysics Data System (ADS)

Yadav, Hare Ram; Choudhury, Angshuman Roy

2017-12-01

Intermolecular interactions involving organic fluorine have been the contemporary field of research in the area of organic solid state chemistry. While a group of researchers had refuted the importance of "organic fluorine" in guiding crystal structures, others have provided evidences for in favor of fluorine mediated interactions in the solid state. Many systematic studies have indicated that the "organic fluorine" is capable of offering weak hydrogen bonds through various supramolecular synthons, mostly in the absence of other stronger hydrogen bonds. Analysis of fluorine mediated interaction in the presence of strong hydrogen bonds has not been highlighted in detail. Hence a thorough structural investigation is needed to understand the role of "organic fluorine" in crystal engineering of small organic fluorinated molecules having the possibility of strong hydrogen bond formation in the solution and in the solid state. To fulfil this aim, we have synthesized a series of fluorinated amides using 3-methoxyphenylacetic acid and fluorinated anilines and studied their structural properties through single crystal and powder X-ray diffraction methods. Our results indicated that the "organic fluorine" plays a significant role in altering the packing characteristics of the molecule in building specific crystal lattices even in the presence of strong hydrogen bond.

Engineering Fluorometabolite Production: Fluorinase Expression in Salinispora tropica Yields Fluorosalinosporamide†

PubMed Central

Eustáquio, Alessandra S.; O'Hagan, David; Moore, Bradley S.

2010-01-01

Organofluorine compounds play an important role in medicinal chemistry where they are responsible for up to 15% of the pharmaceutical products on the market. While natural products are valuable sources of new chemical entities, natural fluorinated molecules are extremely rare and the pharmaceutical industry has not benefited from a microbial source of this class of compounds. Streptomyces cattleya is an unusual bacterium in that it elaborates fluoroacetate and the amino acid 4-fluorothreonine. The discovery in 2002 of the fluorination enzyme FlA responsible for C-F bond formation in S. cattleya, and its subsequent characterization, opened up for the first time the prospect of genetically engineering fluorometabolite production from fluoride ion in host organisms. As a proof of principle, we report here the induced production of fluorosalinosporamide by replacing the chlorinase gene salL from Salinispora tropica with the fluorinase gene flA. PMID:20085308

Organo-Lewis acids of enhanced utility, uses thereof, and products based thereon

DOEpatents

Marks, Tobin J.; Chen, You-Xian

2001-01-01

The organo-Lewis acids are novel triarylboranes which are highly fluorinated. Triarylboranes of one such type contain at least one ring substituent other than fluorine. These organoboranes have a Lewis acid strength essentially equal to or greater than that of the corresponding organoborane in which the substituent is replaced by fluorine, or have greater solubility in organic solvents. Another type of new organoboranes have 1-3 perfluorinated fused ring groups and 2-0 perfluorophenyl groups. When used as a cocatalyst in the formation of novel catalytic complexes with d- or f-block metal compounds having at least one leaving group such as a methyl group, these triorganoboranes, because of their ligand abstracting properties, produce corresponding anions which are capable of only weakly, if at all, coordinating to the metal center, and thus do not interfere in various polymerization processes such as are described.

Organo-Lewis acids of enhanced utility, uses thereof, and products based thereon

DOEpatents

Marks, Tobin J.; Chen, You-Xian

2002-01-01

The organo-Lewis acids are novel triarylboranes which are are highly fluorinated. Triarylboranes of one such type contain at least one ring substituent other than fluorine. These organoboranes have a Lewis acid strength essentially equal to or greater than that of the corresponding organoborane in which the substituent is replaced by fluorine, or have greater solubility in organic solvents. Another type of new organoboranes have 1-3 perfluorinated fused ring groups and 2-0 perfluorophenyl groups. When used as a cocatalyst in the formation of novel catalytic complexes with d- or f-block metal compounds having at least one leaving group such as a methyl group, these triorganoboranes, because of their ligand abstracting properties, produce corresponding anions which are capable of only weakly, if at all, coordinating to the metal center, and thus do not interfere in various polymerization processes such as are described.

Durable hydrophobic coating composition for metallic surfaces and method for the preparation of the composition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Jiong

A durable hydrophobic coating composition containing fluorinated silanes for metallic surfaces, such as stainless steel surfaces. The composition includes at least one fluorine-containing silane compound, at least one phosphorus-containing silane compound, and at least one hydrolysable compound. This coating is suitable for condenser tubes, among other applications, to promote dropwise condensation.

SEPARATION PROCESS FOR TRANSURANIC ELEMENT AND COMPOUNDS THEREOF

DOEpatents

Calvin, M.

1958-10-14

S> A process is presented for the separation of pluto nium from uranium and fission products in an aqueous acidic solution by use of a chelating agent. The plutonium is maintained in the tetravalent state and the uranium in the hexavalent state, and the acidic concentration is adjusted to about 1 N bar. The aqueous solution is then contacted with a water-immiscible organic solvent solution and the chelating agent. The chelating agents covered by this invention comprise a group of compounds characterized as fluorinated beta-diketones.

Process to prepare stable trifluorostyrene containing compounds grafted to base polymers using a solvent/water mixture

DOEpatents

Roelofs, Mark Gerrit; Yang, Zhen-Yu; Han, Amy Qi

2010-06-15

A fluorinated ion exchange polymer is prepared by grafting at least one grafting monomer derived from trifluorostyrene on to at least one base polymer in a organic solvent/water mixture. These ion exchange polymers are useful in preparing catalyst coated membranes and membrane electrode assemblies used in fuel cells.

Ionic Fluorine Chemistry.

DTIC Science & Technology

SOLID ROCKET OXIDIZERS, *LIQUID ROCKET OXIDIZERS, CHLORATES, FLUORIDES, ACETONES, CHLORINE COMPOUNDS, NITROSO COMPOUNDS, *HALOGEN COMPOUNDS, ADDITION REACTIONS, CESIUM COMPOUNDS, CHLORIDES, COMPLEX COMPOUNDS

[The effect of alternating administration of aluminum chloride and sodium fluoride in drinking water on the concentration of fluoride in serum and its content in bones of rats].

PubMed

Lubkowska, Anna; Chlubek, Dariusz; Machoy-Mokrzyniska, Anna

2006-01-01

Fluorine and aluminum remain a very interesting research topic due to equivocal and relatively unknown toxic action, role in the etiology of various diseases, and interactions of both elements. Fluorine and aluminum compounds are absorbed by organisms through the gastric and respiratory systems, although the latter route operates only at very high concentrations in air. Chronic exposure to fluorine and aluminum leads to accumulation of both elements, especially in bones and teeth, but also in lung, brain, kidney, and liver. Organisms excrete these elements with urine, faeces, and to a minor extent with sweat and bile. In the light of reports suggesting that aluminum has protective properties against fluorine toxicity during exposure to both elements, we decided to examine the effect of alternating doses of aluminum fluoride and sodium fluoride in drinking water on rats. Four female groups received: I--100 ppm fluorine ions during one month; II--100 ppm fluorine ions alternating every two days with 300 ppm aluminum ions during one month; III--100 ppm fluoride ions during four months; IV--100 ppm fluorine ions alternating every two days with 300 ppm aluminum ions during four months. The respective male groups called IA, IIA, IIIA, and IVA were treated identically. Subsequently, the animals were anesthetized and sacrificed. Blood was sampled from the heart and the right femur was removed for fluorine determination. Fluorine content in the femur and serum was determined with an ion-selective electrode (Orion). The results were analyzed statistically (Statistica 6). We observed higher fluoride concentrations in serum as compared with control values in all groups of female and male rats exposed to sodium fluoride only. Longer exposure time (4 months) did not result in further increase in serum fluoride concentration. However, longer exposure increased fluoride accumulation in the femur (p < 0.001). All groups exposed to NaF had significantly higher fluoride concentration in the femur as compared with control animals. Groups receiving NaF and AlCl3 showed lower fluoride concentration in serum and femur compared with those exposed to NaF only and higher in comparison with controls. Fluorine content in the femur of rats exposed to NaF and AlCI3 for four months was similar to the results obtained after one month of exposure.

Adsorption mechanism of different organic chemicals on fluorinated carbon nanotubes.

PubMed

Li, Hao; Zheng, Nan; Liang, Ni; Zhang, Di; Wu, Min; Pan, Bo

2016-07-01

Multi-walled carbon nanotubes (MC) were fluorinated by a solid-phase reaction method using polytetrafluoroethylene (PTFE). The surface alteration of carbon nanotubes after fluorination (MC-F) was confirmed based on surface elemental analysis, TEM and SEM. The incorporation of F on MC surface was discussed as F incorporation on carbon defects, replacement of carboxyl groups, as well as surface coating of PTFE. The adsorption performance and mechanisms of MC-F for five kinds of representative organic compounds: sulfamethoxazole (SMX), ofloxacin (OFL), norfloxacin (NOR), bisphenol a (BPA) and phenanthrene (PHE) were investigated. Although BET-N2 surface area of the investigated CNTs decreased after fluorination, the adsorption of all five chemicals increased. Because of the glassification of MC-F surface coating during BET-N2 surface area measurement, the accessible surface area of MC-F was underestimated. Desorption hysteresis was generally observed in all the sorption systems in this study, and the desorption hysteresis of MC-F were stronger than the pristine CNTs. The enhanced adsorption of MC-F may be attributed the pores generated on the coated PTFE and the dispersed CNT aggregates due to the increased electrostatic repulsion after fluorination. The rearrangement of the bundles or diffusion of the adsorbates in MC-F inner pores were the likely reason for the strong desorption hysteresis of MC-F. The butterfly structure of BPA resulted in its high sorption and strong desorption hysteresis. The exothermic sorption character of OFL on CNTs resulted in its strong desorption hysteresis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Aromatic fluorine compounds. II. 1,2,4,5-Tetrafluorobenzene and related compounds

USGS Publications Warehouse

Finger, G.C.; Reed, F.H.; Burness, D.M.; Fort, D.M.; Blough, R.R.

1951-01-01

The synthesis and properties of 1,2,4,5-tetrafluorobenzene and a group of bromofluoro and chlorofluorobenzenes with a predominating 1,2,4,5-structure are described. Flash point and surface tension data for the fluorinated benzenes and the influence of chlorine substitution upon these values were studied. Under nitration conditions, 1,2,4,5-tetrafluorobenzene will not form a nitro derivative, but will undergo a preferential 1,4-fluorine displacement-oxidation mechanism to give 2,5-difluoro-1,4-benzoquinone. Diazotization reactions on 2-nitro-3,4,6-trifluoroaniline reveal that the nitro group or a fluorine atom in the 4- or 6-position may become labilized, under certain conditions, and undergo replacement.

Synthesis of novel fluorinated chalcones derived from 4‧-morpholinoacetophenone and their antiproliferative effects

NASA Astrophysics Data System (ADS)

Kurşun Aktar, Bedriye Seda; Oruç-Emre, Emine Elçin; Demirtaş, Ibrahim; Yaglioglu, Ayse Sahin; Guler, Caglar; Adem, Sevki; Karaküçük Iyidoğan, Ayşegül

2017-12-01

The fluorinated chalcones were synthesized by Claisen-Schmidt condensation between 4‧-morpholineacetophenone and various fluorinated benzaldehydes in the presence of NaOH in methanol. The synthesized compounds [1-7] were evaluated their antiproliferative activity against HeLa and C6 cell lines. Among them, compounds 4 and 5 were determined to have anticancer activity against HeLa cells line (IC50 values of 7.74 and 6.10 μg/mL, respectively). The anticancer activity results were shown that compounds 3, and 6 had inhibitory against C6 cells (IC50 values of 12.80 and 4.16 μg/mL, respectively). The compounds 1 and 2 had high antiproliferative activity with non-cytotoxicity. All of the new compounds, except for compound 4 showed inhibition against the human isozyme hCA I with IC50 in the range of 0.5-1,16 mM. Pyruvate kinase M2 (PKM2) was effectively inhibited by compound 4 with IC50 = 26 μM.

Materials for n-type organic electronics: synthesis and properties of fluoroarene-thiophene semiconductors

NASA Astrophysics Data System (ADS)

Facchetti, Antonio; Yoon, Myung-Han; Katz, Howard E.; Marks, Tobin J.

2003-11-01

Recent progress in the field of organic electronics is due to a fruitful combination of both innovative molecular design and promising low-cost material/device assembly. Targeting the first strategy, we present here the general synthesis of fluoroarene-containing thiophene-based semiconductors and the study of their properties with respect to the corresponding fluorine-free hole-transporting analogues. The new compounds have been characterized by elemental analysis, mass spectrometry, and 1H- and 19F NMR. The dramatic influence of fluorine substitution and molecular architecture has been investigated by solution/film optical absorption, fluorescence emission, and cyclic voltammetry. Single crystal data for all of the oligomers have been obtained and will be presented. Film microstructure and morphology of this new class of materials have been studied by XRD and SEM. Particular emphasis will be posed on the solution-processable oligomers and polymers.

Nanoscale organization in the fluorinated room temperature ionic liquid: Tetraethyl ammonium (trifluoromethanesulfonyl)(nonafluorobutylsulfonyl)imide

NASA Astrophysics Data System (ADS)

Lo Celso, F.; Appetecchi, G. B.; Jafta, C. J.; Gontrani, L.; Canongia Lopes, J. N.; Triolo, A.; Russina, O.

2018-05-01

Fluorinated Room Temperature Ionic Liquids (FRTILs) are a branch of ionic liquids that is the object of growing interest for a wide range of potential applications, due to the synergic combination of specifically ionic features and those properties that stem from fluorous tails. So far limited experimental work exists on the micro- and mesoscopic structural organization in this class of compounds. Such a work is however necessary to fully understand morphological details at atomistic level that would have strong implications in terms of bulk properties. Here we use the synergy between X-ray and neutron scattering together with molecular dynamics simulations to access structural details of a technologically relevant FRTIL that is characterised by an anion bearing a long enough fluorinated tail to develop specific morphological features. In particular, we find the first experimental evidence that in FRTILs bearing an asymmetric bis(perfluoroalkyl)sulfonyl-imide anion, fluorous side chains tend to be spatially segregated into nm-scale spatial heterogeneities. This feature together with the well-established micro-segregation of side alkyl chains in conventional RTILs leads to the concept of triphilic ILs, whose technological applications are yet to be fully developed.

Methods to Increase the Metabolic Stability of (18)F-Radiotracers.

PubMed

Kuchar, Manuela; Mamat, Constantin

2015-09-03

The majority of pharmaceuticals and other organic compounds incorporating radiotracers that are considered foreign to the body undergo metabolic changes in vivo. Metabolic degradation of these drugs is commonly caused by a system of enzymes of low substrate specificity requirement, which is present mainly in the liver, but drug metabolism may also take place in the kidneys or other organs. Thus, radiotracers and all other pharmaceuticals are faced with enormous challenges to maintain their stability in vivo highlighting the importance of their structure. Often in practice, such biologically active molecules exhibit these properties in vitro, but fail during in vivo studies due to obtaining an increased metabolism within minutes. Many pharmacologically and biologically interesting compounds never see application due to their lack of stability. One of the most important issues of radiotracers development based on fluorine-18 is the stability in vitro and in vivo. Sometimes, the metabolism of (18)F-radiotracers goes along with the cleavage of the C-F bond and with the rejection of [(18)F]fluoride mostly combined with high background and accumulation in the skeleton. This review deals with the impact of radiodefluorination and with approaches to stabilize the C-F bond to avoid the cleavage between fluorine and carbon.

Free variable selection QSPR study to predict 19F chemical shifts of some fluorinated organic compounds using Random Forest and RBF-PLS methods

NASA Astrophysics Data System (ADS)

Goudarzi, Nasser

2016-04-01

In this work, two new and powerful chemometrics methods are applied for the modeling and prediction of the 19F chemical shift values of some fluorinated organic compounds. The radial basis function-partial least square (RBF-PLS) and random forest (RF) are employed to construct the models to predict the 19F chemical shifts. In this study, we didn't used from any variable selection method and RF method can be used as variable selection and modeling technique. Effects of the important parameters affecting the ability of the RF prediction power such as the number of trees (nt) and the number of randomly selected variables to split each node (m) were investigated. The root-mean-square errors of prediction (RMSEP) for the training set and the prediction set for the RBF-PLS and RF models were 44.70, 23.86, 29.77, and 23.69, respectively. Also, the correlation coefficients of the prediction set for the RBF-PLS and RF models were 0.8684 and 0.9313, respectively. The results obtained reveal that the RF model can be used as a powerful chemometrics tool for the quantitative structure-property relationship (QSPR) studies.

Enantioselective aldol reactions with masked fluoroacetates

NASA Astrophysics Data System (ADS)

Saadi, Jakub; Wennemers, Helma

2016-03-01

Despite the growing importance of organofluorines as pharmaceuticals and agrochemicals, the stereoselective introduction of fluorine into many prominent classes of natural products and chemotherapeutic agents is difficult. One long-standing unsolved challenge is the enantioselective aldol reaction of fluoroacetate to enable access to fluorinated analogues of medicinally relevant acetate-derived compounds, such as polyketides and statins. Herein we present fluoromalonic acid halfthioesters as biomimetic surrogates of fluoroacetate and demonstrate their use in highly stereoselective aldol reactions that proceed under mild organocatalytic conditions. We also show that the methodology can be extended to formal aldol reactions with fluoroacetaldehyde and consecutive aldol reactions. The synthetic utility of the fluorinated aldol products is illustrated by the synthesis of a fluorinated derivative of the top-selling drug atorvastatin. The results show the prospects of the method for the enantioselective introduction of fluoroacetate to access a wide variety of highly functionalized fluorinated compounds.

Effect of fluroine content, atmosphere, and burnishing technique on the lubricating properties of graphite fluoride

NASA Technical Reports Server (NTRS)

Fusaro, R. L.

1974-01-01

Eight different graphite fluoride compounds with fluorine to carbon ratios varying from x = 0.25 to 1.1 were evaluated as burnished films in order to determine the effect of fluorine content on the solid lubricant properties of graphite fluoride. For comparison, similar experiments were conducted on graphite burnished films. It was found that even a small amount of fluorine in graphite fluoride (CF0.25)n improved the lubricating properties of graphite. However, such factors as burnishing atmosphere, burnishing technique, test atmosphere, and specimen temperature affected the results as much as varying the fluorine to carbon ratio of the compound. Best life was found for films that were machined burnished in moist air and tested in moist air.

Identification and characterization of conservative organic tracers for use as hydrologic tracers for the Yucca Mountain site characterization study. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stetzenbach, K.; Farnham, I.

1996-06-01

Extensive tracer testing is expected to take place at the C-well complex in the Nevada Test Site as part of the Yucca Mountain Site Characterization Project. The C-well complex consists of one pumping well, C3, and two injection wells, C1 and C2 into which tracer will be introduced. The goal of this research was to provide USGS with numerous tracers to completed these tests. Several classes of fluorinated organic acids have been evaluated. These include numerous isomers of fluorinated benzoic acids, cinnamic acids, and salicylic acids. Also several derivatives of 2-hydroxy nicotinic acid (pyridone) have been tested. The stability ofmore » these compounds was determined using batch and column tests. Ames testing (mutagenicity/carcinogenicity) was conducted on the fluorinated benzoic acids and a literature review of toxicity of the fluorobenzoates and three perfluoro aliphatic acids was prepared. Solubilities were measured and method development work was performed to optimize the detection of these compounds. A Quality Assurance (QA) Program was developed under existing DOE and USGS guidelines. The program includes QA procedures and technical standard operating procedures. A tracer test, using sodium iodide, was performed at the C-well complex. HRC chemists performed analyses on site, to provide real time data for the USGS hydrologists and in the laboratories at UNLV. Over 2,500 analyses were performed. This report provides the results of the laboratory experiments and literature reviews used to evaluate the potential tracers and reports on the results of the iodide C-well tracer test.« less

X-ray photoelectron spectroscopy as detection tool for coordinated or uncoordinated fluorine atoms demonstrated on fluoride systems NaF, K2TaF7, K3TaF8, K2ZrF6, Na7Zr6F31 and K3ZrF7

NASA Astrophysics Data System (ADS)

Boča, Miroslav; Barborík, Peter; Mičušík, Matej; Omastová, Mária

2012-07-01

While systems K3TaF8 and K3ZrF7 were prepared by modified molten salt method modified wet pathway was used for reproducible preparation of Na7Zr6F31. Its congruently melting character was demonstrated on simultaneous TG/DSC measurements and XRD patterns. X-ray photoelectron spectroscopy was applied for identification of differently bonded fluorine atoms in series of compounds NaF, K2TaF7, K3TaF8, K2ZrF6, Na7Zr6F31 and K3ZrF7. Three different types of fluorine atoms were described qualitatively and quantitatively. Uncoordinated fluorine atoms (F-) provide signals at lowest binding energies, followed by signals from terminally coordinated fluorine atoms (M-F) and then bridging fluorine atoms (M-F-M) at highest energy. Based on XPS F 1s signals assigned to fluorine atoms in compounds with correctly determined structure it was suggested that fluorine atoms in K3ZrF7 have partially bridging character.

Fluorine Compounds and Dental Health: Applications of General Chemistry Topics

ERIC Educational Resources Information Center

Pinto, Gabriel

2009-01-01

An example about the use of everyday phenomena in teaching general chemistry is given. Students have a greater appreciation of the principles of chemistry if they can see the relevance to their lives. Fluorine compounds in dental applications (as topical or as systemic use) provide an excellent context in which to review core content of general…

Strategic incorporation of fluorine in the drug discovery of new-generation antitubercular agents targeting bacterial cell division protein FtsZ⋆

PubMed Central

Ojima, Iwao; Awasthi, Divya; Wei, Longfei; Haranahalli, Krupanandan

2016-01-01

This article presents an account of our research on the discovery and development of new-generation fluorine-containing antibacterial agents against drug-resistant tuberculosis, targeting FtsZ. FtsZ is an essential protein for bacterial cell division and a highly promising therapeutic target for antibacterial drug discovery. Through design, synthesis and semi-HTP screening of libraries of novel benzimidazoles, followed by SAR studies, we identified highly potent lead compounds. However, these lead compounds were found to lack sufficient metabolic and plasma stabilities. Accordingly, we have performed extensive study on the strategic incorporation of fluorine into lead compounds to improve pharmacological properties. This study has led to the development of highly efficacious fluorine-containing benzimidazoles as potential drug candidates. We have also performed computational docking analysis of these novel FtsZ inhibitors to identify their putative binding site. Based on the structural data and docking analysis, a plausible mode-of-action for this novel class of FtsZ inhibitors is proposed. PMID:28555087

Antimicrobial and anticancer activity of some novel fluorinated thiourea derivatives carrying sulfonamide moieties: synthesis, biological evaluation and molecular docking.

PubMed

Ghorab, Mostafa M; Alsaid, Mansour S; El-Gaby, Mohamed S A; Elaasser, Mahmoud M; Nissan, Yassin M

2017-04-07

Various thiourea derivatives have been used as starting materials for compounds with better biological activities. Molecular modeling tools are used to explore their mechanism of action. A new series of thioureas were synthesized. Fluorinated pyridine derivative 4a showed the highest antimicrobial activity (with MIC values ranged from 1.95 to 15.63 µg/mL). Interestingly, thiadiazole derivative 4c and coumarin derivative 4d exhibited selective antibacterial activities against Gram positive bacteria. Fluorinated pyridine derivative 4a was the most active against HepG2 with IC50 value of 4.8 μg/mL. Molecular docking was performed on the active site of MK-2 with good results. Novel compounds were obtained with good anticancer and antibacterial activity especially fluorinated pyridine derivative 4a and molecular docking study suggest good activity as mitogen activated protein kinase-2 inhibitor. Graphical abstract Compound 4a in the active site of MK-2.

Fluorine in psychedelic phenethylamines.

PubMed

Trachsel, Daniel

2012-01-01

The so-called psychedelic phenethylamines represent a class of drugs with a large range of psychoactive properties in humans, ranging from naturally occurring mescaline to amphetamine analogues and homologues. The interest in many of these compounds, occasionally referred to as designer-drugs, is widely dispersed across popular culture and political and scientific communities. In recent decades, fluorine has become a powerful and important tool in medicinal chemistry. In addition, fluorine-containing compounds and medicines can be found in numerous commercially successful pharmaceuticals that have gained a market share of some 5-15%. One might anticipate this trend to increase in the future. As far as fluorinated phenethylamines are concerned, much less is known about their chemistry and pharmacology. This paper provides an overview regarding the biological properties of over 60 fluorinated phenethylamines and discusses both historical and recent chemistry-related developments. It was shown that the introduction of fluorine into the phenethylamine nucleus can impact greatly on psychoactivity of these compounds, ranging from marked loss to enhancement and prolongation of effects. For example, in contrast to the psychoactive escaline (70), it was observed that its fluoroescaline (76) counterpart was almost devoid of psychoactive effects. Difluoroescaline (77), on the other hand, retained, and trifluoroescaline (78) showed increased human potency of escaline (70). Difluoromescaline (72) and trifluoromescaline (73) increasingly surpassed human potency and duration of mescaline (22) effects. Copyright © 2012 John Wiley & Sons, Ltd.

High-Temperature Syntheses of New, Thermally-Stable Chemical Compounds.

DTIC Science & Technology

SYNTHESIS(CHEMISTRY), HEAT RESISTANT PLASTICS, NITRILES, FLUORINE COMPOUNDS, COMPLEX COMPOUNDS, NITROGEN, SULFIDES, ORGANOMETALLIC COMPOUNDS, ORGANOBORANES, BORIDES, SPINEL, CARBIDES, NITRIDES, SILICIDES .

Tunable Cascade Reaction of Aryl Diazonium Salts and Trialkylamine: Synthesis of Monofluorinated Arylhydrazones and gem-Difluorinated Azo Compounds.

PubMed

Guo, Rui; Zhang, Zhengjuan; Shi, Feng; Tang, Pingping

2016-03-04

The first example of a mild and tunable cascade reaction of aryl diazonium salts and trialkylamine in the presence of Selectfluor to prepare monofluorinated arylhydrazones and gem-difluorinated azo compounds without metal has been explored. In the presence of H2O, the monofluorinated arylhydrazones were observed in moderate to good yield. In the absence of H2O, the gem-difluorinated azo compounds were obtained. The fluorinated arylhydrazones were utilized to synthesize fluorinated pyrazoles and other nitrogen-containing compounds.

Chemical vapor deposition of fluorine-doped zinc oxide

DOEpatents

Gordon, Roy G.; Kramer, Keith; Liang, Haifan

2000-06-06

Fims of fluorine-doped zinc oxide are deposited from vaporized precursor compounds comprising a chelate of a dialkylzinc, such as an amine chelate, an oxygen source, and a fluorine source. The coatings are highly electrically conductive, transparent to visible light, reflective to infrared radiation, absorbing to ultraviolet light, and free of carbon impurity.

THE PHASE BEHAVIOR OF FLUORINATED DIOLS, DIVINYL ADIPATE, AND A FLUORINATED POLYESTER IN SUPERCRITICAL CARBON DIOXIDE. (R828131)

EPA Science Inventory

The use of supercritical carbon dioxide as a reaction medium for polyester synthesis is hindered by the low solubility of diols in CO₂. However, it has been previously demonstrated that fluorinated compounds can exhibit greater miscibility with carbon dioxide than t...

Geminal difunctionalization of α-diazo arylmethylphosphonates: synthesis of fluorinated phosphonates.

PubMed

Zhou, Yujing; Zhang, Yan; Wang, Jianbo

2016-11-08

A general approach towards diverse fluorinated phosphonates via geminal difunctionalization reactions of α-diazo arylmethylphosphonates is described. The diazo functionality (RR'C[double bond, length as m-dash]N 2 ) is successfully converted to RR'CF 2 , RR'CHF, RR'CFBr or RR'CFNR'' 2 groups by employing different fluorination reagents. A variety of fluorinated organophosphorus compounds were readily accessed in good to excellent yields from a common type of precursor.

The relationship between the chemical structure and neurotoxicity of alkyl organophosphorus compounds

PubMed Central

Davies, D. R.; Holland, P.; Rumens, M. J.

1960-01-01

Thirty-six alkyl organophosphorus compounds have been tested for neurotoxicity in the chicken. The individual compounds were chosen to enable the importance of each portion of the molecule to be assessed in relation to the property of neurotoxicity. Seventeen substances were found to be neurotoxic, fifteen for the first time. All of these contained fluorine. On the basis of the results reported, certain predictions have been made about the chemical structure of compounds which would be expected to be neurotoxic. The importance of fluorine suggests that it plays a direct role in the development of the biochemical lesion, and this may occur as the result of its being carried by the molecule as a whole to specific areas in the nervous system. By the action of cholinesterase, the P-F bond may be ruptured and ionic fluorine liberated where it blocks some metabolic cycle. PMID:13814387

Scientific Assessment of Stratospheric Ozone: 1989, volume 2. Appendix: AFEAS Report

NASA Technical Reports Server (NTRS)

1990-01-01

The results are presented of the Alternative Fluorocarbon Environmental Acceptability Study (AFEAS), which was organized to evaluate the potential effects on the environment of alternate compounds targeted to replace fully halogenated chlorofluorocarbons (CFCs). All relevant current scientific information to determine the environmental acceptability of the alternative fluorocarbons. Special emphasis was placed on: the potential of the compounds to affect stratospheric ozone; their potential to affect tropospheric ozone; their potential to contribute to model calculated global warming; the atmospheric degradation mechanisms of the compounds, in order to identify their products; and the potential environmental effects of the decomposition products. The alternative compounds to be studied were hydrofluorocarbons (HFCs) with one or two carbon atoms and one or more each of fluorine and hydrogen.

Behavioral and neurosensory responses of the boll weevil,Anthonomus grandis Boh. (Coleoptera: Curculionidae), to fluorinated analogs of aldehyde components of its pheromone.

PubMed

Dickens, J C; Prestwich, G D; Sun, W C

1991-06-01

Competitive field tests with α-fluorinated analogs of compounds III and IV (III-α-F and IV-α-F, respectively) of the boll weevil,Anthonomus grandis Boh., aggregation pheromone showed these compounds, when combined with the other pheromone components [(±)-I and II], to be as attractive as grandlure [(+)-I, II, and III+IV]. Dose-response curves constructed from electroantennograms of male boll weevils to serial stimulus loads of III, IV, III-α-F, IV-α-F, and the corresponding acyl fluorinated analogs (III-acyl-F and IV-acyl-F) showed the α-fiuorinated analogs to be as active as the pheromone components (threshold=0.1 μg), while the acyl fluorinated analogs had a 10-100 x higher threshold (=1-10 μg). Single-neuron recordings showed that IV neurons and II neurons (Dickens, 1990) responded to IV-α-F and III-α-F, respectively, while IV-acyl-F and III-acyl-F were inactive. Since a previous study showed compounds I, II, and IV to be essential for behavioral responses in the field, it seems likely that the activity of the α-fluorinated analogs observed here is due to the stimulation of IV neurons by IV-α-F as indicated in single neuron recordings.

Pyridine radical cation and its fluorine substituted derivatives

USGS Publications Warehouse

Bondybey, V.E.; English, J.H.; Shiley, R.H.

1982-01-01

The spectra and relaxation of the pyridine cation and of several of its fluorinated derivatives are studied in low temperature Ne matrices. The ions are generated by direct photoionization of the parent compounds. Of the compounds studied, laser induced → and → fluorescence is observed only for the 2, 6‐difluoropyridine cation. The analysis of the spectrum indicates that the ion is planar both in the and states. The large variety in the spectroscopic and relaxation behavior of fluoropyridine radical cations is explained in terms of their electronic structure and of the differential shifts of the individual electronic states caused by the fluorine substitution.

Fluorinated elastomeric materials

DOEpatents

Lagow, Richard J.; Dumitru, Earl T.

1986-11-04

This invention relates to a method of making perfluorinated elastomeric materials, and to materials made by such methods. In the full synthetic scheme, a partially fluorinated polymeric compound, with moieties to prevent crystallization, is created. It is then crosslinked to a desired degree, then perfluorinated. Various intermediate materials, such as partially fluorinated crosslinked polymers, have useful properties, and are or may become commercially available. One embodiment of this invention therefore relates to perfluorination of a selected partially fluorinated, crosslinked material, which is one step of the full synthetic scheme.

Fluorinated elastomeric materials

DOEpatents

Lagow, Richard J.; Dumitru, Earl T.

1990-02-13

This invention relates to a method of making perfluorinated elastomeric materials, and to materials made by such methods. In the full synthetic scheme, a partially fluorinated polymeric compound, with moieties to prevent crystallization, is created. It is then crosslinked to a desired degree, then perfluorinated. Various intermediate materials, such as partially fluorinated crosslinked polymers, have useful properties, and are or may become commercially available. One embodiment of this invention therefore relates to perfluorination of a selected partially fluorinated, crosslinked material, which is one step of the full synthetic scheme.

Name that compound: The numbers game for CFCs, HFCs, HCFCs, and Halons

DOE Data Explorer

Blasing, T. J.; Jones, Sonja

2012-02-01

Chlorofluorocarbons (CFCs) contain Carbon and some combination of Fluorine and Chlorine atoms. Hydrofluorocarbons (HFCs) contain Hydrogen, Fluorine, and Carbon (no chlorine). Hydrochlorofluorocarbons (HCFCs) contain Hydrogen, Chlorine, Fluorine, and Carbon atoms. Hydrobromofluorocarbons (HBFCs) contain Hydrogen, Bromine, Fluorine, and Carbon atoms. Perfluorocarbons contain Fluorine, Carbon, and Bromine atoms, and some contain Chlorine and/or Hydrogen atoms. These compounds are often designated by a combination of letters and numbers (e.g., CFC-11, HCFC-142b). In the latter example, the lower-case b refers to an isomer, which has no relationship to the chemical formula (C2H3F2Cl), but designates a particular structural arrangement of the atoms included. For example, HCFC-142b identifies the isomer in which all three hydrogen atoms are attached to the same carbon atom, and the structural formula is written as CH3CF2Cl. By contrast, HCFC-142 (without the b) refers to an arrangement in which one carbon atom is attached to two hydrogen atoms and one chlorine atom, while the other carbon atom is attached to the third hydrogen atom and two fluorine atoms. Hence, it has a different structural formula (CH2ClCHF2).

Diastereocontrolled Electrophilic Fluorinations of 2-Deoxyribonolactone: Syntheses of All Corresponding 2-Deoxy-2-fluoro-lactones and 2’-Deoxy-2’-fluoro-NAD+s

PubMed Central

Cen, Yana; Sauve, Anthony A.

2009-01-01

Methods to construct 2’-deoxy-2’-fluoro-nucleosides have undergone limited improvement in the last twenty years in spite of substantially increased value of these compounds as pharmaceuticals and as tools for studying biological processes. We herein describe a consolidated approach to synthesize precursors to these commercially and scientifically valuable compounds via diastereocontrolled fluorination of the readily available precursor 2-deoxy-d-ribonolactone. With employment of appropriate sterically bulky silyl protecting groups at 3 and 5 positions, controlled electrophilic fluorination of the Li-ribonolactone enolate by N-fluorodibenezenesulfonamide yielded the corresponding 2-deoxy-2-fluoro-arabino-lactone in high isolated yield (72 %). The protected 2-deoxy-2, 2-difluoro-ribonolactone was obtained similarly in high yield from a second round of electrophilic fluorination (2 steps, 51% from protected ribonolactone starting material). Accomplishment of the difficult ribo-fluorination of the lactone was achieved by the directive effects of a diastereoselectively installed α-trimethylsilyl group. Electrophilic fluorination of a protected 2-deoxy-2-trimethylsilyl-arabino-lactone via enolate generation provided the protected 2-deoxy-2-fluoro-ribo-lactone as the exclusive fluorinated product. The reaction also yielded the starting material, the desilylated protected 2-deoxy-ribonolactone, which was recycled to provide a 38% chemical yield of the fluorinated product (versus initial protected ribonolactone) after consecutive silylation and fluorination cycles. Using our fluorinated sugar precursors we prepared the 2’-fluoro-arabino-, 2’-fluoro-ribo- and 2’,2’-difluoro-nicotinamide adenine dinucleotides (NAD+) of potential biological interest. These syntheses provide the most consolidated and efficient methods for production of sugar precursors of 2’-deoxy-2’-fluoronucleosides and have the advantage of utilizing an air-stable electrophilic fluorinating agent. The fluorinated NAD+s are anticipated to be useful for studying a variety of cellular metabolic and signaling processes. PMID:19958035

Fluorine compounds for doping conductive oxide thin films

DOEpatents

Gessert, Tim; Li, Xiaonan; Barnes, Teresa M; Torres, Jr., Robert; Wyse, Carrie L

2013-04-23

Methods of forming a conductive fluorine-doped metal oxide layer on a substrate by chemical vapor deposition are described. The methods may include heating the substrate in a processing chamber, and introducing a metal-containing precursor and a fluorine-containing precursor to the processing chamber. The methods may also include adding an oxygen-containing precursor to the processing chamber. The precursors are reacted to deposit the fluorine-doped metal oxide layer on the substrate. Methods may also include forming the conductive fluorine-doped metal oxide layer by plasma-assisted chemical vapor deposition. These methods may include providing the substrate in a processing chamber, and introducing a metal-containing precursor, and a fluorine-containing precursor to the processing chamber. A plasma may be formed that includes species from the metal-containing precursor and the fluorine-containing precursor. The species may react to deposit the fluorine-doped metal oxide layer on the substrate.

Fluorine walk: The impact of fluorine in quinolone amides on their activity against African sleeping sickness.

PubMed

Berninger, Michael; Erk, Christine; Fuß, Antje; Skaf, Joseph; Al-Momani, Ehab; Israel, Ina; Raschig, Martina; Güntzel, Paul; Samnick, Samuel; Holzgrabe, Ulrike

2018-05-25

Human African Trypanosomiasis, also known as African sleeping sickness, is caused by the parasitic protozoa of the genus Trypanosoma. If there is no pharmacological intervention, the parasites can cross the blood-brain barrier (BBB), inevitably leading to death of the patients. Previous investigation identified the quinolone amide GHQ168 as a promising lead compound having a nanomolar activity against T. b. brucei. Here, the role of a fluorine substitution at different positions was investigated in regard to toxicity, pharmacokinetics, and antitrypanosomal activity. This 'fluorine walk' led to new compounds with improved metabolic stability and consistent activity against T. b. brucei. The ability of the new quinolone amides to cross the BBB was confirmed using an 18 F-labelled quinolone amide derivative by means of ex vivo autoradiography of a murine brain. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Improved performance of lithium–sulfur battery with fluorinated electrolyte

DOE Office of Scientific and Technical Information (OSTI.GOV)

Azimi, Nasim; Weng, Wei; Takoudis, Christos

An organo-fluorine compound, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), was investigated for the first time as the electrolyte solvent in the lithium–sulfur battery. The new fluorinated electrolyte suppressed the deleterious shuttling effect and improved the capacity retention and coulombic efficiency in cell tests. In addition, it was found to eliminate the self-discharge of the lithium–sulfur battery.

Internal energy deposition with silicon nanoparticle-assisted laser desorption/ionization (SPALDI) mass spectrometry

NASA Astrophysics Data System (ADS)

Dagan, Shai; Hua, Yimin; Boday, Dylan J.; Somogyi, Arpad; Wysocki, Ronald J.; Wysocki, Vicki H.

2009-06-01

The use of silicon nanoparticles for laser desorption/ionization (LDI) is a new appealing matrix-less approach for the selective and sensitive mass spectrometry of small molecules in MALDI instruments. Chemically modified silicon nanoparticles (30 nm) were previously found to require very low laser fluence in order to induce efficient LDI, which raised the question of internal energy deposition processes in that system. Here we report a comparative study of internal energy deposition from silicon nanoparticles to previously explored benzylpyridinium (BP) model compounds during LDI experiments. The internal energy deposition in silicon nanoparticle-assisted laser desorption/ionization (SPALDI) with different fluorinated linear chain modifiers (decyl, hexyl and propyl) was compared to LDI from untreated silicon nanoparticles and from the organic matrix, [alpha]-cyano-4-hydroxycinnamic acid (CHCA). The energy deposition to internal vibrational modes was evaluated by molecular ion survival curves and indicated that the ions produced by SPALDI have an internal energy threshold of 2.8-3.7 eV. This is slightly lower than the internal energy induced using the organic CHCA matrix, with similar molecular survival curves as previously reported for LDI off silicon nanowires. However, the internal energy associated with desorption/ionization from the silicon nanoparticles is significantly lower than that reported for desorption/ionization on silicon (DIOS). The measured survival yields in SPALDI gradually decrease with increasing laser fluence, contrary to reported results for silicon nanowires. The effect of modification of the silicon particle surface with semifluorinated linear chain silanes, including fluorinated decyl (C10), fluorinated hexyl (C6) and fluorinated propyl (C3) was explored too. The internal energy deposited increased with a decrease in the length of the modifier alkyl chain. Unmodified silicon particles exhibited the highest analyte internal energy deposition. These findings may suggest a role of the modifier as a moderator in the energy dissipation and relaxation process. The relatively low internal energy content of SPALDI-produced ions indicates that this is a "soft" desorption technique, with potential advantages in the analysis of labile compounds.

(Polyfluoroaryl) fluoroanions of aluminum, gallium, and indium of enhanced utility, uses thereof, and products based thereon

DOEpatents

Marks, Tobin J.; Chen, You-Xian

2001-01-01

The (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are novel weakly coordinating anions which are highly fluorinated. (Polyfluoroaryl)fluoroanions of one such type contain at least one ring substituent other than fluorine. These (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium have greater solubility in organic solvents, or have a coordinative ability essentially equal to or less than that of the corresponding (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium in which the substituent is replaced by fluorine. Another type of new (polyfluoroaryl)fluoroanion of aluminum, gallium, and indium have 1-3 perfluorinated fused ring groups and 2-0 perfluorophenyl groups. When used as a cocatalyst in the formation of novel catalytic complexes with d- or f-block metal compounds having at least one leaving group such as a methyl group, these anions, because of their weak coordination to the metal center, do not interfere in the ethylene polymerization process, while affecting the propylene process favorably, if highly isotactic polypropylene is desired. Thus, the (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of this invention are useful in various polymerization processes such as are described.

(Polyfluoroaryl) fluoroanions of aluminum, gallium, and indium of enhanced utility, uses thereof, and products based thereon

DOEpatents

Marks, Tobin J.; Chen, You-Xian

2002-01-01

The (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are novel weakly coordinating anions which are highly fluorinated. (Polyfluoroaryl)fluoroanions of one such type contain at least one ring substituent other than fluorine. These (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium have greater solubility in organic solvents, or have a coordinative ability essentially equal to or less than that of the corresponding (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium in which the substituent is replaced by fluorine. Another type of new (polyfluoroaryl)fluoroanion of aluminum, gallium, and indium have 1-3 perfluorinated fused ring groups and 2-0 perfluorophenyl groups. When used as a cocatalyst in the formation of novel catalytic complexes with d- or f-block metal compounds having at least one leaving group such as a methyl group, these anions, because of their weak coordination to the metal center, do not interfere in the ethylene polymerization process, while affecting the propylene process favorably, if highly isotactic polypropylene is desired. Thus, the (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of this invention are useful in various polymerization processes such as are described.

Atmosphere purification of radon and radon daughter elements

DOEpatents

Stein, L.

1974-01-01

A method of removing radon and radon daughter elements from an atmosphere containing these elements by passing the atmosphere through a bed of fluorinating compound whereby the radon and radon daughters are oxidized to their respective fluorides is discussed. These fluorides adhere to the fluorinating compound and are thus removed from the atmosphere which may then be recirculated. A method for recovering radon and separating radon from its daughter elements is also described. (Official Gazette)

Oxidation of dimethyl-ether and ethylene in the atmosphere and combustion environment and thermodynamic studies on hydrofluorocarbons usingab initio calculation methods

NASA Astrophysics Data System (ADS)

Yamada, Takahiro

1999-08-01

Reaction pathways and kinetics are analyzed on CH3OC.H2 unimolecular decay and on the complete CH3OC.H2 + O2 reaction system using thermodynamic properties DHdegf 298,Sdeg 298, and Cp(T) 300 <= T/K <= 1500) derived by two ab initio calculation methods, CBS-q and G2. These are used to determine thermodynamic properties of reactants, intermediate radicals and transition state (TS) compounds. Quantum Rice-Ramsperger-Kassel (QRRK) analysis is used to calculate energy dependent rate constants, k(E), and master equation is used to account for collisional stabilization. Comparison of calculated fall-off with experiment indicates that the CBS-q and G2 calculated Ea,rxn for the rate controlling transition state (β-scission reaction to CH 2O + C.H2OOH) needs to be lowered by factor of 3.3 kcal/mol and 4.0 kcal/mol respectively in order to match the data of Sehested et al. Experimental results on dimethyl-ether pyrolysis and oxidation reaction systems are compared with a detailed reaction mechanism model. The computer code CHEMKIN II is used for numerical integration. Overall agreement of the model data with experimental data is very good. Reaction pathways are analyzed and kinetics are determined on formation and reactions of the adduct resulting from OH addition to ethylene using the above ab initio methods. Hydrogen atom tunneling is included by use of Eckart formalism. Rate constants are compared with experimentally determined product branching ratios (C.H2CH 2OH stabilization: CH2O + CH3: CH3CHO + H). ab initio calculations are performed to estimate thermodynamic properties of nine fluorinated ethane compounds (fluoroethane to hexafluoroethane), eight fluoropropane (1-fluoropropane, 1,1- and 1,2- difluoropropane, 1,1,1- and 1,1,2-trifluoropropane, 1,1,1,2- and 1,1,2,2-tetrafluoropropane and 1,1,1,2,2- pentafluoropropane), and 2-fluoro,2-methylpropane. Standard entropies and heat capacities are calculated using the rigid-rotor-harmonic-oscillator approximation with direct integration over energy levels of the intramolecular rotation potential energy curve. Enthalpies of formation are estimated using G2MP2 total energies and isodesmic reactions. Thermodynamic properties for fluorinated carbon groups C/C/F/H2, C/C/F2/H, C/C/F3, C/C2/F/H, C/C2/F2 and C/C3/F for fluorinated alkane compounds, CD/F/H and CD/F2 for fluorinated alkene compounds and CT/F for fluorinated alkyne compounds are estimated. Fluorine-fluorine interaction terms F/F, 2F/F, 3F/F, 2F/2F, 3F/2F and 3F/3F for alkane compounds, F//F, 2F//F and 2F/2F for alkene compounds, and F///F for alkyne compound are also estimated.

Argon/UF6 plasma exhaust gas reconstitution experiments using preheated fluorine and on-line diagnostics. [fissioning uranium plasma core reactor design

NASA Technical Reports Server (NTRS)

Roman, W. C.

1979-01-01

The feasibility of employing a flowing, high-temperature, pure fluorine/UF6 regeneration system to efficiently convert a large fraction of the effluent plasma exhaust back to pure UF6 was demonstrated. The custom built T.O.F. mass spectrometer sampling system permitted on-line measurements of the UF6 concentration at different locations in the exhaust system. Negligible amounts ( 100 ppm) of UF6 were detected in the axial bypass exhaust duct and the exhaust ducts downstream of the cryogenic trap system used to collect the UF6, thus verifying the overall system efficiency over a range of operating conditions. Use of a porous Monel duct as part of the exhaust duct system, including provision for injection of pure fluorine, provided a viable technique to eliminate uranium compound residue on the inside surface of the exhaust ducts. Typical uranium compound mass deposition per unit area of duct was 2 micron g/sq cm. This porous duct technique is directly applicable to future uranium compound transfer exhaust systems. Throughout these experiments, additional basic data on the corrosion aspects of hot, pressurized UF6/fluorine were also accumulated.

Current and historical concentrations of poly and perfluorinated compounds in sediments of the northern Great Lakes - Superior, Huron, and Michigan.

PubMed

Codling, Garry; Hosseini, Soheil; Corcoran, Margaret B; Bonina, Solidea; Lin, Tian; Li, An; Sturchio, Neil C; Rockne, Karl J; Ji, Kyunghee; Peng, Hui; Giesy, John P

2018-05-01

Current and historical concentrations of 22 poly- and perfluorinated compounds (PFASs) in sediment collected from Lake Superior and northern Lake Michigan in 2011 and Lake Huron in 2012 are reported. The sampling was performed in two ways, Ponar grabs of surface sediments for current spatial distribution across the lake and dated cores for multi-decadal temporal trends. Mean concentrations of the sum of PFASs (∑PFASs) were 1.5, 4.6 and 3.1 ng g -1 dry mas (dm) in surface sediments for Lakes Superior, Michigan and Huron, respectively. Of the five Laurentian Lakes, the watersheds of Superior and Huron are the less densely populated by humans, and concentrations observed were typically less and from more diffuse sources, due to lesser urbanization and industrialization. However, some regions of greater concentrations were observed and might indicate more local, point sources. In core samples concentrations ranged from 7 that include perfluoro-n-octane sulfonate (PFOS) bind more strongly to sediment, which resulted in more accurate analyses of temporal trends. Shorter-chain PFASs, such as perfluoro-n-butanoic acid which is the primary replacement for C8 PFASs that have been phased out, are more soluble and were identified in some core layers at depths corresponding to pre-production periods. Thus, analyses of temporal trends of these more soluble compounds in cores of sediments were less accurate. Total elemental fluorine (TF) and extractable organic fluorine (EOF) indicated that identified PFASs were not a significant fraction of fluorine containing compounds in sediment (<0.01% in EOF). Copyright © 2018 Elsevier Ltd. All rights reserved.

Compilation of Requirements for Safe Handling of Fluorine and Fluorine-Containing Products of Uranium Hexafluoride Conversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferrada, J.J.

2000-04-03

Public Law (PL) 105-204 requires the U.S. Department of Energy to develop a plan for inclusion in the fiscal year 2000 budget for conversion of the Department's stockpile of depleted uranium hexafluoride (DUF{sub 6}) to a more stable form over an extended period. The conversion process into a more stable form will produce fluorine compounds (e.g., elemental fluorine or hydrofluoric acid) that need to be handled safely. This document compiles the requirements necessary to handle these materials within health and safety standards, which may apply in order to ensure protection of the environment and the safety and health of workersmore » and the public. Fluorine is a pale-yellow gas with a pungent, irritating odor. It is the most reactive nonmetal and will react vigorously with most oxidizable substances at room temperature, frequently with ignition. Fluorine is a severe irritant of the eyes, mucous membranes, skin, and lungs. In humans, the inhalation of high concentrations causes laryngeal spasm and broncospasms, followed by the delayed onset of pulmonary edema. At sublethal levels, severe local irritation and laryngeal spasm will preclude voluntary exposure to high concentrations, unless the individual is trapped or incapacitated. A blast of fluorine gas on the shaved skin of a rabbit causes a second degree burn. Lower concentrations cause severe burns of insidious onset, resulting in ulceration, similar to the effects produced by hydrogen fluoride. Hydrofluoric acid is a colorless, fuming liquid or gas with a pungent odor. It is soluble in water with release of heat. Ingestion of an estimated 1.5 grams produced sudden death without gross pathological damage. Repeated ingestion of small amounts resulted in moderately advanced hardening of the bones. Contact of skin with anhydrous liquid produces severe burns. Inhalation of AHA or aqueous hydrofluoric acid mist or vapors can cause severe respiratory tract irritation that may be fatal. Based on the extreme chemical properties of these chemicals as noted above, fluorine or fluorine compounds must be handled appropriately within the boundaries of many safety requirements for the protection of the environment and the public. This report analyzes the safety requirements that regulatory agencies have issued to handle fluorine or fluorine compounds and lists them in Table 1. Table 1 lists the source of the requirements, the specific section of the source document, and a brief description of the requirements.« less

Preparation of highly fluorinated diols containing ether linkages.

NASA Technical Reports Server (NTRS)

Rochow, S. E.; Stump, E. C., Jr.

1970-01-01

Hydroxy-terminated perfluoroethers and polyurethane resins derived from ethers have outstanding chemical resistance and good thermal properties. They can be used as potting compounds, coatings, and seals. The hydroxy-terminated ethers serve as intermediates in the synthesis of highly fluorinated elastomers and adhesives.

Quantitative Assessment of the Impact of Fluorine Substitution on P-Glycoprotein (P-gp) Mediated Efflux, Permeability, Lipophilicity, and Metabolic Stability.

PubMed

Pettersson, Martin; Hou, Xinjun; Kuhn, Max; Wager, Travis T; Kauffman, Gregory W; Verhoest, Patrick R

2016-06-09

Strategic replacement of one or more hydrogen atoms with fluorine atom(s) is a common tactic to improve potency at a given target and/or to modulate parameters such as metabolic stability and pKa. Molecular weight (MW) is a key parameter in design, and incorporation of fluorine is associated with a disproportionate increase in MW considering the van der Waals radius of fluorine versus hydrogen. Herein we examine a large compound data set to understand the effect of introducing fluorine on the risk of encountering P-glycoprotein mediated efflux (as measured by MDR efflux ratio), passive permeability, lipophilicity, and metabolic stability. Statistical modeling of the MDR ER data demonstrated that an increase in MW as a result of introducing fluorine atoms does not lead to higher risk of P-gp mediated efflux. Fluorine-corrected molecular weight (MWFC), where the molecular weight of fluorine has been subtracted, was found to be a more relevant descriptor.

Synthesis of Perfluorinated Ethers by Solution Phase Direct Fluorination: An Adaptation of the La-Mar Technique

DTIC Science & Technology

1990-08-22

Six of the 3 perfluorinated ethers prepared have been previously synthesized by other methods: perfluoro -5,5-bis(ethoxy- f methyl) -3,7-dioxanonane...from partially fluorinated starting material [34]. Third, as with perfluoroalkanes and simple perfluoroethers , Clark’s experimental results indicated 3...a highly branched perfluoroether ) by direct fluorination 3 in solution. Second, since some of these perfluorinated compounds had been previously

Charge-specific size-dependent separation of water-soluble organic molecules by fluorinated nanoporous networks

NASA Astrophysics Data System (ADS)

Byun, Jeehye; Patel, Hasmukh A.; Thirion, Damien; Yavuz, Cafer T.

2016-11-01

Molecular architecture in nanoscale spaces can lead to selective chemical interactions and separation of species with similar sizes and functionality. Substrate specific sorbent chemistry is well known through highly crystalline ordered structures such as zeolites, metal organic frameworks and widely available nanoporous carbons. Size and charge-dependent separation of aqueous molecular contaminants, on the contrary, have not been adequately developed. Here we report a charge-specific size-dependent separation of water-soluble molecules through an ultra-microporous polymeric network that features fluorines as the predominant surface functional groups. Treatment of similarly sized organic molecules with and without charges shows that fluorine interacts with charges favourably. Control experiments using similarly constructed frameworks with or without fluorines verify the fluorine-cation interactions. Lack of a σ-hole for fluorine atoms is suggested to be responsible for this distinct property, and future applications of this discovery, such as desalination and mixed matrix membranes, may be expected to follow.

Charge-specific size-dependent separation of water-soluble organic molecules by fluorinated nanoporous networks

PubMed Central

Byun, Jeehye; Patel, Hasmukh A.; Thirion, Damien; Yavuz, Cafer T.

2016-01-01

Molecular architecture in nanoscale spaces can lead to selective chemical interactions and separation of species with similar sizes and functionality. Substrate specific sorbent chemistry is well known through highly crystalline ordered structures such as zeolites, metal organic frameworks and widely available nanoporous carbons. Size and charge-dependent separation of aqueous molecular contaminants, on the contrary, have not been adequately developed. Here we report a charge-specific size-dependent separation of water-soluble molecules through an ultra-microporous polymeric network that features fluorines as the predominant surface functional groups. Treatment of similarly sized organic molecules with and without charges shows that fluorine interacts with charges favourably. Control experiments using similarly constructed frameworks with or without fluorines verify the fluorine-cation interactions. Lack of a σ-hole for fluorine atoms is suggested to be responsible for this distinct property, and future applications of this discovery, such as desalination and mixed matrix membranes, may be expected to follow. PMID:27830697

Synthesis, metabolism and systemic transport of a fluorinated mimic of the endogenous jasmonate precursor OPC-8:0.

PubMed

Jimenez-Aleman, Guillermo H; Scholz, Sandra S; Heyer, Monika; Reichelt, Michael; Mithöfer, Axel; Boland, Wilhelm

2015-12-01

Jasmonates (JAs) are fatty acid derivatives that mediate many developmental processes and stress responses in plants. Synthetic jasmonate derivatives (commonly isotopically labeled), which mimic the action of the endogenous compounds are often employed as internal standards or probes to study metabolic processes. However, stable-isotope labeling of jasmonates does not allow the study of spatial and temporal distribution of these compounds in real time by positron emission tomography (PET). In this study, we explore whether a fluorinated jasmonate could mimic the action of the endogenous compound and therefore, be later employed as a tracer to study metabolic processes by PET. We describe the synthesis and the metabolism of (Z)-7-fluoro-8-(3-oxo-2-(pent-2-en-1-yl)cyclopentyl)octanoic acid (7F-OPC-8:0), a fluorinated analog of the JA precursor OPC-8:0. Like endogenous jasmonates, 7F-OPC-8:0 induces the transcription of marker jasmonate responsive genes (JRG) and the accumulation of jasmonates after its application to Arabidopsis thaliana plants. By using UHPLC-MS/MS, we could show that 7F-OPC-8:0 is metabolized in vivo similarly to the endogenous OPC-8:0. Furthermore, the fluorinated analog was successfully employed as a probe to show its translocation to undamaged systemic leaves when it was applied to wounded leaves. This result suggests that OPC-8:0 - and maybe other oxylipins - may contribute to the mobile signal which triggers systemic defense responses in plants. We highlight the potential of fluorinated oxylipins to study the mode of action of lipid-derived molecules in planta, either by conventional analytical methods or fluorine-based detection techniques. Copyright © 2015 Elsevier B.V. All rights reserved.

Novel Polyfluorinated Compounds Identified Using High ...

EPA Pesticide Factsheets

Concern over persistence, bioaccumulation, and toxicity has led to international regulation and phase-outs of certain perfluorinated compounds and little is known about their replacement products. High resolution mass spectrometry was used to investigate the occurrence and identity of replacement fluorinated compounds in surface water and sediment of the Tennessee River near Decatur, Alabama. Analysis of legacy Per- and polyfluoroalkyl substances (PFASs) revealed a marked increase in concentrations downstream of manufacturing facilities, with the most abundant compounds being perfluorooctanesulfonate (PFOS), perfluorobutanesulfonate (PFBS), and perfluorooctanoic acid (PFOA) as high as 220 ng L–1, 160 ng L–1, and 120 ng L–1, respectively. A series of nine polyfluorinated carboxylic acids was discovered, each differing by CF2CH2. These acids are likely products or byproducts of a manufacturing process that uses 1,1-difluoroethene, which is registered to a manufacturing facility in the area. Two other predominant compounds discovered have structures consistent with perfluorobutanesulfonate and perfluoroheptanoic acid but have a single hydrogen substituted for a fluorine someplace in their structure. A polyfluoroalkyl sulfate with differing mixes of hydrogen and fluorine substitution was also observed. N-methyl perfluorobutane sulfonamidoacetic acid (MeFBSAA) was observed at high concentrations and several other perfluorobutane sulfonamido substances were pres

Clean graphene electrodes on organic thin-film devices via orthogonal fluorinated chemistry.

PubMed

Beck, Jonathan H; Barton, Robert A; Cox, Marshall P; Alexandrou, Konstantinos; Petrone, Nicholas; Olivieri, Giorgia; Yang, Shyuan; Hone, James; Kymissis, Ioannis

2015-04-08

Graphene is a promising flexible, highly transparent, and elementally abundant electrode for organic electronics. Typical methods utilized to transfer large-area films of graphene synthesized by chemical vapor deposition on metal catalysts are not compatible with organic thin-films, limiting the integration of graphene into organic optoelectronic devices. This article describes a graphene transfer process onto chemically sensitive organic semiconductor thin-films. The process incorporates an elastomeric stamp with a fluorinated polymer release layer that can be removed, post-transfer, via a fluorinated solvent; neither fluorinated material adversely affects the organic semiconductor materials. We used Raman spectroscopy, atomic force microscopy, and scanning electron microscopy to show that chemical vapor deposition graphene can be successfully transferred without inducing defects in the graphene film. To demonstrate our transfer method's compatibility with organic semiconductors, we fabricate three classes of organic thin-film devices: graphene field effect transistors without additional cleaning processes, transparent organic light-emitting diodes, and transparent small-molecule organic photovoltaic devices. These experiments demonstrate the potential of hybrid graphene/organic devices in which graphene is deposited directly onto underlying organic thin-film structures.

Impact of Mono-Fluorination on the Photophysics of the Flavin Chromophore.

PubMed

Reiffers, Anna; Torres Ziegenbein, Christian; Engelhardt, Alyn; Kühnemuth, Ralf; Gilch, Peter; Czekelius, Constantin

2018-03-31

Three mono-fluorinated derivatives of the flavin core system 10-methyl-isoalloxazine (MIA) were synthesized. Aqueous solutions of these compounds were characterized by steady-state and time-resolved spectroscopy. The positions for the fluorination (6, 7 and 8) were motivated by the nodal structure of the frontier orbitals of MIA. In comparison with MIA, the fluorination results in bathochromic (6F- and 7F-MIA) and hypsochromic (8F-MIA) shifts of the adiabatic excitation energy of the lowest allowed transition. Shifts of up to ~500 cm -1 were observed. These spectroscopic shifts go along with changes in fluorescence quantum yields and lifetimes. In addition, triplet yields are affected. For 7F-MIA, a 50% increase in the fluorescence quantum yield as well as a 50% decrease in triplet yield is observed rendering the compound interesting for fluorescence applications. The measured effects are discussed in terms of qualitative perturbation theory. © 2018 The American Society of Photobiology.

Effect of soil contamination with fluorine on the yield and content of nitrogen forms in the biomass of crops.

PubMed

Szostek, Radosław; Ciećko, Zdzisław

2017-03-01

The research was based on a pot experiment, in which the response of eight species of crops to soil contamination with fluorine was investigated. In parallel, some inactivating substances were tested in terms of their potential use for the neutralization of the harmful influence of fluorine on plants. The response of crops to soil contamination with fluorine was assessed according to the volume of biomass produced by aerial organs and roots as well as their content of N-total, N-protein, and N-NO 3 - . The following crops were tested: maize, yellow lupine, winter oilseed rape, spring triticale, narrow-leaf lupine, black radish, phacelia, and lucerne. In most cases, soil pollution with fluorine stimulated the volume of biomass produced by the plants. The exceptions included grain and straw of spring triticale, maize roots, and aerial parts of lucerne, where the volume of harvested biomass was smaller in treatments with fluorine-polluted soil. Among the eight plant species, lucerne was most sensitive to the pollution despite smaller doses of fluorine in treatments with this plant. The other species were more tolerant to elevated concentrations of fluorine in soil. In most of the tested plants, the analyzed organs contained more total nitrogen, especially aerial organs and roots of black radish, grain and straw of spring triticale, and aerial biomass of lucerne. A decrease in the total nitrogen content due to soil contamination with fluorine was detected only in the aerial mass of yellow lupine. With respect to protein nitrogen, its increase in response to fluorine as a soil pollutant was found in grain of spring triticale and roots of black radish, whereas the aerial biomass of winter oilseed rape contained less of this nutrient. Among the analyzed neutralizing substances, lime most effectively alleviated the negative effect of soil pollution with fluorine. The second most effective substance was loam, while charcoal was the least effective in this respect. Our results showed the effect of soil contamination with fluorine on the yield and chemical composition of fluorine depended on the species and organ of a tested plant, on the rate of the xenobotic element and on the substance added to soil in order to neutralize fluorine.

Fluorine bearing sydnones with styryl ketone group: synthesis and their possible analgesic and anti-inflammatory activities.

PubMed

Deshpande, Shreenivas Ramachandrarao; Pai, Karkala Vasantakumar

2012-04-01

In continuation of structure activity relationship studies, a panel of fluorine containing sydnones with styryl ketone group 4-[1-oxo-3-(substituted aryl)-2-propenyl]-3-(3-chloro-4-fluorophenyl)sydnones 2a-i, was synthesized as better analgesic and anti-inflammatory agents. The title compounds were formed by condensing 4-acetyl-3-(3-chloro-4-fluorophenyl)sydnone with various substituted aryl aldehydes, characterized by spectral studies and evaluated at 100 mg\\kg b.w., p.o. for analgesic, anti-inflammatory and ulcerogenic activities. Compounds 2c and 2e showed good analgesic effect in acetic acid-induced writhing while none showed significant activity in hot plate assay in mice. In carrageenan-induced rat paw oedema test, compound 2c and 2f exhibited good anti-inflammatory effect at 3rd h, whereas compounds 2c, 2e, 2d, 2g and 2h showed activity in croton oil induced ear oedema assay in mice. Compounds 2c and 2e were less ulcerogenic than ibuprofen in rats, when tested by ulcer index method. Compounds with electron attracting substituents such as 2c and 2e were found to be promising in terms of the ratio of efficacy and adverse effect. These compounds generally exhibited better activity than those of earlier series signifying fluorine substitution.

Low Level Exposure to Sulfur Mustard: Development of a SOP for Analysis of Albumin Adducts and of a System for Non-Invasive Diagnosis on Skin

DTIC Science & Technology

2007-08-01

of fluorinated amino acid derivatives under Electron Capture Atmospheric Pressure Chemical Ionization (EC APCI) conditions results in far better...Figure 6). Mass spectrometric analyses indicated that at least for the synthetic reference compound, the fluorinated derivative could be determined... fluorinated amino acid derivatives under EC APCI conditions (vide supra) results in far better detection limits, when compared to normal electrospray MS

An Evaluation of Polymer Coatings for the Promotion of Dropwise Condensation of Steam.

DTIC Science & Technology

1984-03-01

thermosetting, modi- fied polyester insulating varnish . Although not expected to perfcrm as %ell as the fluorinated compounds, ease of appli- cation...xylylene which can he vapor deposited in very thin films. Unlike PTEE, parylene-N contains no fluorine and therefore would nct be expected to be as...perform. Knowing that water has a surface tensicz of approximately 71.9 dynes/cm and riferring tc Table I, it can be seen that the fluorinated polymers

Recent advances in fluorination techniques and their anticipated impact on drug metabolism and toxicity.

PubMed

Murphy, Cormac D; Sandford, Graham

2015-04-01

Fluorine's unique physicochemical properties make it a key element for incorporation into pharmacologically active compounds. Its presence in a drug can alter a number of characteristics that affect ADME-Tox, which has prompted efforts at improving synthetic fluorination procedures. This review describes the influence of fluorine on attributes such as potency, lipophilicity, metabolic stability and bioavailablility and how the effects observed are related to the physicochemical characteristics of the element. Examples of more recently used larger scale synthetic methods for introduction of fluorine into drug leads are detailed and the potential for using biological systems for fluorinated drug production is discussed. The synthetic procedures for carbon-fluorine bond formation largely still rely on decades-old technology for the manufacturing scale and new reagents and methods are required to meet the demands for the preparation of structurally more complex drugs. The improvement of in vitro and computational methods should make fluorinated drug design more efficient and place less emphasis on approaches such as fluorine scanning and animal studies. The introduction of new fluorinated drugs, and in particular those that have novel fluorinated functional groups, should be accompanied by rigorous environmental assessment to determine the nature of transformation products that may cause ecological damage.

Fluorine-free electrolytes for all-solid sodium-ion batteries based on percyano-substituted organic salts

PubMed Central

Bitner-Michalska, Anna; Nolis, Gene M.; Żukowska, Grażyna; Zalewska, Aldona; Poterała, Marcin; Trzeciak, Tomasz; Dranka, Maciej; Kalita, Michał; Jankowski, Piotr; Niedzicki, Leszek; Zachara, Janusz; Marcinek, Marek; Wieczorek, Władysław

2017-01-01

A new family of fluorine-free solid-polymer electrolytes, for use in sodium-ion battery applications, is presented. Three novel sodium salts withdiffuse negative charges: sodium pentacyanopropenide (NaPCPI), sodium 2,3,4,5-tetracyanopirolate (NaTCP) and sodium 2,4,5-tricyanoimidazolate (NaTIM) were designed andtested in a poly(ethylene oxide) (PEO) matrix as polymer electrolytes for anall-solid sodium-ion battery. Due to unique, non-covalent structural configurations of anions, improved ionic conductivities were observed. As an example, “liquid-like” high conductivities (>1 mS cm−1) were obtained above 70 °C for solid-polymer electrolyte with a PEO to NaTCP molar ratio of 16:1. All presented salts showed high thermal stability and suitable windows of electrochemical stability between 3 and 5 V. These new anions open a new class of compounds with non-covalent structure for electrolytes system applications. PMID:28067301

Fluorine-free electrolytes for all-solid sodium-ion batteries based on percyano-substituted organic salts

NASA Astrophysics Data System (ADS)

Bitner-Michalska, Anna; Nolis, Gene M.; Żukowska, Grażyna; Zalewska, Aldona; Poterała, Marcin; Trzeciak, Tomasz; Dranka, Maciej; Kalita, Michał; Jankowski, Piotr; Niedzicki, Leszek; Zachara, Janusz; Marcinek, Marek; Wieczorek, Władysław

2017-01-01

A new family of fluorine-free solid-polymer electrolytes, for use in sodium-ion battery applications, is presented. Three novel sodium salts withdiffuse negative charges: sodium pentacyanopropenide (NaPCPI), sodium 2,3,4,5-tetracyanopirolate (NaTCP) and sodium 2,4,5-tricyanoimidazolate (NaTIM) were designed andtested in a poly(ethylene oxide) (PEO) matrix as polymer electrolytes for anall-solid sodium-ion battery. Due to unique, non-covalent structural configurations of anions, improved ionic conductivities were observed. As an example, “liquid-like” high conductivities (>1 mS cm-1) were obtained above 70 °C for solid-polymer electrolyte with a PEO to NaTCP molar ratio of 16:1. All presented salts showed high thermal stability and suitable windows of electrochemical stability between 3 and 5 V. These new anions open a new class of compounds with non-covalent structure for electrolytes system applications.

The Determination of the Smoke Hazards Resulting from the Burning of Shipboard Materials Utilized by the US Navy.

DTIC Science & Technology

1981-08-31

Interior Paairt r’ts RorzotalSapleIeun Forle Tranduer Figure I. Combustion Products Test Chamber. .. 2. *Sold hda 0 Ol~n kb 3’. 8.iIdg IN= W I Vll ue2...hydrocarbons (alkanes, alkenes, and alkynes), alcohols, aldehydes, ketones, ethers, carboxylic acids , aromatic hydrocarbons, polycyclic aromatic hydrocarbons...carboxylic acids , a few nitriles, acetaldehyde, and acetone. A few exotic fluorine containing organic compounds have unusually low refractive indices for

Fluorination of thiocarbonyl compounds with Bis(2-methoxyethyl)aminosulfur trifluoride (Deoxo-fluor reagent): A facile synthesis of gem-difluorides

PubMed

Lal; Lobach; Evans

2000-08-11

A variety of thiocarbonyl derivatives (thioketone, thioester, thioamide, dithioester, and dithiocarbamate) were converted to the corresponding gem-difluorides in excellent yields on reaction with the fluorinating agent, bis(2-methoxyethyl)aminosulfur trifluoride, in the presence of SbCl(3).

Process for producing 8-fluoropurines

DOEpatents

Barrio, J.R.; Satyamurthy, N.; Namavari, M.; Phelps, M.E.

1999-01-19

An efficient, regio-controlled approach to the synthesis of 8-fluoropurines by direct fluorination of purines with dilute elemental fluorine, or acetyl hypofluorite, is provided. In a preferred embodiment, a purine compound is dissolved in a polar solvent and reacted with a dilute mixture of F{sub 2} in He or other inert gas.

Molecular Packing of Functionalized Fluorinated Lipids in Langmuir Monolayers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Landsberg, Michael J.; Ruggles, Jeremy L.; Hussein, Waleed M.

2012-01-20

Fluorinated amphipaths are a fascinating class of compounds, which, despite significant challenges associated with their syntheses, have found use across a number of areas of biotechnology. Applications range from the in vitro stabilization of membrane proteins to the development of enhanced stability intravenous drug and gene delivery systems. More recently, monolayer-forming fluorinated lipids have found use in the 2D crystallization of detergent-solubilized hydrophobic or partially hydrophobic proteins at the air-water interface. In this study, we investigate the surface properties of a novel suite of monolayer forming, partially fluorinated lipids. These modular lipid structures contain a densely fluorinated insertion in themore » hydrocarbon tail and a synthetically modifiable headgroup. Analyses of surface-pressure area isotherms and X-ray reflectometry profiles reveal that the lipids spread into fluid monolayers and are more compressible than their non-fluorinated counterparts. Furthermore, the data support a model whereby the partially fluorinated chains of the lipid tails form a film which is fundamentally incompatible with detergents and other destabilizing amphipaths.« less

Aldolase-catalysed stereoselective synthesis of fluorinated small molecules.

PubMed

Windle, Claire L; Berry, Alan; Nelson, Adam

2017-04-01

The introduction of fluorine has been widely exploited to tune the biological functions of small molecules. Indeed, around 20% of leading drugs contain at least one fluorine atom. Yet, despite profound effects of fluorination on conformation, there is only a limited toolkit of reactions that enable stereoselective synthesis of fluorinated compounds. Aldolases are useful catalysts for the stereoselective synthesis of bioactive small molecules; however, despite fluoropyruvate being a viable nucleophile for some aldolases, the potential of aldolases to control the formation of fluorine-bearing stereocentres has largely been untapped. Very recently, it has been shown that aldolase-catalysed stereoselective carboncarbon bond formation with fluoropyruvate as nucleophile enable the synthesis of many α-fluoro β-hydroxy carboxyl derivatives. Furthermore, an understanding of the structural basis for the stereocontrol observed in these reactions is beginning to emerge. Here, we review the application of aldolase catalysis in the stereocontrolled synthesis of chiral fluorinated small molecules, and highlight likely areas for future developments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Volcanogenic fluorine in rainwater around active degassing volcanoes: Mt. Etna and Stromboli Island, Italy.

PubMed

Bellomo, S; D'Alessandro, W; Longo, M

2003-01-01

Many studies have assessed the strong influence of volcanic activity on the surrounding environment. This is particularly true for strong gas emitters such as Mt. Etna and Stromboli volcanoes. Among volcanic gases, fluorine compounds are potentially very harmful. Fluorine cycling through rainwater in the above volcanic areas was studied analysing more than 400 monthly bulk samples. Data indicate that only approximately 1% of fluorine emission through the plume is deposited on the two volcanic areas by meteoric precipitations. Although measured bulk rainwater fluorine fluxes are comparable to and sometimes higher than in heavily polluted areas, their influence on the surrounding vegetation is limited. Only annual crops, in fact, show some damage that could be an effect of fluorine deposition, indicating that long-living endemic plant species or varieties have developed some kind of resistance. Copyright 2002 Elsevier Science B.V.

(Polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of enhanced utility, uses thereof, and products based thereon

DOEpatents

Marks, Tobin J.; Chen, You-Xian

2001-01-01

The (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are novel weakly coordinating anions which are are highly fluorinated. (Polyfluoroaryl)fluoroanions of one such type contain at least one ring substituent other than fluorine. These (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium have greater solubility in organic solvents, or have a coordinative ability essentially equal to or less than that of the corresponding (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium in which the substituent is replaced by fluorine. Another type of new (polyfluoroaryl)fluoroanion of aluminum, gallium, and indium have 1-3 perfluorinated fused ring groups and 2-0 perfluorophenyl groups. When used as a cocatalyst in the formation of novel catalytic complexes with d- or f-block metal compounds having at least one leaving group such as a methyl group, these anions, because of their weak coordination to the metal center, do not interefere in the ethylene polymerization process, while affecting the the propylene process favorably, if highly isotactic polypropylene is desired. Thus, the (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of this invention are useful in various polymerization processes such as are described.

Microsolvation of Fluoromethane.

PubMed

Rosenberg, Robert E

2016-09-29

Fluorinated organic compounds are ubiquitous in the pharmaceutical and agricultural industries. To better discern the mode of action of these compounds, it is critical to understand the potential for and strength of hydrogen bonds involving fluorine. It is known that CH3F forms a hydrogen bond with H2O in the gas phase but does not dissolve in bulk water. This paper examines CH3F surrounded by one to six water molecules. For systems of similar topologies, CH3F formed hydrogen bonds of nearly the same strength as water. Although CH3F can bind to a second water cluster with only a modest loss in binding energy, it must bind to these clusters as a double hydrogen bond acceptor. This means that CH3F cannot form a low-energy cyclic 2D hydrogen bonding network with water molecules, which limits its solubility in bulk water. However, CH3F should be able to bind to the periphery of small hydrogen bonding networks. These conclusions were not appreciably altered by SMD calculations. A more complete consideration of solvation, especially entropic effects, was not undertaken. Data for geometries, population changes, and vibrational frequency shifts were also analyzed and compared to binding energies.

Uniaxially oriented polycrystalline thin films and air-stable n-type transistors based on donor-acceptor semiconductor (diC8BTBT)(FnTCNQ) [n = 0, 2, 4

NASA Astrophysics Data System (ADS)

Shibata, Yosei; Tsutsumi, Jun'ya; Matsuoka, Satoshi; Matsubara, Koji; Yoshida, Yuji; Chikamatsu, Masayuki; Hasegawa, Tatsuo

2015-04-01

We report the fabrication of high quality thin films for semiconducting organic donor-acceptor charge-transfer (CT) compounds, (diC8BTBT)(FnTCNQ) (diC8BTBT = 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene and FnTCNQ [n = 0,2,4] = fluorinated derivatives of 7,7,8,8,-tetracyanoquinodimethane), which have a high degree of layered crystallinity. Single-phase and uniaxially oriented polycrystalline thin films of the compounds were obtained by co-evaporation of the component donor and acceptor molecules. Organic thin-film transistors (OTFTs) fabricated with the compound films exhibited n-type field-effect characteristics, showing a mobility of 6.9 × 10-2 cm2/V s, an on/off ratio of 106, a sub-threshold swing of 0.8 V/dec, and an excellent stability in air. We discuss the suitability of strong intermolecular donor-acceptor interaction and the narrow CT gap nature in compounds for stable n-type OTFT operation.

Catalysis for Fluorination and Trifluoromethylation

PubMed Central

Furuya, Takeru; Kamlet, Adam S.; Ritter, Tobias

2011-01-01

Preface Recent advances in catalysis have made the incorporation of fluorine into complex organic molecules easier than ever before, but selective, general, and practical fluorination reactions remain sought after. Fluorination of molecules often imparts desirable properties such as metabolic and thermal stability, and fluorinated molecules are therefore frequently used as pharmaceuticals or materials. Even with the latest advances in chemistry, carbon–fluorine bond formation in complex molecules is still a significant challenge. Within the last few years, new reactions to make organofluorides have emerged and exemplify how to overcome some of the intricate challenges associated with fluorination. PMID:21614074

Modern Approaches for Asymmetric Construction of Carbon-Fluorine Quaternary Stereogenic Centers: Synthetic Challenges and Pharmaceutical Needs.

PubMed

Zhu, Yi; Han, Jianlin; Wang, Jiandong; Shibata, Norio; Sodeoka, Mikiko; Soloshonok, Vadim A; Coelho, Jaime A S; Toste, F Dean

2018-04-11

New methods for preparation of tailor-made fluorine-containing compounds are in extremely high demand in nearly every sector of chemical industry. The asymmetric construction of quaternary C-F stereogenic centers is the most synthetically challenging and, consequently, the least developed area of research. As a reflection of this apparent methodological deficit, pharmaceutical drugs featuring C-F stereogenic centers constitute less than 1% of all fluorine-containing medicines currently on the market or in clinical development. Here we provide a comprehensive review of current research activity in this area, including such general directions as asymmetric electrophilic fluorination via organocatalytic and transition-metal catalyzed reactions, asymmetric elaboration of fluorine-containing substrates via alkylations, Mannich, Michael, and aldol additions, cross-coupling reactions, and biocatalytic approaches.

Mesoporous Fluorinated Metal-Organic Frameworks with Exceptional Adsorption of Fluorocarbons and CFCs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Teng-Hao; Popov, Ilya; Kaveevivitchai, Watchareeya

2016-02-08

Two mesoporous fluorinated metal–organic frameworks (MOFs) were synthesized from extensively fluorinated tritopic carboxylate- and tetrazolate-based ligands. The tetrazolate-based framework MOFF-5 has an accessible surface area of 2445 m 2g -1, the highest among fluorinated MOFs. Crystals of MOFF-5 adsorb hydrocarbons, fluorocarbons, and chlorofluorocarbons (CFCs)—the latter two being ozone-depleting substances and potent greenhouse species—with weight capacities of up to 225%. The material exhibits an apparent preference for the adsorption of non-spherical molecules, binding unusually low amounts of both tetrafluoromethane and sulfur hexafluoride.

Transition Metal-Mediated and -Catalyzed C-F Bond Activation via Fluorine Elimination.

PubMed

Fujita, Takeshi; Fuchibe, Kohei; Ichikawa, Junji

2018-06-28

Activation of carbon-fluorine (C-F) bonds is an important topic in synthetic organic chemistry recently. Among the methods for C-F bond cleavage, metal mediated and catalyzed β- or α-fluorine elimination proceeds under mild conditions compared with oxidative addition of C-F bond. The β- or α-fluorine elimination is initiated from organometallic intermediates having fluorine substituents on carbon atoms β or α to metal centers, respectively. Transformations via these elimination processes (C-F bond cleavage), which are typically preceded by carbon-carbon (or carbon-heteroatom) bond formation, have been remarkably developed as C-F bond activation methods in the past five years. In this minireview, we summarize the applications of transition metal-mediated and -catalyzed fluorine elimination to synthetic organic chemistry from a historical perspective for early studies and from a systematic perspective for recent studies. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and biological evaluation of novel 5-aryl-4-(5-nitrofuran-2-yl)-pyrimidines as potential anti-bacterial agents.

PubMed

Verbitskiy, Egor V; Baskakova, Svetlana A; Gerasimova, Natal'ya A; Evstigneeva, Natal'ya P; Zil'berberg, Natal'ya V; Kungurov, Nikolay V; Kravchenko, Marionella A; Skornyakov, Sergey N; Pervova, Marina G; Rusinov, Gennady L; Chupakhin, Oleg N; Charushin, Valery N

2017-07-01

A facile two-step synthetic approach to fluorinated and non-fluorinated 5-aryl-4-(5-nitrofuran-2-yl)-pyrimidines from readily available 5-bromo-4-(furan-2-yl)pyrimidine has been developed. All synthesized compounds were screened in vitro for their antibacterial activities against twelve various bacterial strains. It is demonstrated that some of these compounds exhibited significant antibacterial activities against strains Neisseria gonorrhoeae and Staphylococcus aureus, comparable and even higher with that commercial drug Spectinomycin. Copyright © 2017 Elsevier Ltd. All rights reserved.

EMISSIONS OF FLUORINATED COMPOUNDS FROM THE ...

EPA Pesticide Factsheets

Symposium Paper One of the emerging waste streams that will likely be disposed of in combustors is carpet, due to its high heating value and combustibility. Some of the stain-resistant coatings that carpeting is treated with contain perfluorinated compounds (PFCs) such as perfluorooctanoic acid (PFOA) and their corresponding homologues (C6 – C14 acids) as well as fluorotelomer alcohols and fluoropolymers. PFOA has recently been implicated as a chemical of concern due to its toxicity. It is unknown as to whether PFCs can be released from combustion, or formed as by-products in combustors. This paper reports on a study in a 0.73 kW pilot-scale rotary kiln incinerator simulator to qualitatively and, where applicable; quantitatively assess the potential for emissions of fluorinated compounds from combustion devices. In this study, a limited number of PFCs were found in trace levels in the stack, and the concentrations were relatively independent of kiln feed, suggesting that PFCs are effectively destroyed even under mild combustion conditions, and the trace levels that were found were due to either trace contamination of the sampling duct with fluorinated compounds due to historical use of Teflon and other fluorpolymers, or sampling artifacts.

Direct fluorination of phenolsulfonphthalein: a method for synthesis of positron-emitting indicators for in vivo pH measurement

PubMed Central

Kachur, Alexander V.; Popov, Anatoliy V.; Karp, Joel S.; Delikatny, E. James

2014-01-01

We report a reaction of direct electrophilic fluorination of phenolsulfonphthalein at mild conditions. This reaction affords the synthesis of novel positron-emitting 18F-labeled pH indicators. These compounds are useful for non-invasive in vivo pH measurement in biological objects. PMID:22790882

Microwave assisted synthesis and anti-lipase activity of some new fluorine-containing benzimidazoles.

PubMed

Menteşe, E; Yilmaz, F; Ülker, S; Kahveci, B

2015-01-01

In this study, a new series of fluorine containing benzimidazoles (4a-l) and bisbenzimidazoles (6a-c, 8) were synthesized by the reaction of o-phenylenediamines with iminoester hydrochlorides (3a-l, 7) in methanol under microwave irradiation. The structures of these newly synthesized compounds were identified by IR, (1)H-NMR, (13)C-NMR, mass spectroscopy and elemental analysis data. The synthesized compounds were screened for their pancreatic lipase activities. Our results indicate that the compounds 6a, 6b and 6c can serve as an anti-lipase agent. The compounds 6b and 6c inhibited pancreatic lipase activity by 84.03% and 97.49% at a concentration of 3 µg/mL, respectively. © Georg Thieme Verlag KG Stuttgart · New York.

Determination of adsorbable organic fluorine from aqueous environmental samples by adsorption to polystyrene-divinylbenzene based activated carbon and combustion ion chromatography.

PubMed

Wagner, Andrea; Raue, Brigitte; Brauch, Heinz-Jürgen; Worch, Eckhard; Lange, Frank T

2013-06-21

A new method for the determination of trace levels of adsorbable organic fluorine (AOF) in water is presented. Even if the individual contributing target compounds are widely unknown, this surrogate parameter is suited to identify typical organofluorine contaminations, such as with polyfluorinated chemicals (PFCs), and represents a lower boundary of the organofluorine concentration in water bodies. It consists of the adsorption of organofluorine chemicals on a commercially available synthetic polystyrene-divinylbenzene based activated carbon (AC) followed by analysis of the loaded AC by hydropyrolysis combustion ion chromatography (CIC). Inorganic fluorine is displaced by excess nitrate during the extraction step and by washing the loaded activated carbon with an acidic sodium nitrate solution. Due to its high purity the synthetic AC had a very low and reproducible fluorine blank (0.3 μg/g) compared to natural ACs (up to approximately 9 μg/g). Using this AC, fluoride and the internal standard phosphate could be detected free of chromatographic interferences. With a sample volume of 100 mL and 2× 100 mg of AC packed into two extraction columns combined in series, a limit of quantification (LOQ), derived according to the German standard method DIN 32645, of 0.3 μg/L was achieved. The recoveries of six model PFCs were determined from tap water and a municipal wastewater treatment plant (WWTP) effluent. Except for the extremely polar perfluoroacetic acid (recovery of approximately 10%) the model substances showed fairly good (50% for perfluorobutanoic acid (PFBA)) to very good fluorine recoveries (100±20% for perfluorooctanoic acid (PFOA), perfluorobutanesulfonate (PFBS), 6:2 fluorotelomersulfonate (6:2 FTS)), both from tap water and wastewater matrix. This new analytical protocol was exemplarily applied to several surface water and groundwater samples. The obtained AOF values were compared to the fluorine content of 19 target PFCs analyzed by high performance liquid chromatography-electrospray tandem mass spectrometry (HPLC-(-)ESI-MS/MS). In groundwater contaminated by PFC-containing aqueous film-forming foams (AFFFs) up to 50% of the AOF could be attributed to PFC target chemicals, while in diffuse contaminated samples only <5% of the AOF could be identified by PFC analysis. Copyright © 2013 Elsevier B.V. All rights reserved.

Flow-injection determination of total organic fluorine with off-line defluorination reaction on a solid sorbent bed.

PubMed

Musijowski, Jacek; Trojanowicz, Marek; Szostek, Bogdan; da Costa Lima, José Luis Fontes; Lapa, Rui; Yamashita, Hiroki; Takayanagi, Toshio; Motomizu, Shoji

2007-09-26

Considering recent reports on widespread occurrence and concerns about perfluoroalkyl substances (PFAS) in environmental and biological systems, analysis of these compounds have gained much attention in recent years. Majority of analyte-specific methods are based on a LC/MS/MS or a GC/MS detection, however many environmental or biological studies would benefit from a total organic fluorine (TOF) determination. Presented work was aimed at developing a method for TOF determination. TOF is determined as an amount of inorganic fluoride obtained after defluorination reaction conducted off-line using sodium biphenyl reagent directly on the sorbent without elution of retained analytes. Recovered fluoride was analyzed using flow-injection system with either fluorimetric or potentiometric detection. The TOF method was tested using perfluorocarboxylic acids (PFCA), including perfluorooctanoic acid (PFOA), as model compounds. Considering low concentrations of PFAS in natural samples, solid-phase extraction as a preconcentration procedure was evaluated. Several carbon-based sorbents were tested, namely multi-wall carbon nanotubes, carbon nanofibres and activated carbon. Good sorption of all analytes was achieved and defluorination reaction was possible to carry out directly on a sorbent bed. Recoveries obtained for PFCAs, adsorbed on an activated carbon sorbent, and measured as TOF, were 99.5+/-1.7, 110+/-9.4, 95+/-26, 120+/-32, 110+/-12 for C4, C6, C8, C10 and C12-PFCA, respectively. Two flow systems that would enable the defluorination reaction and fluoride determination in a single system were designed and tested.

Development of an 19F NMR method for the analysis of fluorinated acids in environmental water samples.

PubMed

Ellis, D A; Martin, J W; Muir, D C; Mabury, S A

2000-02-15

This investigation was carried out to evaluate 19F NMR as an analytical tool for the measurement of trifluoroacetic acid (TFA) and other fluorinated acids in the aquatic environment. A method based upon strong anionic exchange (SAX) chromatography was also optimized for the concentration of the fluoro acids prior to NMR analysis. Extraction of the analyte from the SAX column was carried out directly in the NMR solvent in the presence of the strong organic base, DBU. The method allowed the analysis of the acid without any prior cleanup steps being involved. Optimal NMR sensitivity based upon T1 relaxation times was investigated for seven fluorinated compounds in four different NMR solvents. The use of the relaxation agent chromium acetylacetonate, Cr(acac)3, within these solvent systems was also evaluated. Results show that the optimal NMR solvent differs for each fluorinated analyte. Cr(acac)3 was shown to have pronounced effects on the limits of detection of the analyte. Generally, the optimal sensitivity condition appears to be methanol-d4/2M DBU in the presence of 4 mg/mL of Cr-(acac)3. The method was validated through spike and recovery for five fluoro acids from environmentally relevant waters. Results are presented for the analysis of TFA in Toronto rainwater, which ranged from < 16 to 850 ng/L. The NMR results were confirmed by GC-MS selected-ion monitoring of the fluoroanalide derivative.

Design strategies to minimize the radiative efficiency of global warming molecules

PubMed Central

Bera, Partha P.; Francisco, Joseph S.; Lee, Timothy J.

2010-01-01

A strategy is devised to screen molecules based on their radiative efficiency. The methodology should be useful as one additional constraint when determining the best molecule to use for an industrial application. The strategy is based on the results of a recent study where we examined molecular properties of global warming molecules using ab initio electronic structure methods to determine which fundamental molecular properties are important in assessing the radiative efficiency of a molecule. Six classes of perfluorinated compounds are investigated. For similar numbers of fluorine atoms, their absorption of radiation in the IR window decreases according to perfluoroethers > perfluorothioethers ≈ sulfur/carbon compounds > perfluorocarbons > perfluoroolefins > carbon/nitrogen compounds. Perfluoroethers and hydrofluorethers are shown to possess a large absorption in the IR window due to (i) the C─O bonds are very polar, (ii) the C-O stretches fall within the IR window and have large IR intensity due to their polarity, and (iii) the IR intensity for C-F stretches in which the fluorine atom is bonded to the carbon that is bonded to the oxygen atom is enhanced due to a larger C─F bond polarity. Lengthening the carbon chain leads to a larger overall absorption in the IR window, though the IR intensity per bond is smaller. Finally, for a class of partially fluorinated compounds with a set number of electronegative atoms, the overall absorption in the IR window can vary significantly, as much as a factor of 2, depending on how the fluorine atoms are distributed within the molecule. PMID:20439762

Experimental design for a basic mixture on a fluorinated packing. The effect of composition of the mobile phase.

PubMed

Wang, Y; Harrison, M; Clark, B J

2006-02-10

An optimization methodology is introduced for investigating the separation and the retention behavior of analytes on a new fluorinated reversed-phase packing. Ten basic compounds were selected as test probes to study the predictive models developed by using SPSS and MATLAB software. A two-level orthogonal array design (OAD) was used to extract significant parameters. The significant factors were optimised using a central composite design to obtain the quadratic relationship between the dependent and the independent variables. Using this strategy, response surfaces were derived as the 3D and contour plots, and mathematical models were defined for the separation. The models had a satisfactory coefficient (R(2) > 0.97, n = 16). For the test compounds, the best separation condition was: MeCN/30 mM phosphate buffer pH 7.1(55.5:44.5, v/v) and 10 basic solutes were resolved in 22 min. The significant influence of the concentration of buffer shows that different mechanisms of separation for basic compounds on the fluorinated packing exist compared with a common ODS stationary phase.

Fluorinated diglucose detergents for membrane-protein extraction.

PubMed

Boussambe, Gildas Nyame Mendendy; Guillet, Pierre; Mahler, Florian; Marconnet, Anaïs; Vargas, Carolyn; Cornut, Damien; Soulié, Marine; Ebel, Christine; Le Roy, Aline; Jawhari, Anass; Bonneté, Françoise; Keller, Sandro; Durand, Grégory

2018-05-29

Fluorinated surfactants have scarcely been explored for the direct extraction of proteins from membranes because fluorination is believed to abrogate detergency. However, we have recently shown that a commercially available fluorinated surfactant readily solubilizes lipid membranes, thereby suggesting that fluorination per se does not interfere with detergent activity. In this work, we developed new fluorinated surfactants that exhibit detergency in terms of both lipid-vesicle solubilization and membrane-protein extraction. The compounds made and tested contain two glucose moieties as polar headgroup, a hydrogenated thioether linker, and a perfluorinated alkyl tail with either 4, 6, or 8 carbon atoms. The physicochemical properties of the micelles formed by the three fluorinated surfactants were evaluated by NMR spectroscopy, surface tensiometry, isothermal titration calorimetry, dynamic light scattering, small-angle X-ray scattering, and analytical ultracentrifugation. At 25°C, micellization was mainly entropy-driven, and the CMC values were found to decrease with chain length of the fluorinated tail, whereas the aggregation number increased with chain length. Remarkably, all three surfactants were found to solubilize lipid vesicles and extract a broad range of proteins from Escherichiacoli membranes. These findings demonstrate, for the first time, that nonionic fluorinated surfactants could be further exploited for the direct extraction and solubilization of membrane proteins. Copyright © 2018. Published by Elsevier Inc.

Fluorination of Boron-Doped Diamond Film Electrodes for Minimization of Perchlorate Formation.

PubMed

Gayen, Pralay; Chaplin, Brian P

2017-08-23

This research investigated the effects of surface fluorination on both rates of organic compound oxidation (phenol and terephthalic acid (TA)) and ClO 4 - formation at boron-doped diamond (BDD) film anodes at 22 °C. Different fluorination methods (i.e., electrochemical oxidation with perfluorooctanoic acid (PFOA), radio frequency plasma, and silanization) were used to incorporate fluorinated moieties on the BDD surface, which was confirmed by X-ray photoelectron spectroscopy (XPS). The silanization method was found to be the most effective fluorination method using a 1H,1H,2H,2H-perfluorodecyltrichlorosilane precursor to form a self-assembled monolayer (SAM) on the oxygenated BDD surface. The ClO 4 - formation decreased from rates of 0.45 ± 0.03 mmol m -2 min -1 during 1 mM NaClO 3 oxidation and 0.28 ± 0.01 mmol m -2 min -1 during 10 mM NaCl oxidation on the BDD electrode to below detectable levels (<0.12 μmoles m -2 min -1 ) for the BDD electrode functionalized by a 1H,1H,2H,2H-perfluorodecyltrichlorosilane SAM. These decreases in rates corresponded to 99.94 and 99.85% decreases in selectivity for ClO 4 - formation during the electrolysis of 10 mM NaCl and 1 mM NaClO 3 electrolytes, respectively. By contrast, the oxidation rates of phenol were reduced by only 16.3% in the NaCl electrolyte and 61% in a nonreactive 0.1 M KH 2 PO 4 electrolyte. Cyclic voltammetry with Fe(CN) 6 3-/4- and Fe 3+/2+ redox couples indicated that the long fluorinated chains created a blocking layer on the BDD surface that inhibited charge transfer via steric hindrance and hydrophobic effects. The surface coverages and thicknesses of the fluorinated films controlled the charge transfer rates, which was confirmed by estimates of film thicknesses using XPS and density functional theory simulations. The aliphatic silanized electrode also showed very high stability during OH • production. Perchlorate formation rates were below the detection limit (<0.12 μmoles m -2 min -1 ) for up to 10 consecutive NaClO 3 oxidation experiments.

Oxidative aliphatic C-H fluorination with manganese catalysts and fluoride ion

PubMed Central

Liu, Wei; Huang, Xiongyi; Groves, John T

2014-01-01

Fluorination is a reaction that is useful in improving the chemical stability and changing the binding affinity of biologically active compounds. The protocol described here can be used to replace aliphatic, C(sp3)-H hydrogen in small molecules with fluorine. Notably, isolated methylene groups and unactivated benzylic sites are accessible. The method uses readily available manganese porphyrin and manganese salen catalysts and various fluoride ion reagents, including silver fluoride (AgF), tetrabutylammonium fluoride and triethylamine trihydrofluoride (TREAT·HF), as the source of fluorine. Typically, the reactions afford 50–70% yield of mono-fluorinated products in one step. Two representative examples, the fragrance component celestolide and the nonsteroidal anti-inflammatory drug ibuprofen, are described; they produced useful isolated quantities (250–300 mg, ~50% yield) of fluorinated material over periods of 1–8 h. The procedures are performed in a typical fume hood using ordinary laboratory glassware. No special precautions to rigorously exclude water are required. PMID:24177292

Flame resistant elastomeric polymer development. [for use in space shuttle instrument packaging

NASA Technical Reports Server (NTRS)

Howarth, J. T.; Sheth, S. G.; Sidman, K. R.

1975-01-01

Elastomeric products were developed for use in the space shuttle program, and investigations were conducted to improve the properties of elastomers developed in previous programs, and to evaluate the possibility of using lower-cost general purpose polymers. Products were fabricated and processed on conventional processing equipment; these products include: foams based on fluorinated rubber flame-retarded compounds with a density of 20-30 pounds/cubic foot for use as padding and in helmets; foams based on urethane for use in instrument packaging in the space shuttle; flexible and semi-rigid films of fluorinated rubber and neoprene compounds that would not burn in a 70% nitrogen, 30% oxygen atmosphere, and in a 30% nitrogen, 70% oxygen atmosphere, respectively for use in packaging or in laminates; coated fabrics which used both nylon and Kelvar fabric substrates, coated with either fluorinated or neoprene polymer compositions to meet specific levels of flame retardancy; and other flame-resistant materials.

Synthesis and biological activity of the novel indanedione anticoagulant rodenticides containing fluorine

PubMed Central

Chen, Feng; Liu, Liping; Bai, Zengguo; Zhang, Tianhua; Zhao, Keke

2017-01-01

ABSTRACT Here, 3 fluorinated intermediates of drug were synthesized: (M1), (M2), (M3). Three new anticoagulant rodenticides were designed which were based on 4-hydroxycoumarin or 1,3-indandione, added acute toxicity groups containing fluorine. The structures of synthesized compounds were analyzed and proved by FT-IR spectroscopy and 1H nuclear magnetic resonance (1H-NMR). The compounds were also evaluated for their anticoagulant and acute biologic activity. In addition, both the acute orally toxicity and the feeding indexes of R1 and R2 were tested. The result of the experiment proved that the new synthesis of 1, 3 - indan diketone for maternal new anticoagulant rodenticide can replace the current 4 - hydroxyl coumarin as the mother of the second generation anticoagulant rodenticide and 1, 3 - indan diketone for maternal new anticoagulant rodenticides will have a good development prospect. PMID:27759485

Synthesis and biological activity of the novel indanedione anticoagulant rodenticides containing fluorine.

PubMed

Chen, Feng; Liu, Liping; Bai, Zengguo; Zhang, Tianhua; Zhao, Keke

2017-01-02

Here, 3 fluorinated intermediates of drug were synthesized: (M1), (M2), (M3). Three new anticoagulant rodenticides were designed which were based on 4-hydroxycoumarin or 1,3-indandione, added acute toxicity groups containing fluorine. The structures of synthesized compounds were analyzed and proved by FT-IR spectroscopy and 1 H nuclear magnetic resonance ( 1 H-NMR). The compounds were also evaluated for their anticoagulant and acute biologic activity. In addition, both the acute orally toxicity and the feeding indexes of R 1 and R 2 were tested. The result of the experiment proved that the new synthesis of 1, 3 - indan diketone for maternal new anticoagulant rodenticide can replace the current 4 - hydroxyl coumarin as the mother of the second generation anticoagulant rodenticide and 1, 3 - indan diketone for maternal new anticoagulant rodenticides will have a good development prospect.

[Clinical and pathogenetic aspects of the chronic occupational intoxication with fluorine compounds in modern reality].

PubMed

Roslaia, N A; Likhacheva, E I; Oranskiĭ, I E; Odinokaia, V A; Plotko, É G; Zhovtiak, E P; Fedorov, A A; Riabko, E V

2012-01-01

Multi-year follow-up of 358 workers of aluminum pot rooms, including 165 individuals suffering from fluorosis, has shown significant changes in the clinical picture of the chronic occupational fluorine intoxication, developed under modern conditions of production, at lower concentrations of fluorine compounds in the air of working area. In this connection, the pathology of the musculoskeletal system plays the dominating role in this clinical picture and has the large variability of combinations of the individual sections destructions of the bone tissue. The main criterion to establish the phase of the disease is still the number and severity of the signs of this destruction. The visceral pathology in contemporary production circumstances is registered with less frequency and loses a number of the previously described clinical manifestations, however, is still of some importance to identify the early signs of the disease and to prevent the dental fluorosis on time.

Mechanistic Insights into the Specificity of Human Cytosolic Sulfotransferase 2A1 (hSULT2A1) for Hydroxylated Polychlorinated Biphenyls Through the Use of Fluoro-tagged Probes

PubMed Central

Ekuase, E.J.; van ’t Erve, T.J.; Rahaman, A.; Robertson, L.W.; Duffel, M.W.; Luthe, G.

2015-01-01

Determining the relationships between the structures of substrates and inhibitors and their interactions with drug-metabolizing enzymes is of prime importance in predicting the toxic potential of new and legacy xenobiotics. Traditionally, quantitative structure activity relationship (QSAR) studies are performed with many distinct compounds. Based on the chemical properties of the tested compounds, complex relationships can be established so that models can be developed to predict toxicity of novel compounds. In this study, the use of fluorinated analogues as supplemental QSAR compounds was investigated. Substituting fluorine induces changes in electronic and steric properties of the substrate without substantially changing the chemical backbone of the substrate. In vitro assays were performed using purified human cytosolic sulfotransferase hSULT2A1 as a model enzyme. A mono-hydroxylated polychlorinated biphenyl (4-OH PCB 14) and its four possible mono-fluoro analogues were used as test compounds. Remarkable similarities were found between this approach and previously published QSAR studies for hSULT2A1. Both studies implicate the importance of dipole moment and dihedral angle as being important to PCB structure in respect to being substrates for hSULT2A1. We conclude that mono-fluorinated analogues of a target substrate can be a useful tool to study the structure activity relationships for enzyme specificity. PMID:26165989

Nitroimidazoles, Quinolones and Oxazolidinones as Fluorine Bearing Antitubercular Clinical Candidates.

PubMed

Patel, Rahul V; Keum, Young-Soo; Park, Se Won

2015-01-01

Tuberculosis is a leading killer of lives worldwide and the global curse of multi-drug resistant tuberculosis is attaining really dangerous levels. Synergistic interaction of HIV and TB is the twin epidemics in resource-limited countries as each potentiate progression of the other. The increasing emergence of MDR-TB and XDR-TB place an immense burden for the treatment of TB with currently available drugs. The situation urgently demands for the discovery of new drugs with novel mode of action and differs in structural features in order to overcome resistance appears in conventional TB therapeutics. The present report covers the discovery of three classes of antituberculosis drugs, Nitroimidazoles, Quinolones and Oxazolidinones, undergoing clinical development with fluorine atom in their structures. Highly electronegative fluorine atom plays a signature role in advancing medicinal innovations as it existence in the drug compounds critically influences metabolic stability and lipophilicity thereby delaying its elimination by the body which results into a long term in vivo efficiency of the drug. Presence of fluorine atom(s) in the drug structures described in this report, has been associated with the several fold increase in the overall potency of the compound as demonstrated since the early discoveries. 6 Fluorinated derivatives from these three classes as pretomanid, delamanid, moxifloxacin, gatifloxacin, linezolid and sutezolid have been discussed with their antituberculosis effects, mode of action, chemical synthetic routes and results of clinical studies.

Effect of sputtering power on MgF2 thin films deposited by sputtering technique under fluorine trapping

NASA Astrophysics Data System (ADS)

De, Rajnarayan; Haque, S. Maidul; Tripathi, S.; Prathap, C.; Rao, K. Divakar; Sahoo, N. K.

2016-05-01

A non-conventional magnetron sputtering technique was explored to deposit magnesium fluoride thin films using the concept of fluorine gas trapping without the introduction of additional fluorine gas flow inside the chamber. The effect of magnetron power from 50 W to 250 W has been explored on structural, optical and physical properties of the samples. Polycrystalline nature with tetragonal crystallinity of the films has been confirmed by GIXRD measurements along with thickness dependency. Monotonic increase of attenuation coefficient (k) with RF power has been explained in terms of target compound dissociation probability. In conclusion, with fluorine trapping method, the samples deposited at lower RF powers (<100 W) are found to be more suitable for optical applications.

19F DOSY NMR analysis for spin systems with nJFF couplings.

PubMed

Dal Poggetto, Guilherme; Favaro, Denize C; Nilsson, Mathias; Morris, Gareth A; Tormena, Cláudio F

2014-04-01

NMR is a powerful method for identification and quantification of drug components and contaminations. These problems present themselves as mixtures, and here, one of the most powerful tools is DOSY. DOSY works best when there is no spectral overlap between components, so drugs containing fluorine substituents are well-suited for DOSY analysis as (19)F spectra are typically very sparse. Here, we demonstrate the use of a modified (19)F DOSY experiment (on the basis of the Oneshot sequences) for various fluorinated benzenes. For compounds with significant (n) JFF coupling constants, as is common, the undesirable J-modulation can be efficiently suppressed using the Oneshot45 pulse sequence. This investigation highlights (19)F DOSY as a valuable and robust method for analysis of molecular systems containing fluorine atoms even where there are large fluorine-fluorine couplings. Copyright © 2014 John Wiley & Sons, Ltd.

Recent developments with boron as a platform for novel drug design.

PubMed

Leśnikowski, Zbigniew J

2016-06-01

After decades of development, the medicinal chemistry of compounds that contain a single boron atom has matured to the present status of having equal rights with other branches of drug discovery, although it remains a relative newcomer. In contrast, the medicinal chemistry of boron clusters is less advanced, but it is expanding and may soon become a productive area of drug discovery. The author reviews the current developments of medicinal chemistry of boron and its applications in drug design. First generation boron drugs that bear a single boron atom and second generation boron drugs that utilize boron clusters as pharmacophores or modulators of bioactive molecules are discussed. The advantages and gaps in our current understanding of boron medicinal chemistry, with a special focus on boron clusters, are highlighted. Boron is not a panacea for every drug discovery problem, but there is a good chance that it will become a useful addition to the medicinal chemistry tool box. The present status of boron resembles the medicinal chemistry status of fluorine three decades ago; indeed, currently, approximately 20% of pharmaceuticals on the market contain fluorine. The fact that novel boron compounds, especially those based on abiotic polyhedral boron hydrides, are currently unfamiliar could be advantageous because organisms may be less prone to developing resistance against boron cluster-based drugs.

Fluorination-enabled optimal morphology leads to over 11% efficiency for inverted small-molecule organic solar cells

PubMed Central

Deng, Dan; Zhang, Yajie; Zhang, Jianqi; Wang, Zaiyu; Zhu, Lingyun; Fang, Jin; Xia, Benzheng; Wang, Zhen; Lu, Kun; Ma, Wei; Wei, Zhixiang

2016-01-01

Solution-processable small molecules for organic solar cells have attracted intense attention for their advantages of definite molecular structures compared with their polymer counterparts. However, the device efficiencies based on small molecules are still lower than those of polymers, especially for inverted devices, the highest efficiency of which is <9%. Here we report three novel solution-processable small molecules, which contain π-bridges with gradient-decreased electron density and end acceptors substituted with various fluorine atoms (0F, 1F and 2F, respectively). Fluorination leads to an optimal active layer morphology, including an enhanced domain purity, the formation of hierarchical domain size and a directional vertical phase gradation. The optimal morphology balances charge separation and transfer, and facilitates charge collection. As a consequence, fluorinated molecules exhibit excellent inverted device performance, and an average power conversion efficiency of 11.08% is achieved for a two-fluorine atom substituted molecule. PMID:27991486

[Residue of organic fluorine pollutants in hair and nails collected from Tianjin].

PubMed

Yao, Dan; Zhang, Hong; Chai, Zhi-Fang; Shen, Jin-Can; Yang, Bo; Wang, Yan-Ping; Liu, Guo-Qing

2013-02-01

In order to explore the residue and distributions of organic fluorine pollutants in hair and nails, the residue levels of total fluorine (TF), extractable organic fluorine (EOF) and perfluorinated chemicals (PFCs) in hair and nails collected from Tianjin adults were measured by the cyclic neutron activation analysis (CNAA) combined with the high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The results showed that inorganic fluorine (mean: 2.0 mg.kg-1, 4.5 mg.kg-1) was the primary fluorine in TF while EOF(mean: 0.7 mg.kg-1, 1.8 mg.kg-1) was minor. The average amount of identified fluorine (IF) was 0.038 mg.kg-1 in hair and 0.047 mg.kg-1 in nails, accounting or 7.1% (2.6%-16%) and 3.5% (1.1%-11%) of EOF, respectively, which indicated that more than 84% of EOF was unknown. The major residue in hair and nails were medium-and short-chain PFCs,in which perfluorooctane sulfonate, perfluorooctanoic acid and perfluorononanoic acid were the main species. TF, EOF and IF levels in dyed and permed hair were significantly higher than untreated hair (P <0.05), and the concentrations of Sigma PFCs in hair and nails showed no difference between genders. With significantly higher levels of sigma PFCs and PFOS residues than hair (P <0.01), nails could potentially become a more sensitive bioindicator for the exposure level of PFCs in human.

Aromatic fluorine compounds. XI. Replacement of chlorine by fluorine in halopyridines

USGS Publications Warehouse

Finger, G.C.; Starr, L.D.; Dickerson, D.R.; Gutowsky, H.S.; Hamer, J.

1963-01-01

The ??-halogenated pyridines react with potassium fluoride in various solvents to give replacement of the ??-halogen by fluorine. A 50% yield of 2-fluoropyridine was obtained from 2-chloropyridine by heating with potassium fluoride in dimethyl sulfone or tetramethylene sulfone for twenty-one days; 2-bromopyridine gave a similar yield with a heating period of only seven days. The ??-halogens of the polyhalopyridines undergo the exchange reaction more readily than do the halogens of the ??-monohalopyridines. The proposed structures of the fluoropyridines are supported by alternate syntheses and by n.m.r. studies.

Method for converting asbestos to non-carcinogenic compounds

DOEpatents

Selby, Thomas W.

1996-01-01

Hazardous and carcinogenic asbestos waste characterized by a crystalline fibrous structure is transformed into non-carcinogenic, relatively nonhazardous, and non-crystalline solid compounds and gaseous compounds which have commercial utilization. The asbestos waste is so transformed by the complete fluorination of the crystalline fibrous silicate mineral defining the asbestos.

Method for converting asbestos to non-carcinogenic compounds

DOEpatents

Selby, T.W.

1996-08-06

Hazardous and carcinogenic asbestos waste characterized by a crystalline fibrous structure is transformed into non-carcinogenic, relatively nonhazardous, and non-crystalline solid compounds and gaseous compounds which have commercial utilization. The asbestos waste is so transformed by the complete fluorination of the crystalline fibrous silicate mineral defining the asbestos. 7 figs.

Syntheses and characterization of elpasolite-type ammonium alkali metal hexafluorometallates(III)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mi Jinxiao; Key Laboratory of New Processing Technology for Nonferrous Metals and Materials; Luo Shuming

Crystal structures of three fluorides (NH{sub 4}){sub 2}NaFeF{sub 6}, (Fe), (NH{sub 4}){sub 2}NaGaF{sub 6}, (Ga), and (NH{sub 4}){sub 2}NaCrF{sub 6}, (Cr), as well as a substituted compound [(NH{sub 4}){sub 1-x}K{sub x}]{sub 2}KAlF{sub 6} (x{approx}0.17), (Al), have been refined using single-crystal and powder X-ray diffraction techniques. All these four ammonium hexafluorides have a cubic elpasolite-type structure and crystallize in the space group Fm3-bar m with lattice constants a=8.483(3), 8.450 (3), 8.4472(2) and 8.724(3) A for compounds (Fe), (Ga), (Cr) and (Al), respectively. The effective ionic radius of the ammonium ion calculated from those compounds has a mean value of R=1.729 Amore » for CN=12. An ultraviolet-visible absorption spectrum of (NH{sub 4}){sub 2}NaCrF{sub 6}, measured at room temperature, gives a crystal field (Dq=1575 cm{sup -1}) and Racah parameters (B=758 cm{sup -1} and C=3374 cm{sup -1}). Abnormal anisotropic thermal parameters of fluorine atoms have been observed in the compound (Al), and interpreted to arise from four strong hydrogen bonds (F...H-N) that are distributed in a square form around each fluorine atom. - Graphical abstract: Abnormal anisotropic thermal parameters of fluorine atoms have been observed in the compound [(NH{sub 4}){sub 1-x}K{sub x}]{sub 2}KAlF{sub 6} (x{approx}0.17), and interpreted to arise from four strong hydrogen bonds (F...H-N) that are distributed in a square form around each fluorine atom. The endmembers' phase transitions at low temperature are believed to be caused by them.« less

Surface Partitioning and Stability of Mixed Films of Fluorinated Alcohols and Acids at the Air- Water Interface

NASA Astrophysics Data System (ADS)

Rontu, N. A.; Vaida, V.

2007-05-01

The production of fluorinated compounds over the past 50 years has had numerous industrial applications. For example, perfluorinated carboxylic acids are used in the synthesis of polymers and fire retardants, perfluoroalkyl sulfonates act as surface protectors, and fluorotelomer alcohols are incorporated into products such as paints, coatings, polymers, and adhesives. Fluorotelomer alcohols (FTOHs) are linear polyfluorinated alcohols with the formula CF3(CF2)nCH2CH2OH (n=1,3,5,...). They have been suggested as possible precursors for perfluorinated carboxylic acids and detected in the troposphere over several North American sites. Perfluorocarboxylic acids have even been detected in the arctic food chain, human blood, tissues of animals and environmental waters. We report the surface activity of fluorotelomer alcohols and perfluorinated carboxylic acids at the air-water interface by using a Langmuir trough. Isotherms of the pure compounds along with mixed films with other organic carboxylic acids were collected. The main objective of these experiments was to understand their heterogeneous chemistry by characterizing the pure and mixed films, which serves as a representative model for organic films on atmospheric surfaces such as those found on oceans and aqueous aerosols. Film properties and behavior, notably stabilization, evaporation from the subphase, and miscibility in the single-component mixtures as well as in the mixed films will be discussed. An important consequence of FTOHs and perfluorocarboxylic acids being found to partition to the air-water interface is the possibility of their transport and widespread distribution and deposition using atmospheric aerosols.

Molecular Grafting of Fluorinated and Nonfluorinated Alkylsiloxanes on Various Ceramic Membrane Surfaces for the Removal of Volatile Organic Compounds Applying Vacuum Membrane Distillation.

PubMed

Kujawa, Joanna; Al-Gharabli, Samer; Kujawski, Wojciech; Knozowska, Katarzyna

2017-02-22

Four main tasks were presented: (i) ceramic membrane functionalization (TiO 2 5 kDa and 300 kDa), (ii) extended material characterization (physicochemistry and tribology) of pristine and modified ceramic samples, (iii) evaluation of chemical and mechanical stability, and finally (iv) assessment of membrane efficiency in vacuum membrane distillation applied for volatile organic compounds (VOCs) removal from water. Highly efficient molecular grafting with four types of perfluoroalkylsilanes and one nonfluorinated agent was developed. Materials with controllable tribological and physicochemical properties were achieved. The most meaningful finding is associated with the applicability of fluorinated and nonfluorinated grafting agents. The results of contact angle, hysteresis of contact angle, sliding angle, and critical surface tension as well as Young's modulus, nanohardness, and adhesion force for grafting by these two modifiers are comparable. This provides insight into the potential applicability of environmental friendly hydrophobic and superhydrophobic surfaces. The achieved hydrophobic membranes were very effective in the removal of VOCs (butanol, methyl-tert-butyl ether, and ethyl acetate) from binary aqueous solutions in vacuum membrane distillation. The correlation between membrane effectiveness and separated solvent polarity was compared in terms of material properties and resistance to the wetting (kinetics of wetting and in-depth liquid penetration). Material properties were interpreted considering Zisman theory and using Kao diagram. The significant influence of surface chemistry on the membrane performance was noticed (5 kDa, influence of hydrophobic nanolayer and separation controlled by solution-diffusion model; 300 kDa, no impact of surface chemistry and separation controlled by liquid-vapor equilibrium).

Solid State Multinuclear Magnetic Resonance Investigation of Electrolyte Decomposition Products on Lithium Ion Electrodes

NASA Technical Reports Server (NTRS)

DeSilva, J .H. S. R.; Udinwe, V.; Sideris, P. J.; Smart, M. C.; Krause, F. C.; Hwang, C.; Smith, K. A.; Greenbaum, S. G.

2012-01-01

Solid electrolyte interphase (SEI) formation in lithium ion cells prepared with advanced electrolytes is investigated by solid state multinuclear (7Li, 19F, 31P) magnetic resonance (NMR) measurements of electrode materials harvested from cycled cells subjected to an accelerated aging protocol. The electrolyte composition is varied to include the addition of fluorinated carbonates and triphenyl phosphate (TPP, a flame retardant). In addition to species associated with LiPF6 decomposition, cathode NMR spectra are characterized by the presence of compounds originating from the TPP additive. Substantial amounts of LiF are observed in the anodes as well as compounds originating from the fluorinated carbonates.

Formation of Stoichiometric CsFn Compounds

PubMed Central

Zhu, Qiang; Oganov, Artem R.; Zeng, Qingfeng

2015-01-01

Alkali halides MX, have been viewed as typical ionic compounds, characterized by 1:1 ratio necessary for charge balance between M+ and X−. It was proposed that group I elements like Cs can be oxidized further under high pressure. Here we perform a comprehensive study for the CsF-F system at pressures up to 100 GPa, and find extremely versatile chemistry. A series of CsFn (n ≥ 1) compounds are predicted to be stable already at ambient pressure. Under pressure, 5p electrons of Cs atoms become active, with growing tendency to form Cs (III) and (V) valence states at fluorine-rich conditions. Although Cs (II) and (IV) are not energetically favoured, the interplay between two mechanisms (polyfluoride anions and polyvalent Cs cations) allows CsF2 and CsF4 compounds to be stable under pressure. The estimated defluorination temperatures of CsFn (n = 2,3,5) compounds at atmospheric pressure (218°C, 150°C, -15°C, respectively), are attractive for fluorine storage applications. PMID:25608669

Structural Insights into the Dual Activities of the Nerve Agent Degrading Organophosphate Anhydrolase/Prolidase

DTIC Science & Technology

2009-12-11

class of bimetalloenzymes that hydrolyze a variety of toxic acetylcholinesterase-inhibiting organophosphorus compounds, including fluorine ... electrophilicity of the phosphorus center. Similar interactions and functions have been proposed for the carbonyl oxygen of the scissile peptide bond...163, 261–276. 2. Mazur, A. (1946) An enzyme in animal tissues capable of hydrolyzing the phosphorus- fluorine bond of alkyl fluorophosphate. J. Biol

USSR Report, Chemistry, No. 108

DTIC Science & Technology

1983-10-21

Savel’yeva, et al.; KHIMICHESKAYA PROMYSHLENNOST’, No 7, Jul 83).., 23 Extracting Fluorine in Producing Extraction Phosphoric Acid From New Forms...the carrier under the influence of the high temperatures and chemical poisoning (primarily by fluorine compounds). Chemical poisoning decreases...source raw materials used in industry is an important re- serve in increasing food stocks. Suffice it to say that in our republic paxnt and varnish

Room-Temperature Fluorine-Induced Decrease in the Stability of Bromine and Iodine Intercalated Carbon Fibers

NASA Technical Reports Server (NTRS)

Hung, Ching-Cheh

1995-01-01

Upon exposure to room-temperature fluorine, intercalated carbon fibers (containing either bromine alone or iodine and bromine together) become heavier and less stable. For Amoco P-100 graphitized carbon fibers, which were intercalated with 18 wt percent bromine, 1 hour of fluorine exposure resulted in a large weight increase but caused only a small decrease in thermal stability. An additional 89 hours of fluorine exposure time resulted in small additional increases in fiber weight, but significant further decreases in fiber thermal stability. Such phenomena of weight increase and stability decrease do not occur if the intercalated fibers are exposed to 250 C fluorine. These observations suggest that, at room temperature, fluorine is absorbed quickly by the intercalated fibers and is intercalated slowly into the fibers. Most of the original intercalates are replaced by fluorine in the process of fluorine intercalation. In an inert environment, the bromine intercalated fibers are much more thermally stable. After 800 C vacuum heating for 2 weeks, the brominated fibers lost about 45% of their bromine, and their resistivity increased from 64 mu(Omega)-cm to a range of 95-170 mu(Omega)-cm. This is still much lower than the value of 300 mu(Omega)-cm for pristine P-100. For practical purposes, to preserve their thermal stability, brominated fibers need to be protected from exposure to fluorine at room temperature or to any intercalate at a temperature where, upon direct contact with graphite, an intercalation compound can easily be formed.

Synthesis and biological activities of fluorinated chalcone derivatives.

PubMed

Nakamura, Chika; Kawasaki, Nobuhide; Miyataka, Hideki; Jayachandran, Ezhuthachan; Kim, In Ho; Kirk, Kenneth L; Taguchi, Takeo; Takeuchi, Yoshio; Hori, Hitoshi; Satoh, Toshio

2002-03-01

We have designed and synthesized new 5-lipoxygenase inhibitors, fluorinated 3,4-dihydroxychalcones, and evaluated their biological activities with respect to antiperoxidation activity and in vitro antitumor activities. All fluorinated chalcones tested showed 5-lipoxygenase inhibition on rat basophilic leukemia-1 (RBL-1) cells and inhibitory action on Fe(3+)-ADP induced NADPH-dependent lipid peroxidation in rat liver microsomes. The potencies were comparable or better to that of the lead 3,4-dihydroxychalcone. 6-Fluoro-3,4-dihydroxy-2',4'-dimethoxy chalcone (7) was the most effective compound in the in vitro assay using a human cancer cell line panel (HCC panel) consisting of 39 systems.

Aromatic fluorine compounds. VI. Displacement of aryl fluorine in diazonium salts

USGS Publications Warehouse

Finger, G.C.; Oesterling, R.E.

1956-01-01

Several chlorofluorobenzenes have been isolated from the Schiemann synthesis of fluorobenzenes. These have been shown to be the products of two side reactions occurring during thermal decomposition of the dry benzenediazonium fluoborate salt containing coprecipitated sodium chloride, an unavoidable contaminant in large preparations involving the use of hydrochloric acid and sodium fluoborate. The major side reaction and its chloro product were unexpected; a unique displacement of fluorine ortho to the diazonium group was observed. Replacement of the diazo group with chlorine was the predicted side reaction which proved to be minor. Conditions causing the side reactions and the isolation and identification of the products are described.

Hydrogen-fluorine exchange in NaBH4-NaBF4.

PubMed

Rude, L H; Filsø, U; D'Anna, V; Spyratou, A; Richter, B; Hino, S; Zavorotynska, O; Baricco, M; Sørby, M H; Hauback, B C; Hagemann, H; Besenbacher, F; Skibsted, J; Jensen, T R

2013-11-07

Hydrogen-fluorine exchange in the NaBH4-NaBF4 system is investigated using a range of experimental methods combined with DFT calculations and a possible mechanism for the reactions is proposed. Fluorine substitution is observed using in situ synchrotron radiation powder X-ray diffraction (SR-PXD) as a new Rock salt type compound with idealized composition NaBF2H2 in the temperature range T = 200 to 215 °C. Combined use of solid-state (19)F MAS NMR, FT-IR and DFT calculations supports the formation of a BF2H2(-) complex ion, reproducing the observation of a (19)F chemical shift at -144.2 ppm, which is different from that of NaBF4 at -159.2 ppm, along with the new absorption bands observed in the IR spectra. After further heating, the fluorine substituted compound becomes X-ray amorphous and decomposes to NaF at ~310 °C. This work shows that fluorine-substituted borohydrides tend to decompose to more stable compounds, e.g. NaF and BF3 or amorphous products such as closo-boranes, e.g. Na2B12H12. The NaBH4-NaBF4 composite decomposes at lower temperatures (300 °C) compared to NaBH4 (476 °C), as observed by thermogravimetric analysis. NaBH4-NaBF4 (1:0.5) preserves 30% of the hydrogen storage capacity after three hydrogen release and uptake cycles compared to 8% for NaBH4 as measured using Sievert's method under identical conditions, but more than 50% using prolonged hydrogen absorption time. The reversible hydrogen storage capacity tends to decrease possibly due to the formation of NaF and Na2B12H12. On the other hand, the additive sodium fluoride appears to facilitate hydrogen uptake, prevent foaming, phase segregation and loss of material from the sample container for samples of NaBH4-NaF.

Effects of Processing on MOS Radiation Hardening

DTIC Science & Technology

1992-09-01

magnitude) impurity inclusion for Fluorine sources vs. Chlorine sources, many of the other beneficial effects on point defects, traps, MOS quality, etc...profiles. The addition of percent concentrations of a chlorine rates from 1 to 10 ml/nmr. This corresponded to fluorine bearing compound to the silicon...computes the partial roethane and gaseous nitrogen trifluoride . The alphatic liq- pres-ures of all the possible species in equilibrium in the uid

Neutronic experiments with fluorine rich compounds at LR-0 reactor

DOE PAGES

Losa, Evzen; Kostal, Michal; Czakoj, T.; ...

2018-06-06

Here, research on molten salt reactor (MSR) neutronics continues in Research Centre Rez (Czech Republic) with experimental work being conducted using fluoride salt that was originally used in the Molten Salt Reactor Experiment (MSRE). Previous results identified significant variations in the neutron spectrum measured in LiF-NaF salt. These variations could originate from the fluorine description in current nuclear data sets. Subsequent experiments were performed to try to confirm this phenomenon. Therefore, another fluorine-rich compound, Teflon, was used for testing. Critical experiments showed slight discrepancies in C/E-1 for both compounds, Teflon and FLIBE, and systematic overestimation of criticality was observed inmore » calculations. Different nuclear data libraries were used for data set testing. For Teflon, the overestimation is higher when using JENDL-3.3, JENDL-4, and RUSFOND-2010 libraries, all three of which share the same inelastic-to-elastic scattering cross section ratio. Calculations using other libraries (ENDF/B-VII.1, ENDF/B-VII.0, JEFF-3.2, JEFF-3.1, and CENDL-3.1) tend to be closer to the experimental value. Neutron spectrum measurement in both substances revealed structure similar to that seen in previous measurements using LiF-NaF salt, which indicates that the neutron spectrum seems to be strongly shaped by fluorine. Discrepancies between experimental and calculational results seem to be larger in the neutron energy range of 100–1300 keV than in higher energies. In the case of neutron spectrum calculation, none of the tested libraries gives overall better results than the others.« less

Neutronic experiments with fluorine rich compounds at LR-0 reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Losa, Evzen; Kostal, Michal; Czakoj, T.

Here, research on molten salt reactor (MSR) neutronics continues in Research Centre Rez (Czech Republic) with experimental work being conducted using fluoride salt that was originally used in the Molten Salt Reactor Experiment (MSRE). Previous results identified significant variations in the neutron spectrum measured in LiF-NaF salt. These variations could originate from the fluorine description in current nuclear data sets. Subsequent experiments were performed to try to confirm this phenomenon. Therefore, another fluorine-rich compound, Teflon, was used for testing. Critical experiments showed slight discrepancies in C/E-1 for both compounds, Teflon and FLIBE, and systematic overestimation of criticality was observed inmore » calculations. Different nuclear data libraries were used for data set testing. For Teflon, the overestimation is higher when using JENDL-3.3, JENDL-4, and RUSFOND-2010 libraries, all three of which share the same inelastic-to-elastic scattering cross section ratio. Calculations using other libraries (ENDF/B-VII.1, ENDF/B-VII.0, JEFF-3.2, JEFF-3.1, and CENDL-3.1) tend to be closer to the experimental value. Neutron spectrum measurement in both substances revealed structure similar to that seen in previous measurements using LiF-NaF salt, which indicates that the neutron spectrum seems to be strongly shaped by fluorine. Discrepancies between experimental and calculational results seem to be larger in the neutron energy range of 100–1300 keV than in higher energies. In the case of neutron spectrum calculation, none of the tested libraries gives overall better results than the others.« less

Fluorine conformational effects in organocatalysis: an emerging strategy for molecular design.

PubMed

Zimmer, Lucie E; Sparr, Christof; Gilmour, Ryan

2011-12-09

Molecular design strategies that profit from the intrinsic stereoelectronic and electrostatic effects of fluorinated organic molecules have mainly been restricted to bio-organic chemistry. Indeed, many fluorine conformational effects remain academic curiosities with no immediate application. However, the renaissance of organocatalysis offers the possibility to exploit many of these well-described phenomena for molecular preorganization. In this minireview, we highlight examples of catalyst refinement by introduction of an aliphatic C-F bond which functions as a chemically inert steering group for conformational control. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantification of fluorine traces in solid samples using CaF molecular emission bands in atmospheric air Laser-Induced Breakdown Spectroscopy

NASA Astrophysics Data System (ADS)

Alvarez-Llamas, C.; Pisonero, J.; Bordel, N.

2016-09-01

Direct solid determination of trace amounts of fluorine using Laser-Induced Breakdown Spectroscopy (LIBS) is a challenging task due to the low excitation efficiency of this element. Several strategies have been developed to improve the detection capabilities, including the use of LIBS in a He atmosphere to enhance the signal to background ratios of F atomic emission lines. An alternative method is based on the detection of the molecular compounds that are formed with fluorine in the LIBS plasma. In this work, the detection of CaF molecular emission bands is investigated to improve the analytical capabilities of atmospheric air LIBS for the determination of fluorine traces in solid samples. In particular, Cu matrix samples containing different fluorine concentration (between 50 and 600 μg/g), and variable amounts of Ca, are used to demonstrate the linear relationships between CaF emission signal and F concentration. Limits of detection for fluorine are improved by more than 1 order of magnitude using CaF emission bands versus F atomic lines, in atmospheric-air LIBS. Furthermore, a toothpaste powder sample is used to validate this analytical method. Good agreement is observed between the nominal and the predicted fluorine mass-content.

Chlorinated, brominated and fluorinated organic pollutants in African Penguin eggs: 30 years since the previous assessment.

PubMed

Bouwman, Hindrik; Govender, Danny; Underhill, Les; Polder, Anuschka

2015-05-01

The African Penguin population has drastically declined over the last 100 years. Changes in food availability due to over-fishing and other oceanographic changes seem to be major causes. However, it has also been 30 years since organic pollutants as a potential factor have been assessed. We analysed penguin eggs collected in 2011 and 2012 from two breeding colonies 640 km apart: Robben Island near Cape Town on the Atlantic Ocean coast, and Bird Island near Port Elizabeth on the Indian Ocean coast of South Africa. We quantified organochlorine pesticides, brominated flame retardants, and perfluorinated compounds (PFCs). Compared to 30 years ago, concentrations of ΣDDT have remained about the same or slightly lower, while ΣPCBs declined almost four-fold. The use of DDT in malaria control is unlikely to have contributed. PFCs were detected in all eggs. Indications (non-significant) of eggshell thinning associated with ΣDDT and ΣPCB was found. It seems therefore that the concentrations of measured organic pollutants the African Penguin eggs are not contributing directly to its current demise, but concerns remain about thinner shells and desiccation. Effects of combinations of compounds and newer compounds cannot be excluded, as well as more subtle effects on reproduction, development, and behaviour. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fabrication of hydrophobic fluorinated silica-polyamide thin film nanocomposite reverse osmosis membranes with dramatically improved salt rejection.

PubMed

Pang, Ruizhi; Zhang, Kaisong

2018-01-15

Thin film nanocomposite reverse osmosis (TFN RO) membranes incorporated with hydrophilic nanoparticles show a potential problem that the salt rejection can not be improved significantly. In this study, novel TFN RO membranes incorporated with hydrophobic fluorinated silica nanoparticles were fabricated to improve the salt rejection. Fluorinated silica nanoparticles were well dispersed in organic phase during the interfacial polymerization (IP) process. The TFN RO membranes were characterized with attenuated total reflectance infra-red, field emission scanning electron microscopy, atomic force microscopy and water contact angle measurements. The preparation conditions of TFN RO membranes, including IP reaction time, organic solvent removal time, and fluorinated silica loading, were optimized by characterizing desalination performance using 2000ppm NaCl aqueous solution at 1.55MPa and 25°C. The salt rejection increased significantly from 96.0% without fluorinated silica nanoparticles to 98.6% with the optimal 0.12% (w/v) fluorinated silica nanoparticles, while the water flux decreased slightly from 0.99m 3 /m 2 /day to 0.93m 3 /m 2 /day. This study demonstrated the potential use of hydrophobic nanoparticles in high-performance TFN RO membranes. Copyright © 2017 Elsevier Inc. All rights reserved.

New Horizons in C-F Activation by Main Group Electrophiles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ozerov, Oleg V.

2016-02-13

This technical report describes progress on the DOE sponsored project "New Horizons in C-F Activation by Main Group Electrophiles" during the period of 09/15/2010 – 08/31/2015. The main goal of this project was to develop improved catalysts for conversion of carbon-fluorine bonds in potentially harmful compounds. The approach involved combining of a highly reactive positively charged main-group compound with a highly unreactive negatively charged species (anions) as a way to access potent catalysts for carbon-fluorine bond activation. This report details progress made in improving synthetic pathways to a variety of new anions with improved properties and analysis of their potentialmore » in catalysis.« less

Theoretical study of stability and charge-transport properties of coronene molecule and some of its halogenated derivatives: A path to ambipolar organic-based materials?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sancho-García, J. C., E-mail: jc.sancho@ua.es; Pérez-Jiménez, A. J., E-mail: aj.perez@ua.es

2014-10-07

We have carefully investigated the structural and electronic properties of coronene and some of its fluorinated and chlorinated derivatives, including full periphery substitution, as well as the preferred orientation of the non-covalent dimer structures subsequently formed. We have paid particular attention to a set of methodological details, to first obtain single-molecule magnitudes as accurately as possible, including next the use of modern dispersion-corrected methods to tackle the corresponding non-covalently bound dimers. Generally speaking, this class of compounds is expected to self-assembly in neighboring π-stacks with dimer stabilization energies ranging from –20 to –30 kcal mol{sup −1} at close distances around 3.0–3.3more » Å. Then, in a further step, we have also calculated hole and electron transfer rates of some suitable candidates for ambipolar materials, and corresponding charge mobility values, which are known to critically depend on the supramolecular organization of the samples. For coronene and per-fluorinated coronene, we have found high values for their hopping rates, although slightly smaller for the latter due to an increase (decrease) of the reorganization energies (electronic couplings)« less

Photovoltaic Small Molecules of TPA(FxBT-T-Cz)3: Tuning Open-Circuit Voltage over 1.0 V for Their Organic Solar Cells by Increasing Fluorine Substitution.

PubMed

Wang, Qiong; Duan, Linrui; Tao, Qiang; Peng, Wenhong; Chen, Jianhua; Tan, Hua; Yang, Renqiang; Zhu, Weiguo

2016-11-09

To simultaneously improve both open-circuit voltage (V oc ) and short-circuit current density (J sc ) for organic solar cells, a novel D(A-π-Ar) 3 type of photovoltaic small molecules of TPA(F x BT-T-3Cz) 3 was designed and synthesized, which contain central triphenylamine (TPA), terminal carbazole (Cz), armed fluorine-substituted benzothiadiazole (F x BT, where x = 1 or 2), and bridged thiophene (T) units. A narrowed ultraviolet-visible absorption and a decreasing highest occupied molecular orbital energy level were observed from TPA(F 1 BT-T-3Cz) 3 to TPA(F 2 BT-T-3Cz) 3 with increasing fluorine substitution. However, the TPA(F 2 BT-T-3Cz) 3 /PC 71 BM-based solar devices showed a rising V oc of 1.01 V and an enhanced J sc of 10.84 mA cm -2 as well as a comparable power conversion efficiency of 4.81% in comparison to the TPA(F 1 BT-T-3Cz) 3 /PC 71 BM-based devices. Furthermore, in comparison to the parent TPA(BT-T-3Cz) 3 molecule without fluorine substitution, the fluorine-substituted TPA(F x BT-T-3Cz) 3 molecules exhibited significantly incremental V oc and J sc values in their bulk heterojunction organic solar cells, owing to fluorine incorporation in the electron-deficient benzothiadiazole unit.

Performance and limits of liquid chromatography isotope ratio mass spectrometry system for halogenated compounds

NASA Astrophysics Data System (ADS)

Gilevska, Tetyana; Gehre, Matthias; Richnow, Hans

2014-05-01

Compound Specific Isotope Analysis (CSIA) has been an important step for the assessment of the origin and fate of compounds in environmental science.[1] Biologically or pharmaceutically important compounds often are not amenable for gas chromatographic separation because of high polarity and lacking volatility, thermostability. In 2004 liquid chromatography isotope ratio mass spectrometry (LC-IRMS) became commercially available. LC-IRMS system intent a quantitative conversion of analytes separation into CO2 via wet oxidation with sodium persulfate in the presence of phosphoric acid while analytes are still dissolved in the aqueous liquid phase.[2] The aim of this study is to analyze the oxidation capacity of the interface of the LC-IRMS system and determine which parameters could improve oxidation of compounds which are resistant to persulfate oxidation. Oxidation capacity of the liquid chromatography isotope ratio mass spectrometry system was tested with halogenated acetic acid and a set of aromatic compounds with different substitutes. Acetic acid (AA) was taken as a model compound for complete oxidation and compared to the oxidation of other analytes on a molar basis. Correct values were obtained for di- and mono chlorinated and fluorinated and also for tribrominated acetic acid and for all studied aromatic compounds. Incomplete oxidation for trichloroacetic (TCAA) and trifluoroacetic (TFAA) acid was revealed with lower recovery compared to acetic acid and isotope fractionation leading to depleted carbon isotope composition compared to values obtained with an elementary analyzer connected to an isotope mass spectrometer Several optimization steps were tried in order to improve the oxidation of TCAA and TFAA: (i) increasing the concentration of the oxidizing agent, (ii) variation of flow rate of the oxidizing and acid solution, (iii) variation of flow rate of liquid chromatography pump (iv) addition of a catalyzer. These modifications lead to longer reaction time in the coil and increase in the concentration of radical but complete combustion of highly chlorinated or fluorinated compounds was not achieved. Due to these findings the limit for a LC-IRMS system for similar structure compounds can be predicted. 1. Elsner, M., et al., Current challenges in compound-specific stable isotope analysis of environmental organic contaminants. Analytical and Bioanalytical Chemistry, 2012. 403(9): p. 2471-2491. 2. Krummen, M., et al., A new concept for isotope ratio monitoring liquid chromatography/mass spectrometry. Rapid Communications in Mass Spectrometry, 2004. 18(19): p. 2260-2266.

NEW CHEMICAL ALTERNATIVES FOR THE PROTECTION OF STRATOSPHERIC OZONE

EPA Science Inventory

The report gives results of a study that focused on the investigation of fluorinated derivatives of propane and butane to determine if synthesis routes of such compounds were feasible and economical and to measure the physical properties needed to evaluate the compounds as altern...

MAMMALIAN METABOLISM AND DISTRIBUTION OF PERFLUOROOCTYL ETHANOL (8-2 TELOMER ALCOHOL) AND ITS OXIDATION METABOLITES

EPA Science Inventory

Perfluorinated compounds have been shown to be globally distributed, bioaccumulative, persistent and potentially toxic. It has been hypothesized that many precursor fluorinated compounds, including the telomer alcohols, degrade or metabolize to the common metabolite PFOA.

Keeping Mars warm with new super greenhouse gases

PubMed Central

Gerstell, M. F.; Francisco, J. S.; Yung, Y. L.; Boxe, C.; Aaltonee, E. T.

2001-01-01

Our selection of new super greenhouse gases to fill a putative “window” in a future Martian atmosphere relies on quantum-mechanical calculations. Our study indicates that if Mars could somehow acquire an Earth-like atmospheric composition and surface pressure, then an Earth-like temperature could be sustained by a mixture of five to seven fluorine compounds. Martian mining requirements for replenishing the fluorine could be comparable to current terrestrial extraction. PMID:11226208

Research in Energetic Compounds.

DTIC Science & Technology

1981-01-01

The ring is thus amenable to electrophilic opening. Efforts to polymerize 3, 3-dinitrooxetane will be continued. An intermediate In the preparation of...r- nitronate salts and formaldehyde.2 This reaction is ported to give a stable dialkoxide salt. In order to explore markedly inhibited by a fluorine ...a to nitro as a manifes- further the chemistry of 2-fluoro-2-nitro-I,3-propanediol, tation of the " fluorine effect" or the destabilization of a we

Looking for the new preparations for antibacterial therapy III. New antimicrobial agents from the quinolones group in clinical trials.

PubMed

Karpiuk, Izabela; Tyski, Stefan

2013-01-01

There is an essential need for searching for the new compounds effective in the treatment of infections caused by multidrug-resistant bacteria. This paper is the third part of a series associated with the exploration of new antibacterial agents and it discusses the compounds belonging to the group of quinolones and substances possessing a hybrid structure composed of the quinolone molecule and other compounds. Eleven new substances at the stage of clinical trials are presented. Three of them belong to the group of non-fluorinated quinolone (nemonoxacin, ozenoxacin and KRP-AM 1977X), while six are the quinolones containing fluorine atom at 6 position of the carbon atom in the quinoline ring (zabofloxacin, finafloxacin, delafloxacin, JNJ-Q2, WCK771 and KPI-10). The remaining two compounds possess a hybrid construction composed of the quinolone structure and other molecules (cadazolid and CBR-2092). There is a chance in the near future, that the presented compounds can extend the range of existing antibacterial drugs and provide an alternative to currently available medicinal products.

High-performance vertical organic transistors.

PubMed

Kleemann, Hans; Günther, Alrun A; Leo, Karl; Lüssem, Björn

2013-11-11

Vertical organic thin-film transistors (VOTFTs) are promising devices to overcome the transconductance and cut-off frequency restrictions of horizontal organic thin-film transistors. The basic physical mechanisms of VOTFT operation, however, are not well understood and VOTFTs often require complex patterning techniques using self-assembly processes which impedes a future large-area production. In this contribution, high-performance vertical organic transistors comprising pentacene for p-type operation and C60 for n-type operation are presented. The static current-voltage behavior as well as the fundamental scaling laws of such transistors are studied, disclosing a remarkable transistor operation with a behavior limited by injection of charge carriers. The transistors are manufactured by photolithography, in contrast to other VOTFT concepts using self-assembled source electrodes. Fluorinated photoresist and solvent compounds allow for photolithographical patterning directly and strongly onto the organic materials, simplifying the fabrication protocol and making VOTFTs a prospective candidate for future high-performance applications of organic transistors. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method for fluorination of actinide fluorides and oxyfluorides thereof using O.sub.2 F.sub.2

DOEpatents

Eller, Phillip G.; Malm, John G.; Penneman, Robert A.

1988-01-01

Method for fluorination of actinides and fluorides and oxyfluorides thereof using O.sub.2 F.sub.2 which generates actinide hexafluorides, and for removal of actinides and compounds thereof from surfaces upon which they appear as unwanted deposits. The fluorinating agent, O.sub.2 F.sub.2, has been observed to readily perform the above-described tasks at sufficiently low temperatures that there is virtually no damage to the containment vessels. Moreover, the resulting actinide hexafluorides are thereby not destroyed by high temperature reactions with the walls of the reaction vessel. Dioxygen difluoride is easily prepared, stored and transferred to the desired place of reaction.

Method for fluorination of actinide fluorides and oxyfluorides thereof using O[sub 2]F[sub 2

DOEpatents

Eller, P.G.; Malm, J.G.; Penneman, R.A.

1988-11-08

Method is described for fluorination of actinides and fluorides and oxyfluorides thereof using O[sub 2]F[sub 2] which generates actinide hexafluorides, and for removal of actinides and compounds thereof from surfaces upon which they appear as unwanted deposits. The fluorinating agent, O[sub 2]F[sub 2], has been observed to readily perform the above-described tasks at sufficiently low temperatures that there is virtually no damage to the containment vessels. Moreover, the resulting actinide hexafluorides are thereby not destroyed by high temperature reactions with the walls of the reaction vessel. Dioxygen difluoride is easily prepared, stored and transferred to the desired place of reaction.

Controlled Formation of Mixed Nanoscale Domains of High Capacity Fe 2O 3–FeF 3 Conversion Compounds by Direct Fluorination

DOE PAGES

Zhou, Hui; Ruther, Rose E.; Adcock, Jamie; ...

2015-02-22

In this paper, we report a direct fluorination method under fluorine gas atmosphere using a fluidized bed reactor for converting nanophase iron oxide (n-Fe 2O 3) to an electrochemically stable and higher energy density iron oxyfluoride/fluoride phase. Interestingly, no noticeable bulk iron oxyfluoride phase (FeOF) phase was observed even at fluorination temperature close to 300 °C. Instead, at fluorination temperatures below 250 °C, scanning transmission electron microscopy coupled with electron energy loss spectroscopy (STEM-EELS) and X-ray photoelectron spectroscopy (XPS) analysis showed surface fluorination with nominal composition, Fe 2O 3-xF 2x (x < 1). At fluorination temperatures of 275 °C, STEM-EELSmore » results showed porous interconnected nanodomains of FeF 3 and Fe 2O 3 coexisting within the same particle, and overall the particles become less dense after fluorination. We performed potentiometric intermittent titration and electrochemical impedance spectroscopy studies to understand the lithium diffusion (or apparent diffusion) in both the oxyfluoride and mixed phase FeF 3 + Fe 2O 3 composition, and correlate the results to their electrochemical performance. Finally and further, we analyze from a thermodynamical perspective, the observed formation of the majority fluoride phase (77% FeF 3) and the absence of the expected oxyfluoride phase based on the relative formation energies of oxide, fluoride, and oxyfluorides.« less

A method to remove intercalates from bromine and iodine intercalated carbon fibers

NASA Technical Reports Server (NTRS)

Hung, Ching-Cheh

1993-01-01

Upon exposure to room-temperature fluorine, intercalated carbon fibers (containing either bromine alone or iodine and bromine together) become heavier and less stable. For Amoco P-100 graphitized carbon fibers which were intercalated with 18 percent bromine by weight, 1 hr of fluorine exposure results in a large weight increase, but causes only a small decrease in thermal stability. More than l hr of fluorine exposure time results in small additional increases in fiber weight, but significant further decreases in fiber thermal stability. Such phenomena do not occur if the fluorine exposure is at 250 C. These observations suggest the mechanism that at room temperature, fluorine is absorbed quickly by the intercalated fibers and intercalated slowly into the fibers. Most of the original intercalates are replaced by fluorine in the process of fluorine intercalation. Under an inert environment, the bromine intercalated fibers are much more thermally stable. After 800 C vacuum heating for two weeks, the brominated fibers lost about 45 percent of their bromine, and their resistivity increased from 64 omega-cm to a range of 95 to 170 micro omega-cm. This is still much lower than the 300 micro omega-cm value for pristine P-100. For practical purposes, in order to preserve their thermal stability, brominated fibers need to be protected from exposure to fluorine at room temperature, or to any intercalate at a temperature where, upon direct contact to graphite, an intercalation compound can easily be formed.

Alkaline and alkaline earth metal phosphate halides and phosphors

DOEpatents

Lyons, Robert Joseph; Setlur, Anant Achyut; Cleaver, Robert John

2012-11-13

Compounds, phosphor materials and apparatus related to nacaphite family of materials are presented. Potassium and rubidium based nacaphite family compounds and phosphors designed by doping divalent rare earth elements in the sites of alkaline earth metals in the nacaphite material families are descried. An apparatus comprising the phosphors based on the nacaphite family materials are presented herein. The compounds presented is of formula A.sub.2B.sub.1-yR.sub.yPO.sub.4X where the elements A, B, R, X and suffix y are defined such that A is potassium, rubidium, or a combination of potassium and rubidium and B is calcium, strontium, barium, or a combination of any of calcium, strontium and barium. X is fluorine, chlorine, or a combination of fluorine and chlorine, R is europium, samarium, ytterbium, or a combination of any of europium, samarium, and ytterbium, and y ranges from 0 to about 0.1.

Degradation of Perfluorooctanoic Acid and Perfluoroctane Sulfonate by Enzyme Catalyzed Oxidative Humification Reactions

NASA Astrophysics Data System (ADS)

Huang, Q.

2016-12-01

Poly- and perfluoroalkyl substances (PFASs) are alkyl based chemicals having multiple or all hydrogens replaced by fluorine atoms, and thus exhibit high thermal and chemical stability and other unusual characteristics. PFASs have been widely used in a wide variety of industrial and consumer products, and tend to be environmentally persistent. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are two representative PFASs that have drawn particular attention because of their ubiquitous presence in the environment, resistance to degradation and toxicity to animals. This study examined the decomposition of PFOA and PFOS in enzyme catalyzed oxidative humification reactions (ECOHR), a class of reactions that are ubiquitous in the environment involved in natural organic humification. Reaction rates and influential factors were examined, and high-resolution mass spectrometry was used to identify possible products. Fluorides and partially fluorinated compounds were identified as likely products from PFOA and PFOS degradation, which were possibly formed via a combination of free radical decomposition, rearrangements and coupling processes. The findings suggest that PFOA and PFOS may be transformed during humification, and ECOHR can potentially be used for the remediation of these chemicals.

On the Usage of Locally Dense Basis Sets in the Calculation of NMR Indirect Nuclear Spin-Spin Coupling Constants

NASA Astrophysics Data System (ADS)

Sanchez, Marina; Provasi, Patricio F.; Aucar, Gustavo A.; Sauer, Stephan P. A.

Locally dense basis sets (

Resolving intramolecular-distortion changes induced by the partial fluorination of pentacene adsorbed on Cu(111)

NASA Astrophysics Data System (ADS)

Franco-Cañellas, Antoni; Wang, Qi; Broch, Katharina; Shen, Bin; Gerlach, Alexander; Bettinger, Holger F.; Duhm, Steffen; Schreiber, Frank

2018-04-01

We experimentally quantify the molecular bending of a partially fluorinated pentacene (PEN) compound, namely 2,3,9,10-tetrafluoropentacene (F4PEN), adsorbed on Cu(111). By means of the x-ray standing wave (XSW) technique, we directly measure the adsorption distance of three inequivalent carbon sites, the fluorine atoms as well as the total and backbone carbon average adsorption distances. The precise positioning of different sites within the carbon core allows us to resolve two adsorption behaviors, namely a PEN-like strong coupling between the backbone and the substrate, and a repulsive interaction involving the fluorinated short molecular edges, which are 0.91 ±0.09 Å above the central benzene ring. This finding is further supported by additional electronic and in-plane-structure measurements, thus showing that the selective fluorination of a PEN molecule has only a local conformational effect and it is not sufficient to modify its interface properties. Yet, in the multilayer regime, the electronic and growth properties of the film differ completely from those of PEN and its perfluorinated derivative.

Impact of Fluorine Atoms on Perylene Diimide Derivative for Fullerene-Free Organic Photovoltaics.

PubMed

Zhao, Liang; Sun, Hua; Liu, Xiaoyuan; Liu, Changmei; Shan, Haiquan; Xia, Jiuxu; Xu, Zongxiang; Chen, Fei; Chen, Zhi-Kuan; Huang, Wei

2017-08-17

The incorporation of fluorine atoms in organic semiconducting materials has attracted much attention recently due to its unique function to manipulate the molecular packing, film morphology and molecular energy levels. In this work, two perylenediimide (PDI) derivatives FPDI-CDTph and FPDI-CDTph2F were designed and synthesized to investigate the impact of fluorination on non-fullerene acceptors. Both FPDI-CDTph and FPDI-CDTph2F exhibited strong and broad absorption profiles, suitable lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) energy levels, and good electron transport ability. Compared with FPDI-CDTph, the fluorinated acceptor (FPDI-CDTph2F) afforded an optimal bulk heterojunction morphology with an interconnected and nanoscale phase separated structure that allowed more efficient exciton dissociation and balanced charge transport. Consequently, organic solar cells based on FPDI-CDTph2F showed a much higher power conversion efficiency (PCE) of 6.03 % than that of FPDI-CDTph based devices (4.10 %) without any post-fabrication treatment. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Oxidative desulfurization-fluorination of thioethers. Application for the synthesis of fluorinated nitrogen containing building blocks.

PubMed

Hugenberg, Verena; Fröhlich, Roland; Haufe, Günter

2010-12-21

An oxidative desulfurization-fluorination protocol has been used to synthesize (2S)-2-(difluoromethyl)-N-tosylpyrrolidine (6a) and (2S)-2-(trifluoromethyl)-N-tosylpyrrolidine (7a) from the (2S)-prolinol-derived (2S)-2-(4-chlorophenylthiomethyl)-N-tosylpyrrolidine (9) or (2S)-2-(dithian-2-yl)-N-tosylpyrrolidine (5). Efforts to prepare 3,3-difluoroalanine similarly from an N-protected S-aryl-cysteine ester 17 gave only traces of the target compound 18. Instead, an unique N-(α,α-difluorobenzyl)-N-α',α'-dibromoglycine ester 19 was formed by an unprecedented sequence of reaction steps. A plausible mechanism is suggested involving a sulfur-assisted deoxygenation-difluorination of an imino oxygen and a haloform reaction like carbon-carbon bond fission as key-steps. Efforts to prepare (2S)-2-(fluoromethyl)-N-tosylpyrrolidine (12) from (2S)-N-tosylprolinol (3) by treatment with Fluolead™ (1-tert-butyl-4-trifluorosulfanyl-3,5-dimethylbenzene) gave only 5% of the target compound, but 95% of (3R)-3-fluoro-N-tosylpiperidine (11a) by ring enlargement.

The design of an environmentally relevant mixture of persistent organic pollutants for use in in vivo and in vitro studies.

PubMed

Berntsen, Hanne Friis; Berg, Vidar; Thomsen, Cathrine; Ropstad, Erik; Zimmer, Karin Elisabeth

2017-01-01

Amongst the substances listed as persistent organic pollutants (POP) under the Stockholm Convention on Persistent Organic Pollutants (SCPOP) are chlorinated, brominated, and fluorinated compounds. Most experimental studies investigating effects of POP employ single compounds. Studies focusing on effects of POP mixtures are limited, and often conducted using extracts from collected specimens. Confounding effects of unmeasured substances in such extracts may bias the estimates of presumed causal relationships being examined. The aim of this investigation was to design a model of an environmentally relevant mixture of POP for use in experimental studies, containing 29 different chlorinated, brominated, and perfluorinated compounds. POP listed under the SCPOP and reported to occur at the highest levels in Scandinavian food, blood, or breast milk prior to 2012 were selected, and two different mixtures representing varying exposure scenarios constructed. The in vivo mixture contained POP concentrations based upon human estimated daily intakes (EDIs), whereas the in vitro mixture was based upon levels in human blood. In addition to total in vitro mixture, 6 submixtures containing the same concentration of chlorinated + brominated, chlorinated + perfluorinated, brominated + perfluorinated, or chlorinated, brominated or perfluorinated compounds only were constructed. Using submixtures enables investigating the effect of adding or removing one or more chemical groups. Concentrations of compounds included in feed and in vitro mixtures were verified by chemical analysis. It is suggested that this method may be utilized to construct realistic mixtures of environmental contaminants for toxicity studies based upon the relative levels of POP to which individuals are exposed.

Synthesis and Structural Characterization of New High-Valent Inorganic Fluorine Compounds and their Oxidizing Properties. Volume 2

DTIC Science & Technology

1992-02-01

a definitely related Government procurement operation, the fact ti ’it the Govern- ment may have formulated, furnished, or in any way supplied the...rapid rcxprired in which krypton is bonded to an clement other than acquisition of the free induction decays with a high-field pulse fluorine...spectroscopy is the single most powerful technique used in the structural characterization of noble gas species. This technique is especially useful in

Nitrodifluoraminoterphenyl compounds and processes

DOEpatents

Lerom, M.W.; Peters, H.M.

1975-07-08

This patent relates to the nitrodifluoraminoterphenyl compounds: 3,3''-bis (difluoramino)-2,2'' 4,4', 4'',6,6',6''-octanitro-m-terphenyl (DDONT) and 3,3''-bis(difluoramino)-2,2',2''4,4',4'',6,6',6''-nonanitro-m-terphenyl (DDNONA). Procedures are described wherein diamino precursors of the indicated compounds are prepared and the final compounds are obtained by a fluorination operation. The compounds are highly energetic and suitable for use as explosives and particularly in exploding bridge wire (EBW) detonators. (auth)

NMR and X-ray structural characterization and conformational aspects of fluorinated (5Z)-3-benzil-5-arylidenofuran-2(5H)-ones

NASA Astrophysics Data System (ADS)

Teixeira, R. R.; Barbosa, L. C. A.; Kabeshov, M. A.; Maltha, C. R. A.; Corrêa, R. S.; Doriguetto, A. C.

2014-10-01

Herein we describe structural insights of (5Z)-3-benzyl-5-(2-fluorobenzylidene)furan-2(5H)-one (6) and (5Z)-3-benzyl-5-(pentafluorobenzylidene)furan-2(5H)-one (7), γ-alkylidenebutenolides analogues of the natural products nostoclides. Their structures were investigated by NMR spectroscopy and X-ray crystallography. The stereochemistry of the exocyclic double bond of these fluorinated compounds was determined to be Z by NMR analysis and confirmed by X-ray data. Compounds 6 and 7 crystallized in the monoclinic crystal system P21/c group. A comparison between structural features of (6) and (7) and nostoclide derivatives previously published by us is described.

Fluorine-Induced Chemiluminescence Detection of Biologically Methylated Tellurium, Selenium, and Sulfur Compounds and Methyldithiocarbhydrazide as a Formaldehyde Derivatization Reagent

NASA Astrophysics Data System (ADS)

Chasteen, Thomas Girard

1990-01-01

The first part of this dissertation describes capillary chromatography coupled to a fluorine-induced chemiluminescence detector as a sensitive method by which biologically methylated metalloids can be determined in the presence of high concentrations of potentially interfering molecules. With a wide linear range and excellent sensitivity, this method was applied to the detection of dimethyl selenide (DMSe), dimethyl diselenide (DMDSe), and dimethyl telluride (DMTe), often found in biological environments in the presence of interfering methylated sulfur gases, such as methanethiol, dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide. Detection limits for DMSe, DMDSe, and DMTe were 30, 9, and 7 picograms, respectively. This DMTe detection limit is the lowest reported to date for a volatile tellurium gas. A variety of selenium-resistant bacteria emitted mixtures of methylated sulfur/selenium gases when dosed with inorganic selenium salts in the presence of sulfur containing growth media. One of the gases detected was dimethyl selenenyl sulfide, CH_3SeSCH _3, reported here for the first time in headspace above microorganisms. In addition, this detector responded to reduced phosphorus compounds such as phosphine. The detection limit for this compound was 2.8 picograms. Detection limits for alkylated phosphines trimethyl and triethyl phosphine were 0.5 and 17 picograms respectively, based on the relative response of these compounds compared to dimethyl sulfide. This method can be used for the simultaneous determination of methylated sulfur, selenium, tellurium compounds found in biological systems. Part II of this dissertation describes work with methyldithiocarbhydrazide, a compound that has been synthesized for use as a derivatization reagent to capture formaldehyde in the gas phase. Chosen for its ability to react in a manner similar to 2,4-dinitrophenylhydrazine, this molecule was selected based on two structural characteristics: a hydrazine tag to react with and thereby capture carbonyls and a methyl sulfide group to allow for sensitive detection by fluorine-induced chemiluminescence. Although in the final analysis methyldithiocarbohydrazide failed as a successful means by which formaldehyde can be determined using gas chromatography in conjunction with fluorine-induced chemiluminescence, it did successfully derivatize formaldehyde in both solution and the gas phase without the need for low pH conditions.

SYNTHESIS OF HIGHLY FLUORINATED CHLOROFORMATES AND THEIR USE AS DERIVATIZING AGENTS FOR HYDROPHILIC COMPOUNDS AND DRINKING WATER DISINFECTION BY-PRODUCTS

EPA Science Inventory

A rapid, safe and efficient procedure was developed to synthesize perfluorinated chloroformates in the small scale generally required to perform analytical derivatizations. This new family of derivatizing agents allows straightforward derivatization of highly polar compounds, co...

40 CFR 60.221 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Phosphate Fertilizer Industry... ammonia. (b) Total fluorides means elemental fluorine and all fluoride compounds as measured by reference...

40 CFR 60.221 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Phosphate Fertilizer Industry... ammonia. (b) Total fluorides means elemental fluorine and all fluoride compounds as measured by reference...

40 CFR 60.221 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Phosphate Fertilizer Industry... ammonia. (b) Total fluorides means elemental fluorine and all fluoride compounds as measured by reference...

40 CFR 60.221 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Phosphate Fertilizer Industry... ammonia. (b) Total fluorides means elemental fluorine and all fluoride compounds as measured by reference...

40 CFR 60.221 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Phosphate Fertilizer Industry... ammonia. (b) Total fluorides means elemental fluorine and all fluoride compounds as measured by reference...

Fiber-coupled LED gas sensor and its application to online monitoring of ecoefficient dielectric insulation gases in high-voltage circuit breakers.

PubMed

Kramer, Axel; Over, Daniel; Stoller, Patrick; Paul, Thomas A

2017-05-20

Novel dielectric insulation gases used as alternatives to sulfur hexafluoride in gas-insulated switchgear (GIS) include several mixtures containing fluorinated organic compounds. We developed a fiber-optic analyzer enabling concentration measurement of fluoroketones used in medium- and high-voltage switchgear applications by ABB, with concurrent compensation of disturbing effects caused by dust and dirt. The sensor enables measurements in GIS and even in operating high-voltage circuit breakers. The online availability of concentration readings of fluoroketones is important for development tests, but can also be applied for monitoring or diagnostics of field installations.

Membrane separation of ionic liquid solutions

DOEpatents

Campos, Daniel; Feiring, Andrew Edward; Majumdar, Sudipto; Nemser, Stuart

2015-09-01

A membrane separation process using a highly fluorinated polymer membrane that selectively permeates water of an aqueous ionic liquid solution to provide dry ionic liquid. Preferably the polymer is a polymer that includes polymerized perfluoro-2,2-dimethyl-1,3-dioxole (PDD). The process is also capable of removing small molecular compounds such as organic solvents that can be present in the solution. This membrane separation process is suitable for drying the aqueous ionic liquid byproduct from precipitating solutions of biomass dissolved in ionic liquid, and is thus instrumental to providing usable lignocellulosic products for energy consumption and other industrial uses in an environmentally benign manner.

Exploration of fluorine chemistry at the multidisciplinary interface of chemistry and biology.

PubMed

Ojima, Iwao

2013-07-05

Over the last three decades, my engagement in "fluorine chemistry" has evolved substantially because of the multidisciplinary nature of the research programs. I began my research career as a synthetic chemist in organometallic chemistry and homogeneous catalysis directed toward organic synthesis. Then, I was brought into a very unique world of "fluorine chemistry" in the end of 1970s. I started exploring the interface of fluorine chemistry and transition metal homogeneous catalysis first, which was followed by amino acids, peptides, and peptidomimetics for medicinal chemistry. Since then, I have been exploring the interfaces of fluorine chemistry and multidisciplinary fields of research involving medicinal chemistry, chemical biology, cancer biology, and molecular imaging. This perspective intends to cover my fruitful endeavor in the exploration of fluorine chemistry at the multidisciplinary interface of chemistry and biology in a chronological order to show the evolution of my research interest and strategy.

Exploration of Fluorine Chemistry at the Multidisciplinary Interface of Chemistry and Biology

PubMed Central

Ojima, Iwao

2013-01-01

Over the last three decades, my engagement in “fluorine chemistry” has evolved substantially, because of the multidisciplinary nature of the research programs. I began my research career as a synthetic chemist in organometallic chemistry and homogeneous catalysis directed toward organic synthesis. Then, I was brought into a very unique world of “fluorine chemistry” in the end of 1970s. I started exploring the interface of fluorine chemistry and transition metal homogeneous catalysis first, which was followed by amino acids, peptides, and peptidomimetics for medicinal chemistry. Since then, I have been exploring the interfaces of fluorine chemistry and multidisciplinary fields of research involving medicinal chemistry, chemical biology, cancer biology and molecular imaging. This perspective intends to cover my fruitful endeavor in the exploration of fluorine chemistry at the multidisciplinary interface of chemistry and biology in a chronological order to show the evolution of my research interest and strategy. PMID:23614876

Self-organized nitrogen and fluorine co-doped titanium oxide nanotube arrays with enhanced visible light photocatalytic performance.

PubMed

Li, Qi; Shang, Jian Ku

2009-12-01

Self-organized nitrogen and fluorine co-doped titanium oxide (TiONF) nanotube arrays were created by anodizing titanium foil in a fluoride and ammoniate-based electrolyte, followed by calcination of the amorphous nanotube arrays under a nitrogen protective atmosphere for crystallization. TiONF nanotube arrays were found to have enhanced visible light absorption capability and photodegradation efficiency on methylene blue under visible light illumination over the TiO(2) nanotube arrays. The enhancement was dependent on both the nanotube structural architecture and the nitrogen and fluorine co-doping effect. TiONF nanotube arrays promise a wide range of technical applications, especially for environmental applications and solar cell devices.

Spectral properties of nanocomposites based on fluorine-containing polymer and gold nanoparticles

NASA Astrophysics Data System (ADS)

Barmina, E. V.; Mel’nik, N. N.; Rakov, I. I.; Ivanov, V. E.; Simakin, A. V.; Gudkov, S. V.; Shafeev, G. A.

2018-04-01

The optical properties of nanocomposites of gold nanoparticles and fluorine-containing polymer have been studied. Gold nanoparticles were obtained by laser ablation of gold or terbium targets in organic solvents. The thus formed colloidal solutions were used to prepare nanocomposites of gold nanoparticles in polymer matrices of transparent and colorless fluorine-containing polymer. The polymer matrix is found to promote aggregation of nanoparticles of metal under study into elongated chains. In turn, metal nanoparticles influence on the polymer matrix. Gold nanoparticles amplify the Raman signal of the polymer matrix. In addition, the Raman spectra of nanocomposites indicate aggregation of disordered carbon around the nanoparticles obtained by laser ablation in organic solvents.

Cytoprotective Effect of Caffeic Acid Phenethyl Ester (CAPE) and Catechol Ring-Fluorinated CAPE Derivatives Against Menadione-Induced Oxidative Stress in Human Endothelial Cells

DTIC Science & Technology

2006-03-31

chlorogenic acid , and rosmari- nic acid did not display any cytoprotective effect in this assay at 15 lM (data not shown). Within the same pas- sage of HUVEC...Cytoprotective effect of caffeic acid phenethyl ester (CAPE) and catechol ring-fluorinated CAPE derivatives against menadione-induced oxidative...accepted 13 March 2006 Available online 31 March 2006 Abstract—Caffeic acid phenethyl ester (CAPE), a natural polyphenolic compound with many

A Model Action Pla to Reduce the Use and Release of CFCs in Air- Conditioning and Refrigeration Systems

DTIC Science & Technology

1992-09-01

ccmpounds discussed in the research. Chiorofluorocarbon nolecules consist entirely of chlorine, fluorine, and carbon atoms. When a hydrogen atm is bonded...of carbon, hydrogen, and fluorine atoms contained in the compound. Chlorine atms miake up the remaining available bond sites. For exanple, CFC-l1...HCFC-22 has been successfully tested as a substitute for CFC-12 and CFC-502 in retrofitted supermarket refrigeration systems. There is same loss of

Neurotoxic effects of perfluoroalkylated compounds: mechanisms of action and environmental relevance.

PubMed

Mariussen, Espen

2012-09-01

Perfluoroalkylated compounds (PFCs) are used in fire-fighting foams, treatment of clothes, carpets and leather products, and as lubricants, pesticides, in paints and medicine. Recent developments in chemical analysis have revealed that fluorinated compounds have become ubiquitously spread and are regarded as a potential threats to the environment. Due to the carbon-fluorine bond, which has a very high bond strength, these chemicals are extremely persistent towards degradation and some PFCs have a potential for bioaccumulation in organisms. Of particular concern has been the developmental toxicity of PFOS and PFOA, which has been manifested in rodent studies as high mortality of prenatally exposed newborn rats and mice within 24 h after delivery. The nervous system appears to be one of the most sensitive targets of environmental contaminants. The serious developmental effects of PFCs have lead to the upcoming of studies that have investigated neurotoxic effects of these substances. In this review the major findings of the neurotoxicity of the main PFCs and their suggested mechanisms of action are presented. The neurotoxic effects are discussed in light of other toxic effects of PFCs to indicate the significance of PFCs as neurotoxicants. The main findings are that PFCs may induce neurobehavioral effects, particularly in developmentally exposed animals. The effects are, however, subtle and inconclusive and are often induced at concentrations where other toxic effects also are expected. Mechanistic studies have shown that PFCs may affect the thyroid system, influence the calcium homeostasis, protein kinase C, synaptic plasticity and cellular differentiation. Compared to other environmental toxicants the human blood levels of PFCs are high and of particular concern is that susceptible groups may be exposed to a cocktail of substances that in combination reach harmful concentrations.

Theoretical investigations of two adamantane derivatives: A combined X-ray, DFT, QTAIM analysis and molecular docking

NASA Astrophysics Data System (ADS)

Al-Wahaibi, Lamya H.; Sujay, Subramaniam; Muthu, Gangadharan Ganesh; El-Emam, Ali A.; Venkataramanan, Natarajan S.; Al-Omary, Fatmah A. M.; Ghabbour, Hazem A.; Percino, Judith; Thamotharan, Subbiah

2018-05-01

A detailed structural analysis of two adamantane derivatives namely, ethyl 2-[(Z)-1-(adamantan-1-yl)-3-(phenyl)isothioureido]acetate I and ethyl 2-[(Z)-1-(adamantan-1-yl)-3-(4-fluorophenyl)isothioureido]acetate II is carried out to understand the effect of fluorine substitution. The introduction of fluorine atom alters the crystal packing and is completely different from its parent compound. The fluorine substitution drastically reduced the intermolecular H⋯H contacts and this reduction is compensated by intermolecular F⋯H and F⋯F contacts. The relative contributions of various intermolecular contacts present in these structures were quantified using Hirshfeld surface analysis. Energetically significant molecular pairs were identified from the crystal structures of these compounds using PIXEL method. The structures of I and II are optimized in gas and solvent phases using the B3LYP-D3/6-311++G(d,p) level of theory. The quantum theory of atoms-in-molecules (QTAIM) analysis was carried out to estimate the strengths of various intermolecular contacts present in these molecular dimers. The results suggest that the Hsbnd H bonding take part in the stabilization of crystal structures. The experimental and theoretical UV-Vis results show the variations in HOMO and LUMO energy levels. In silico docking analysis indicates that both compounds I and II may exhibit inhibitory activity against 11-β-hydroxysteroid dehydrogenase 1 (11-β-HSD1).

Revealing the fine details of functionalized silica surfaces by solid-state NMR and adsorption isotherm measurements: the case of fluorinated stationary phases for liquid chromatography.

PubMed

Ciogli, Alessia; Simone, Patrizia; Villani, Claudio; Gasparrini, Francesco; Laganà, Aldo; Capitani, Donatella; Marchetti, Nicola; Pasti, Luisa; Massi, Alessandro; Cavazzini, Alberto

2014-06-23

The structural and chromatographic characterization of two novel fluorinated mesoporous materials prepared by covalent reaction of 3-(pentafluorophenyl)propyldimethylchlorosilane and perfluorohexylethyltrichlorosilane with 2.5 μm fully porous silica particles is reported. The adsorbents were characterized by solid state (29)Si, (13)C, and (19)F NMR spectroscopy, low-temperature nitrogen adsorption, elemental analysis (C and F), and various chromatographic measurements, including the determination of adsorption isotherms. The structure and abundance of the different organic surface species, as well as the different silanol types, were determined. In particular, the degree of so-called horizontal polymerization, that is, Si-O-Si bridging parallel to the silica surface due to the reaction, under "quasi-dry" conditions, of trifunctional silanizing agents with the silica surface was quantified. Significant agreement was found between the information provided by solid-state NMR, elemental analysis, and excess isotherms regarding the amount of surface residual silanol groups, on the one hand, and the degree of surface functionalization, on the other. Finally, the kinetic performance of the fluorinated materials as separation media for applications in near-ultrahigh-performance liquid chromatography was evaluated. At reduced velocities of about 5.5 (ca. 600 bar backpressure at room temperature) with 3 mm diameter columns and toluene as test compound, reduced plate heights on the order of 2 were obtained on columns of both adsorbents. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Examination of fluorination effect on physical properties of saturated long-chain alcohols by DSC and Langmuir monolayer.

PubMed

Nakahara, Hiromichi; Nakamura, Shohei; Okahashi, Yoshinori; Kitaguchi, Daisuke; Kawabata, Noritake; Sakamoto, Seiichi; Shibata, Osamu

2013-02-01

Partially fluorinated long-chain alcohols have been newly synthesized from a radical reaction, which is followed by a reductive reaction. The fluorinated alcohols have been investigated by differential scanning calorimetry (DSC) and compression isotherms in a Langmuir monolayer state. Their melting points increase with an increase in chain length due to elongation of methylene groups. However, the melting points for the alcohols containing shorter fluorinated moieties are lower than those for the typical hydrogenated fatty alcohols. Using the Langmuir monolayer technique, surface pressure (π)-molecular area (A) and surface potential (ΔV)-A isotherms of monolayers of the fluorinated alcohols have been measured in the temperature range from 281.2 to 303.2K. In addition, a compressibility modulus (Cs(-1)) is calculated from the π-A isotherms. Four kinds of the alcohol monolayers show a phase transition (π(eq)) from a disordered to an ordered state upon lateral compression. The π(eq) values increase linearly with increasing temperatures. A slope of π(eq) against temperature for the alcohols with shorter fluorocarbons is unexpectedly larger than that for the corresponding fatty alcohols. Generally, fluorinated amphiphiles have a greater thermal stability (or resistance), which is a characteristic of highly fluorinated or perfluorinated compounds. Herein, however, the alcohols containing perfluorobutylated and perfluorohexylated chains show the irregular thermal behavior in both the solid and monolayer states. Copyright © 2012 Elsevier B.V. All rights reserved.

Direct synthesis of Z-alkenyl halides through catalytic cross-metathesis

PubMed Central

Koh, Ming Joo; Nguyen, Thach T.; Zhang, Hanmo; Schrock, Richard R.; Hoveyda, Amir H.

2016-01-01

Olefin metathesis has made a significant impact on modern organic chemistry, but important shortcomings remain: for example, the lack of efficient processes that can be used to generate acyclic alkenyl halides. Halo-substituted ruthenium carbene complexes decompose rapidly or deliver low activity and/or minimal stereoselectivity, and our understanding of the corresponding high-oxidation-state systems is very limited. In this manuscript, we show that previously unknown halo-substituted molybdenum alkylidene species are exceptionally reactive and are able to participate in high-yielding olefin metathesis reactions that afford acyclic 1,2-disubstituted Z-alkenyl halides. Transformations are promoted by small amounts of an in situ-generated catalyst with unpurified, commercially available and easy-to-handle liquid 1,2-dihaloethene reagents and proceed to high conversion at ambient temperature within four hours. Many alkenyl chlorides, bromides and fluorides can be obtained in up to 91 percent yield and complete Z selectivity. This method can be used to easily synthesize biologically active compounds and to perform the site- and stereoselective fluorination of other organic compounds. PMID:27008965

Electron-Impact Total Ionization Cross Sections of Fluorine Compounds

NASA Astrophysics Data System (ADS)

Kim, Y.-K.; Ali, M. A.; Rudd, M. E.

1997-10-01

A theoretical method called the Binary-Encounter-Bethe (BEB) model(M. A. Ali, Y.-K. Kim, H. Hwang, N. M. Weinberger, and M. E. Rudd, J. Chem. Phys. 106), 9602 (1997), and references therein. that combines the Mott cross section at low incident energies T and the Bethe cross section at high T was applied to fluorine compounds of interest to plasma processing of semiconductors (CF_4, CHF_3, C_2F_6, C_4F_8, etc.). The theory provides total ioniztion cross sections in an analytic form from the threshold to a few keV in T, making it convenient to use the theory for modeling. The theory is particularly effective for closed-shell molecules. The theoretical cross sections are compared to available experimental data.

Fissile interrogation using gamma rays from oxygen

DOEpatents

Smith, Donald; Micklich, Bradley J.; Fessler, Andreas

2004-04-20

The subject apparatus provides a means to identify the presence of fissionable material or other nuclear material contained within an item to be tested. The system employs a portable accelerator to accelerate and direct protons to a fluorine-compound target. The interaction of the protons with the fluorine-compound target produces gamma rays which are directed at the item to be tested. If the item to be tested contains either a fissionable material or other nuclear material the interaction of the gamma rays with the material contained within the test item with result in the production of neutrons. A system of neutron detectors is positioned to intercept any neutrons generated by the test item. The results from the neutron detectors are analyzed to determine the presence of a fissionable material or other nuclear material.

Aromatic fluorine compounds. X. The 2,3- and 2,6-difluoropyridines

USGS Publications Warehouse

Finger, G.C.; Starr, L.D.; Roe, A.; Link, W.J.

1962-01-01

The preparation of difluoropyridines by the Schiemann reaction was investigated. 2-Amino-6-fluoropyridine (IIIa), necessary for the synthesis of 2,6-difluoropyridine (IVa) by the Schiemann reaction, was conveniently prepared by the Curtius degradation of 6-fluoropicolinic hydrazide (IIa) and by the Hofmann reaction on 6-fluoropicolinamide (IId). Since an ??-fluorine on a pyridine nucleus is preferentially replaced by hydrazine when it is either adjacent to or opposite a carbomethoxy group, the hydrazides necessary for the synthesis of 3-amino-2- and 6-fluoropyridine could not be prepared. These amines were prepared from the appropriate 2-fluoropyridinecarboxamide by the Hofmann reaction. The preparation of difluoropyridines was successful with two of the aminofluoropyridines and led to the following new compounds: 2,3-difluoro(IVb) and 2,6-difluoropyridine (IVa).

Electrochemical fluorination of La(2)CuO(4): a mild "chimie douce" route to superconducting oxyfluoride materials.

PubMed

Delville, M H; Barbut, D; Wattiaux, A; Bassat, J M; Ménétrier, M; Labrugère, C; Grenier, J C; Etourneau, J

2009-08-17

The fluorination of La(2)CuO(4) was achieved for the first time under normal conditions of pressure and temperature (1 MPa and 298 K) via electrochemical insertion in organic fluorinated electrolytes and led to lanthanum oxyfluorides of general formula La(2)CuO(4)F(x). Analyses showed that, underneath a very thin layer of LaF(3) (a few atomic layers), fluorine is effectively inserted in the material's structure. The fluorination strongly modifies the lanthanum environment, whereas very little modification is observed on copper, suggesting an insertion in the La(2)O(2) blocks of the structure. In all cases, fluorine insertion breaks the translation symmetry and introduces a long-distance disorder, as shown by electron spin resonance. These results highlight the efficiency of electrochemistry as a new "chimie douce" type fluorination technique for solid-state materials. Performed at room temperature, it additionally does not require any specific experimental care. The choice of the electrolytic medium is crucial with regard to the fluorine insertion rate as well as the material deterioration. Successful application of this technique to the well-known La(2)CuO(4) material provides a basis for further syntheses from other oxides.

Fluorination of Metal Phthalocyanines: Single-Crystal Growth, Efficient N-Channel Organic Field-Effect Transistors, and Structure-Property Relationships

PubMed Central

Jiang, Hui; Ye, Jun; Hu, Peng; Wei, Fengxia; Du, Kezhao; Wang, Ning; Ba, Te; Feng, Shuanglong; Kloc, Christian

2014-01-01

The fluorination of p-type metal phthalocyanines produces n-type semiconductors, allowing the design of organic electronic circuits that contain inexpensive heterojunctions made from chemically and thermally stable p- and n-type organic semiconductors. For the evaluation of close to intrinsic transport properties, high-quality centimeter-sized single crystals of F16CuPc, F16CoPc and F16ZnPc have been grown. New crystal structures of F16CuPc, F16CoPc and F16ZnPc have been determined. Organic single-crystal field-effect transistors have been fabricated to study the effects of the central metal atom on their charge transport properties. The F16ZnPc has the highest electron mobility (~1.1 cm2 V−1 s−1). Theoretical calculations indicate that the crystal structure and electronic structure of the central metal atom determine the transport properties of fluorinated metal phthalocyanines. PMID:25524460

Interest of fluorine-19 nuclear magnetic resonance spectroscopy in the detection, identification and quantification of metabolites of anticancer and antifungal fluoropyrimidine drugs in human biofluids.

PubMed

Martino, Robert; Gilard, Véronique; Desmoulin, Franck; Malet-Martino, Myriam

2006-01-01

The metabolism of fluorouracil and fluorocytosine, two 5-fluoropyrimidine drugs in clinical use, was investigated. (19)F nuclear magnetic resonance (NMR) spectroscopy was used as an analytical technique for the detection, identification and quantification of fluorinated metabolites of these drugs in intact human biofluids as well as fluorinated degradation compounds of fluorouracil in commercial vials. (19)F NMR provides a highly specific tool for the detection and absolute quantification, in a single run, of all the fluorinated species, including unexpected substances, present in biofluids of patients treated with fluorouracil or fluorocytosine. Besides the parent drug and the already known fluorinated metabolites, nine new metabolites were identified for the first time with (19)F NMR in human biofluids. Six of them can only be observed with this technique: fluoride ion, N-carboxy-alpha-fluoro-beta-alanine, alpha-fluoro-beta-alanine conjugate with deoxycholic acid, 2-fluoro-3-hydroxypropanoic acid, fluoroacetic acid, O(2)-beta-glucuronide of fluorocytosine. (19)F NMR studies of biological fluids of patients treated with anticancer fluorouracil or antifungal fluorocytosine have furthered the understanding of their catabolic pathways.

Fluorination of phthalocyanine substituents: Improved photoproperties and enhanced photodynamic efficacy after optimal micellar formulations.

PubMed

Pucelik, Barbara; Gürol, Ilke; Ahsen, Vefa; Dumoulin, Fabienne; Dąbrowski, Janusz M

2016-11-29

A fluorinated phthalocyanine and its non-fluorinated analogue were selected to evaluate the potential enhancement of fluorination on photophysical, photochemical and redox properties as well as on biological activity in cellular and animal models. Due to the pharmacological relevance, the affinity of these phthalocyanines towards biological membranes (logP ow ) as well as their primary interaction with human serum albumin (HSA) or low-density lipoprotein (LDL) were determined. Water-dispersible drug formulation of phthalocyanines via Pluronic ® -based triblock copolymer micelles was prepared to avoid self-aggregation effects and to improve their delivery. The obtained results demonstrate that phthalocyanines incorporation into tunable-polymeric micelles significantly enhanced their cellular uptake and their photocytotoxicity. The improved biodistribution and photodynamic efficacy of the phthalocyanines-triblock copolymer conjugates was also confirmed in vivo in CT26 bearing BALB/c mice. PDT with both compounds led to tumor growth inhibition in all treated animals. Fluorinated phthalocyanine 2 turned out to be the most effective anticancer agent as the tumors of 20% of mice treated regressed completely and did not appear for over one year after treatment. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Synthesis of fluorinated graphene oxide by using an easy one-pot deoxyfluorination reaction.

PubMed

Aguilar-Bolados, Héctor; Contreras-Cid, Ahirton; Yazdani-Pedram, Mehrdad; Acosta-Villavicencio, Gabriela; Flores, Marcos; Fuentealba, Pablo; Neira-Carrillo, Andrónico; Verdejo, Raquel; López-Manchado, Miguel A

2018-08-15

The fluorination of two types of graphene oxides conducted by an easy and scalable deoxyfluorination reaction is reported. This reaction was carried out using diethylaminodifluorosulfinium tetrafluoroborate, a stable compound and an efficient reagent for replacing oxygenated functional groups of graphene oxide by fluoride. The graphene oxide produced by the Hummers' method (GOH) showed lower reactivity than that produced by the Brodie's method (GOB). X-ray photoelectron spectroscopy indicated that the highest fluorination degree achieved was 4.7 at.% when GOB was used, and the CF character corresponds to semi-ionic bonds. Additionally, a partial reduction of GO was concomitant with the functionalization reaction. The deoxyfluorination reaction changed the crystalline structure of GO, favoring the reconstruction of Csp 2 structure of the graphene lattice and reducing the number of stacked layers. The fluorination led to the modification of the electronic band structure of this material, increasing the band gap from 2.05 eV for GOB to 3.88 eV for fluorinated GOB, while for GOH the low flurionation led to a slight increase of the band gap, from 3.48 eV to 3.57 eV. Copyright © 2018 Elsevier Inc. All rights reserved.

Prediction of the air-water partition coefficient for perfluoro-2-methyl-3-pentanone using high-level Gaussian-4 composite theoretical methods.

PubMed

Rayne, Sierra; Forest, Kaya

2014-09-19

The air-water partition coefficient (Kaw) of perfluoro-2-methyl-3-pentanone (PFMP) was estimated using the G4MP2/G4 levels of theory and the SMD solvation model. A suite of 31 fluorinated compounds was employed to calibrate the theoretical method. Excellent agreement between experimental and directly calculated Kaw values was obtained for the calibration compounds. The PCM solvation model was found to yield unsatisfactory Kaw estimates for fluorinated compounds at both levels of theory. The HENRYWIN Kaw estimation program also exhibited poor Kaw prediction performance on the training set. Based on the resulting regression equation for the calibration compounds, the G4MP2-SMD method constrained the estimated Kaw of PFMP to the range 5-8 × 10(-6) M atm(-1). The magnitude of this Kaw range indicates almost all PFMP released into the atmosphere or near the land-atmosphere interface will reside in the gas phase, with only minor quantities dissolved in the aqueous phase as the parent compound and/or its hydrate/hydrate conjugate base. Following discharge into aqueous systems not at equilibrium with the atmosphere, significant quantities of PFMP will be present as the dissolved parent compound and/or its hydrate/hydrate conjugate base.

Discovery of chiral dihydropyridopyrimidinones as potent, selective and orally bioavailable inhibitors of AKT.

PubMed

Parthasarathy, Saravanan; Henry, Kenneth; Pei, Huaxing; Clayton, Josh; Rempala, Mark; Johns, Deidre; De Frutos, Oscar; Garcia, Pablo; Mateos, Carlos; Pleite, Sehila; Wang, Yong; Stout, Stephanie; Condon, Bradley; Ashok, Sheela; Lu, Zhohai; Ehlhardt, William; Raub, Tom; Lai, Mei; Geeganage, Sandaruwan; Burkholder, Timothy P

2018-06-01

During the course of our research efforts to develop potent and selective AKT inhibitors, we discovered enatiomerically pure substituted dihydropyridopyrimidinones (DHP) as potent inhibitors of protein kinase B/AKT with excellent selectivity against ROCK 2 . A key challenge in this program was the poor physicochemical properties of the initial lead compound 5. Integration of structure-based drug design and physical properties-based design resulted in replacement of a highly hydrophobic poly fluorinated aryl ring by a simple trifluoromethyl that led to identification of compound 6 with much improved physicochemical properties. Subsequent SAR studies led to the synthesis of new pyran analog 7 with improved cell potency. Further optimization of pharmacokintetics properties by increasing permeability with appropriate fluorinated alkyl led to compound 8 as a potent, selective AKT inhibitors that blocks the phosphorylation of GSK3β in vivo and had robust, dose and concentration dependent efficacy in the U87MG tumor xenograft model. Copyright © 2018 Elsevier Ltd. All rights reserved.

Efficient Syntheses of Novel Fluoro-Substituted Pentacenes and Azapentacenes: Molecular and Solid-State Properties.

PubMed

Schwaben, Jonas; Münster, Niels; Klues, Michael; Breuer, Tobias; Hofmann, Philipp; Harms, Klaus; Witte, Gregor; Koert, Ulrich

2015-09-21

Non-symmetrical 6,13-disubstituted pentacenes bearing trifluoromethyl and aryl substituents have been synthesized starting from pentacenequinone. Diazapentacenes with a variety of fluorine substituents were prepared either via a Hartwig-Buchwald aryl amination route or by a SNAr strategy. As a result of a non-symmetric substitution pattern containing electron-donating substituents in combination with electron-accepting fluorine substituents, the synthesized compounds feature distinct molecular dipoles. All compounds are analyzed regarding their optoelectronic properties in solution with special focus on the frontier orbital energies as well as their molecular packing in the crystal structures. The analyses of isolated molecules are complemented by thin-film studies to examine their solid-state properties. A precise comparison between these and the molecular properties gave detailed insights into the exciton binding energies of these compounds, which are explained by means of a simple model considering the molecular packing and polarizabilities. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Natural Organohalogens: A New Frontier for Medicinal Agents?

NASA Astrophysics Data System (ADS)

Gribble, Gordon W.

2004-10-01

More than 4000 naturally occurring organohalogen compounds are known. These include a relatively small number of abiogenic organohalogens from volcanoes, forest fires, geothermal processes, and meteorites, and a very large number of biogenic organohalogens produced by myriad living organisms as part of their chemical makeup that serve as hormones, pheromones, repellents, and natural pesticides. From the chemically simple methyl chloride, methyl bromide, and chloroform to the structurally complex vancomycin, pyrroindomycin, and bastadins, the diversity of these organohalogens is unsurpassed among natural products. Most natural organohalogens contain chlorine (2300) or bromine (2100), but a significant number contain iodine (120) or fluorine (30). Several hundred marine natural products contain both chlorine and bromine. The present article focuses on newly discovered biogenic organohalogens, with an emphasis on those biologically active examples from marine organisms, bacteria, terrestrial plants, and higher life forms including humans.

ODS Destruction in the United States and Abroad - February 2018

EPA Pesticide Factsheets

This technical report provides information on sources, destruction technologies, and best practices for recovery, collection, transport, and destruction of ozone-depleting substances and other fluorinated compounds such as HFCs

A new thermally immobilized fluorinated stationary phase for RP-HPLC.

PubMed

Maldaner, Liane; Jardim, Isabel C S F

2010-02-01

A new fluorinated stationary phase was prepared through thermal immobilization of poly(methyl-3,3,3-trifluoropropylsiloxane) onto 5 microm Kromasil silica particles. The best conditions of immobilization time and temperature were determined through a central composite design and response surface methodologies. Physical-chemical characterization using solid-state (29)Si NMR measurements, infrared spectroscopy and elemental analysis showed that the immobilization process was effective to promote a coating of the support that corresponds to a monolayer of polymer. The stationary phase presents selectivity for positional isomers and good peak shape for basic compounds.

Synthesis of a Series of Caffeic Acid Phenethyl Amide (CAPA) Fluorinated Derivatives: Comparison of Cytoprotective Effects to Caffeic Acid Phenethyl Ester (CAPE)

DTIC Science & Technology

2010-06-11

the cinnamic acid phenyl ring. Although compound 4c proved to be very cytotoxic in HUVEC over a 24 h period, the toxicity is less apparent over a 5 h...drug development process, as it determines how much of the initial dose actually reaches the target site. Cinnamic acid -derived amides are known to...Synthesis of a series of caffeic acid phenethyl amide (CAPA) fluorinated derivatives: Comparison of cytoprotective effects to caffeic acid phenethyl

Exchange Reactions of Organotin and Organosilicon Compounds with Mild Fluorinating Agents

DTIC Science & Technology

1992-03-01

methylphosphonic difluoride, boron trifluoride etherate, and perfluoroisobutene all react with both organosilicon and organotin. alkoxides to give...inlet tube, was charged with tributyltin cyanide (53.30 gm, 0.1686 mol) in a dry glove bag under an inert atmosphere and 500 ml of dry xylene was then...Chem. Vol. 29, p 471 (1985). 6. Tyuleneva, V.V., Rozov, L.A., Zeifman, Yu.V. and I. L. Knuny- ants,"Exchange of Fluorine by Chlorine in Perfluoro-isobutene," Tzv.Akad.Nauk. SSSR. Ser. Khim No. 5, p 1136 (1975). 17

Viscosity of the saturated liquid phase of three fluorinated ethanes: R152a, R143a, and R125

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ripple, D.; Defibaugh, D.

1997-03-01

Data are reported for the viscosity of three saturated liquids over a temperature range from 255 K to 323 K. The liquids studied are the fluorinated compounds 1,1-difluoroethane (R152a), 1,1,1-trifluoroethane (R143a), and pentafluoroethane (R125). A capillary viscometer constructed of stainless steel and sapphire was used to obtain the data. The viscosity measurements have an expanded uncertainty of 2.4%. A free volume model of viscosity was used to correlate the data.

Electrochemical fluorination for processing of used nuclear fuel

DOEpatents

Garcia-Diaz, Brenda L.; Martinez-Rodriguez, Michael J.; Gray, Joshua R.; Olson, Luke C.

2016-07-05

A galvanic cell and methods of using the galvanic cell is described for the recovery of uranium from used nuclear fuel according to an electrofluorination process. The galvanic cell requires no input energy and can utilize relatively benign gaseous fluorinating agents. Uranium can be recovered from used nuclear fuel in the form of gaseous uranium compound such as uranium hexafluoride, which can then be converted to metallic uranium or UO.sub.2 and processed according to known methodology to form a useful product, e.g., fuel pellets for use in a commercial energy production system.

Assessment of arsenic and fluorine in surface soil to determine environmental and health risk factors in the Comarca Lagunera, Mexico.

PubMed

Sariñana-Ruiz, Yareli A; Vazquez-Arenas, Jorge; Sosa-Rodríguez, Fabiola S; Labastida, Israel; Armienta, Ma Aurora; Aragón-Piña, Antonio; Escobedo-Bretado, Miguel A; González-Valdez, Laura S; Ponce-Peña, Patricia; Ramírez-Aldaba, Hugo; Lara, René H

2017-07-01

Total, bioaccessible and mobile concentrations of arsenic and fluorine are determined in polluted surface soil within the Comarca Lagunera region using standardized protocols to obtain a full description of the environmental behavior for these elements. The composition of mineral phases associated with them is evaluated with microscopic and spectroscopic techniques. Mineralogical characterizations indicate that ultra-fine particles (<1-5 μm) including mimetite-vanadite (Pb 5 (AsO 4 ) 3 Cl, Pb 5 (AsO 4 , VO 4 ) 3 Cl)-like, lead arseniate (Pb 3 (AsO 4 ) 2 )-like and complex arsenic-bearing compounds are main arsenic-bearing phases, while fluorite (CaF 2 ) is the only fluorine-bearing phase. Total fluorine and arsenic concentrations in surface soil range from 89.75 to 926.63 and 2.7-78.6 mg kg -1 , respectively, exceeding in many points a typical baseline value for fluorine (321 mg kg -1 ), and trigger level criterion for arsenic soil remediation (20 mg kg -1 ); whereas fluoride and arsenic concentrations in groundwater vary from 0.24 to 1.8 mg L -1 and 0.12-0.650 mg L -1 , respectively. The main bioaccessible percentages of soil in the gastric phase (SBRC-G) are estimated for arsenic from 1 to 63%, and this parameter in the intestinal phase (SBRC-I) fluorine from 2 to 46%, suggesting human health risks for this region. While a negligible/low mobility is found in soil for arsenic (0.1-11%), an important mobility is determined for fluorine (2-39%), indicating environmental risk related to potential fluorine release. The environmental and health risks connected to arsenic and fluorine are discussed based on experimental data. Copyright © 2017 Elsevier Ltd. All rights reserved.

40 CFR 180.145 - Fluorine compounds; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., postharvest 15.0 Barley, pearled barley, postharvest 45.0 Cattle, meat, dried 40 Cheese 5.0 Cacao bean, roasted bean, postharvest 20 Coconut, postharvest 40 Coffee, bean, green, postharvest 15 Corn, field...

40 CFR 180.145 - Fluorine compounds; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., postharvest 15.0 Barley, pearled barley, postharvest 45.0 Cattle, meat, dried 40 Cheese 5.0 Cacao bean, roasted bean, postharvest 20 Coconut, postharvest 40 Coffee, bean, green, postharvest 15 Corn, field...

40 CFR 180.145 - Fluorine compounds; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., postharvest 15.0 Barley, pearled barley, postharvest 45.0 Cattle, meat, dried 40 Cheese 5.0 Cacao bean, roasted bean, postharvest 20 Coconut, postharvest 40 Coffee, bean, green, postharvest 15 Corn, field...

40 CFR 180.145 - Fluorine compounds; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., postharvest 15.0 Barley, pearled barley, postharvest 45.0 Cattle, meat, dried 40 Cheese 5.0 Cacao bean, roasted bean, postharvest 20 Coconut, postharvest 40 Coffee, bean, green, postharvest 15 Corn, field...

40 CFR 180.145 - Fluorine compounds; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., postharvest 15.0 Barley, pearled barley, postharvest 45.0 Cattle, meat, dried 40 Cheese 5.0 Cacao bean, roasted bean, postharvest 20 Coconut, postharvest 40 Coffee, bean, green, postharvest 15 Corn, field...

Enhanced corrosion resistance and hemocompatibility of biomedical NiTi alloy by atmospheric-pressure plasma polymerized fluorine-rich coating

NASA Astrophysics Data System (ADS)

Li, Penghui; Li, Limin; Wang, Wenhao; Jin, Weihong; Liu, Xiangmei; Yeung, Kelvin W. K.; Chu, Paul K.

2014-04-01

To improve the corrosion resistance and hemocompatibility of biomedical NiTi alloy, hydrophobic polymer coatings are deposited by plasma polymerization in the presence of a fluorine-containing precursor using an atmospheric-pressure plasma jet. This process takes place at a low temperature in air and can be used to deposit fluoropolymer films using organic compounds that cannot be achieved by conventional polymerization techniques. The composition and chemical states of the polymer coatings are characterized by fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The corrosion behavior of the coated and bare NiTi samples is assessed and compared by polarization tests and electrochemical impedance spectroscopy (EIS) in physiological solutions including simulated body fluids (SBF) and Dulbecco's Modified Eagle's medium (DMEM). The corrosion resistance of the coated NiTi alloy is evidently improved. Protein adsorption and platelet adhesion tests reveal that the adsorption ratio of albumin to fibrinogen is increased and the number of adherent platelets on the coating is greatly reduced. The plasma polymerized coating renders NiTi better in vitro hemocompatibility and is promising as a protective and hemocompatible coating on cardiovascular implants.

Negative-ion atmospheric pressure ionisation of semi-volatile fluorinated compounds for ultra-high-performance liquid chromatography tandem mass spectrometry analysis.

PubMed

Ayala-Cabrera, Juan F; Javier Santos, F; Moyano, Encarnación

2018-05-24

In this work, the feasibility of negative-ion atmospheric pressure chemical ionisation (APCI) and atmospheric pressure photoionisation (APPI) for ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) determination of fluorotelomer alcohols (FTOHs), fluorinated octanesulfonamides (FOSAs) and fluorinated octanesulfonamido-ethanols (FOSEs) was evaluated. The study of the effect of mobile phase composition on the atmospheric pressure ionisation of these compounds indicated that methanol/water mixtures provided the best responses in APCI, while acetonitrile/water with a post-column addition of toluene as dopant was the most appropriated mixture in APPI. Under the optimal working conditions, most of the target compounds produced the ion [M-H] - as base peak, although in-source collision-induced dissociation fragment ions in APCI and APPI and superoxide adduct ions [M+O 2 ] -• in APPI were also present. These ions proved to be more useful as precursor ions for MS/MS determination than the adduct ions generated in electrospray. Although the UHPLC-APCI-MS/MS method allowed the determination of these semi-volatile compounds at low concentration levels, the analysis by UHPLC-APPI-MS/MS provided the lowest limits of detection and it was applied to the analysis of water samples in combination with solid-phase extraction. Quality parameters demonstrated the good performance of the proposed method, providing low method limits of detection (0.3-6 ng L -1 ), good precision (RSD % < 5%) and an accurate quantification (relative error % < 14%). Among the river water samples analysed by the developed method, 4:2 FTOH and N-EtFOSA were determined at 30 and 780 ng L -1 , respectively.

Comparing blends and blocks: Synthesis of partially fluorinated diblock polythiophene copolymers to investigate the thermal stability of optical and morphological properties

PubMed Central

Boufflet, Pierre; Wood, Sebastian; Wade, Jessica; Fei, Zhuping; Kim, Ji-Seon

2016-01-01

Summary The microstructure of the active blend layer has been shown to be a critically important factor in the performance of organic solar devices. Block copolymers provide a potentially interesting avenue for controlling this active layer microstructure in solar cell blends. Here we explore the impact of backbone fluorination in block copolymers of poly(3-octyl-4-fluorothiophene)s and poly(3-octylthiophene) (F-P3OT-b-P3OT). Two block co-polymers with varying block lengths were prepared via sequential monomer addition under Kumada catalyst transfer polymerisation (KCTP) conditions. We compare the behavior of the block copolymer to that of the corresponding homopolymer blends. In both types of system, we find the fluorinated segments tend to dominate the UV–visible absorption and molecular vibrational spectral features, as well as the thermal behavior. In the block copolymer case, non-fluorinated segments appear to slightly frustrate the aggregation of the more fluorinated block. However, in situ temperature dependent Raman spectroscopy shows that the intramolecular order is more thermally stable in the block copolymer than in the corresponding blend, suggesting that such materials may be interesting for enhanced thermal stability of organic photovoltaic active layers based on similar systems. PMID:27829922

Synthesis of carbon-11, fluorine-18, and nitrogen-13 labeled radiotracers for biomedical applications. Nuclear Science Series: Nuclear Medicine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fowler, J.S.; Wolf, A.P.

1982-09-01

Carbon 11, Fluorine 18, and Nitrogen 13-labeled radiotracers are reviewed from the standpoint of synthetic organic chemistry while keeping in perspective the necessity of integrating the organic chemistry with the design and ultimate application of the radiotracer. The reactions used, the principles used to adapt these reactions to labeling with short-lived radionuclides, and the concepts of chemical reactivity form the framework upon which synthetic strategies for short-lived radiotracers are developed. Potentially new routes are suggested which may be applied to problems in labeling organic molecules. (ACR)

Pyrene-Tagged Ionic Liquids: Separable Organic Catalysts for SN2 Fluorination.

PubMed

Taher, Abu; Lee, Kyo Chul; Han, Hye Ji; Kim, Dong Wook

2017-07-07

We prepared pyrene-substituted imidazolium-based ionic liquids (PILs) as organic catalysts for the S N 2 fluorination using alkali metal fluoride (MF). In this system, the PIL significantly enhanced the reactivity of MF due to the phase-transfer catalytic effect of the imidazolium moiety as well as the metal cation-π (pyrene) interactions. Furthermore, this homogeneous catalyst PIL was easily separated from the reaction mixture using reduced graphene oxide by π-π stacking with the pyrene of PIL.

The origin of excellent gate-bias stress stability in organic field-effect transistors employing fluorinated-polymer gate dielectrics.

PubMed

Kim, Jiye; Jang, Jaeyoung; Kim, Kyunghun; Kim, Haekyoung; Kim, Se Hyun; Park, Chan Eon

2014-11-12

Tuning of the energetic barriers to charge transfer at the semiconductor/dielectric interface in organic field-effect transistors (OFETs) is achieved by varying the dielectric functionality. Based on this, the correlation between the magnitude of the energy barrier and the gate-bias stress stability of the OFETs is demonstrated, and the origin of the excellent device stability of OFETs employing fluorinated dielectrics is revealed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

New synthesis of fluorine-18-labeled 6-fluoro-L-dopa by cleaving the carbon-silicon bond with fluorine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diksic, M.; Farrokhzad, S.

A new synthesis of 3,4-dihydroxy-6-( YF)fluoro-L-phenylalanine using 6-trimethylsilyl-3,4-dimethoxy-L-dopa-ethylester as a fluorination substrate is described. The silane is prepared from the corresponding bromo compound by reacting the latter with magnesium and trimethylsilyl chloride. Reaction of the silane with ( YF)F2 in a mixture of freon-11/CCl4 (1:1) kept in a dry ice bath, subsequent hydrolysis with concentrated HBr in a bath at 140 degrees C, and simple chromatographic purification yielded YF-labeled 6-fluoro-L-dopa. A radiochemical yield of about 8% was achieved at the end of the 1-hr synthesis. The specific activity at the end of the synthesis was about 680 mCi/mmol after amore » 30-min irradiation.« less

Health impacts of domestic coal use in China

USGS Publications Warehouse

Finkelman, R.B.; Belkin, H.E.; Zheng, B.

1999-01-01

Domestic coal combustion has had profound adverse effects on the health of millions of people worldwide. In China alone several hundred million people commonly burn raw coal in unvented stoves that permeate their homes with high levels of toxic metals and organic compounds. At least 3,000 people in Guizhou Province in southwest China are suffering from severe arsenic poisoning. The primary source of the arsenic appears to be consumption of chili peppers dried over fires fueled with high-arsenic coal. Coal samples in the region were found to contain up to 35,000 ppm arsenic. Chili peppers dried over high-arsenic coal fires adsorb 500 ppm arsenic on average. More than 10 million people in Guizhou Province and surrounding areas suffer from dental and skeletal fluorosis. The excess fluorine is caused by eating corn dried over burning briquettes made from high-fluorine coals and high-fluorine clay binders. Polycyclic aromatic hydrocarbons formed during coal combustion are believed to cause or contribute to the high incidence of esophageal and lung cancers in parts of China. Domestic coal combustion also has caused selenium poisoning and possibly mercury poisoning. Better knowledge of coal quality parameters may help to reduce some of these health problems. For example, information on concentrations and distributions of potentially toxic elements in coal may help delineate areas of a coal deposit to be avoided. Information on the modes of occurrence of these elements and the textural relations of the minerals and macerals in coal may help predict the behavior of the potentially toxic components during coal combustion.

The vicinal difluoro motif: The synthesis and conformation of erythro- and threo- diastereoisomers of 1,2-difluorodiphenylethanes, 2,3-difluorosuccinic acids and their derivatives

PubMed Central

O'Hagan, David; Rzepa, Henry S; Schüler, Martin; Slawin, Alexandra MZ

2006-01-01

Background It is well established that vicinal fluorines (RCHF-CHFR) prefer to adopt a gauche rather than an anti conformation when placed along aliphatic chains. This has been particularly recognised for 1,2-difluoroethane and extends to 2,3-difluorobutane and longer alkyl chains. It follows in these latter cases that if erythro and threo vicinal difluorinated stereoisomers are compared, they will adopt different overall conformations if the fluorines prefer to be gauche in each case. This concept is explored in this paper with erythro- and threo- diastereoisomers of 2,3-difluorosuccinates. Results A synthetic route to 2,3-difluorosuccinates has been developed through erythro- and threo- 1,2-difluoro-1,2-diphenylethane which involved the oxidation of the aryl rings to generate the corresponding 2,3-difluorosuccinic acids. Ester and amide derivatives of the erythro- and threo- 2,3-difluorosuccinic acids were then prepared. The solid and solution state conformation of these compounds was assessed by X-ray crystallography and NMR. Ab initio calculations were also carried out to model the conformation of erythro- and threo- 1,2-difluoro-1,2-diphenylethane as these differed from the 2,3-difluorosuccinates. Conclusion In general the overall chain conformations of the 2,3-difluorosuccinates diastereoisomers were found to be influenced by the fluorine gauche effect. The study highlights the prospects of utilising the vicinal difluorine motif (RCHF-CHFR) as a tool for influencing the conformation of performance organic molecules and particularly tuning conformation by selecting specific diastereoisomers (erythro or threo). PMID:17014729

The vicinal difluoro motif: The synthesis and conformation of erythro- and threo- diastereoisomers of 1,2-difluorodiphenylethanes, 2,3-difluorosuccinic acids and their derivatives.

PubMed

O'Hagan, David; Rzepa, Henry S; Schüler, Martin; Slawin, Alexandra M Z

2006-10-02

It is well established that vicinal fluorines (RCHF-CHFR) prefer to adopt a gauche rather than an anti conformation when placed along aliphatic chains. This has been particularly recognised for 1,2-difluoroethane and extends to 2,3-difluorobutane and longer alkyl chains. It follows in these latter cases that if erythro and threo vicinal difluorinated stereoisomers are compared, they will adopt different overall conformations if the fluorines prefer to be gauche in each case. This concept is explored in this paper with erythro- and threo- diastereoisomers of 2,3-difluorosuccinates. A synthetic route to 2,3-difluorosuccinates has been developed through erythro- and threo- 1,2-difluoro-1,2-diphenylethane which involved the oxidation of the aryl rings to generate the corresponding 2,3-difluorosuccinic acids. Ester and amide derivatives of the erythro- and threo- 2,3-difluorosuccinic acids were then prepared. The solid and solution state conformation of these compounds was assessed by X-ray crystallography and NMR. Ab initio calculations were also carried out to model the conformation of erythro- and threo- 1,2-difluoro-1,2-diphenylethane as these differed from the 2,3-difluorosuccinates. In general the overall chain conformations of the 2,3-difluorosuccinates diastereoisomers were found to be influenced by the fluorine gauche effect. The study highlights the prospects of utilising the vicinal difluorine motif (RCHF-CHFR) as a tool for influencing the conformation of performance organic molecules and particularly tuning conformation by selecting specific diastereoisomers (erythro or threo).

Health impacts of domestic coal use in China

PubMed Central

Finkelman, Robert B.; Belkin, Harvey E.; Zheng, Baoshan

1999-01-01

Domestic coal combustion has had profound adverse effects on the health of millions of people worldwide. In China alone several hundred million people commonly burn raw coal in unvented stoves that permeate their homes with high levels of toxic metals and organic compounds. At least 3,000 people in Guizhou Province in southwest China are suffering from severe arsenic poisoning. The primary source of the arsenic appears to be consumption of chili peppers dried over fires fueled with high-arsenic coal. Coal samples in the region were found to contain up to 35,000 ppm arsenic. Chili peppers dried over high-arsenic coal fires adsorb 500 ppm arsenic on average. More than 10 million people in Guizhou Province and surrounding areas suffer from dental and skeletal fluorosis. The excess fluorine is caused by eating corn dried over burning briquettes made from high-fluorine coals and high-fluorine clay binders. Polycyclic aromatic hydrocarbons formed during coal combustion are believed to cause or contribute to the high incidence of esophageal and lung cancers in parts of China. Domestic coal combustion also has caused selenium poisoning and possibly mercury poisoning. Better knowledge of coal quality parameters may help to reduce some of these health problems. For example, information on concentrations and distributions of potentially toxic elements in coal may help delineate areas of a coal deposit to be avoided. Information on the modes of occurrence of these elements and the textural relations of the minerals and macerals in coal may help predict the behavior of the potentially toxic components during coal combustion. PMID:10097053

Oxygen anion (O- ) and hydroxide anion (HO- ) reactivity with a series of old and new refrigerants.

PubMed

Le Vot, Clotilde; Lemaire, Joël; Pernot, Pascal; Heninger, Michel; Mestdagh, Hélène; Louarn, Essyllt

2018-04-01

The reactivity of a series of commonly used halogenated compounds (trihalomethanes, chlorofluorocarbon, hydrochlorofluorocarbon, fluorocarbons, and hydrofluoroolefin) with hydroxide and oxygen anion is studied in a compact Fourier transform ion cyclotron resonance. O - is formed by dissociative electron attachment to N 2 O and HO - by a further ion-molecule reaction with ammonia. Kinetic experiments are performed by increasing duration of introduction of the studied molecule at a constant pressure. Hydroxide anion reactions mainly proceed by proton transfer for all the acidic compounds. However, nucleophilic substitution is observed for chlorinated and brominated compounds. For fluorinated compounds, a specific elimination of a neutral fluorinated alkene is observed in our results in parallel with the proton transfer reaction. Oxygen anion reacts rapidly and extensively with all compounds. Main reaction channels result from nucleophilic substitution, proton transfer, and formal H 2 + transfer. We highlight the importance of transfer processes (atom or ion) in the intermediate ion-neutral complex, explaining part of the observed reactivity and formed ions. In this paper, we present the first reactivity study of anions with HFO 1234yf. Finally, the potential of O - and HO - as chemical ionization reagents for trace analysis is discussed. Copyright © 2017 John Wiley & Sons, Ltd.

Fluorine-19 magnetic resonance imaging probe for the detection of tau pathology in female rTg4510 mice.

PubMed

Yanagisawa, Daijiro; Ibrahim, Nor Faeizah; Taguchi, Hiroyasu; Morikawa, Shigehiro; Kato, Tomoko; Hirao, Koichi; Shirai, Nobuaki; Sogabe, Takayuki; Tooyama, Ikuo

2018-05-01

Aggregation of tau into neurofibrillary tangles (NFTs) is characteristic of tauopathies, including Alzheimer's disease. Recent advances in tau imaging have attracted much attention because of its potential contributions to early diagnosis and monitoring of disease progress. Fluorine-19 magnetic resonance imaging ( 19 F-MRI) may be extremely useful for tau imaging once a high-quality probe has been formulated. In this investigation, a novel fluorine-19-labeling compound has been developed as a probe for tau imaging using 19 F-MRI. This compound is a buta-1,3-diene derivative with a polyethylene glycol side chain bearing a CF 3 group and is known as Shiga-X35. Female rTg4510 mice (a mouse model of tauopathy) and wild-type mice were intravenously injected with Shiga-X35, and magnetic resonance imaging of each mouse's head was conducted in a 7.0-T horizontal-bore magnetic resonance scanner. The 19 F-MRI in rTg4510 mice showed an intense signal in the forebrain region. Analysis of the signal intensity in the forebrain region revealed a significant accumulation of fluorine-19 magnetic resonance signal in the rTg4510 mice compared with the wild-type mice. Histological analysis showed fluorescent signals of Shiga-X35 binding to the NFTs in the brain sections of rTg4510 mice. Data collected as part of this investigation indicate that 19 F-MRI using Shiga-X35 could be a promising tool to evaluate tau pathology in the brain. © 2017 Wiley Periodicals, Inc.

[Fluorine removal efficiency of organic-calcium during coal combustion].

PubMed

Liu, Jing; Liu, Jian-Zhong; Zhou, Jun-Hu; Xiao, Hai-Ping; Cen, Ke-Fa

2006-08-01

Effectiveness of calcium magnesium acetate (CMA) and calcium acetate(CA) as feasible HF capture were studied by means of fixed bed tube furnaces. The effects of temperature, particle diameter and Ca/S molar ratio on the fluorine removal efficiency were studied. By contract with CaCO3 at the same condition, we find that the HF capture effectiveness of those sorbents is superior to CaCO3, especially at high temperature. At 1 000 - 1 100 degrees C, the efficiency of fluorine removal during coal combustion of CMA is 1.68 - 1.74 times as that of CaCO3; the efficiency of fluorine removal during coal combustion of CA is 1.28 - 1.37 times as that of CaCO3.

Novel Developments in Organonitrogen Fluorine Chemistry from Carbon- Nitrogen

DTIC Science & Technology

1991-11-21

alkan- imines (R.FC-NBr, P.R CF3. C2 F5, n-C3F7, CF2CI. CCI3). Photolyuis of the perfluorinated N-bromo compounds af- fords the novel perfluoroazines...physical properties. Alternative and improved I syntheses of three compounds are also reported. The perfluorinated N-haloimines, CF 2-NX (X = F, Cl...ihenakaif e anibokn i ls eatv ncephl ndncepii sbTitutionths reactions ead toetdsrutrso a variety of novelrgni compounds . Ofseilitrsoaftedaiiie

Direct experimental observation of mesoscopic fluorous domains in fluorinated room temperature ionic liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lo Celso, F.; Yoshida, Y.; Castiglione, F.

Fluorinated room temperature ionic liquids (FRTILs) represent a class of solvent media that are attracting great attention due to their IL-specific properties as well as features stemming from their fluorous nature. Medium-to-long fluorous tails constitute a well-defined apolar moiety in the otherwise polar environment. Similarly to the case of alkyl tails, such chains are expected to result in the formation of self-assembled fluorous domains. So far, however, no direct experimental observation has been made of the existence of such structural heterogeneities on the nm scale. We report here the first experimental evidence of the existence of mesoscopic spatial segregation ofmore » fluorinated domains, on the basis of highly complementary X-ray and neutron scattering data sets (highlighting the importance of the latter probe) and NMR spectroscopy. Data are interpreted using atomistic molecular dynamics simulations, emphasizing the existence of a self-assembly mechanism that delivers segregated fluorous domains, where preferential solubilisation of fluorinated compounds can occur, thus paving the way for several smart applications.« less

Asymmetric silver-catalysed intermolecular bromotrifluoromethoxylation of alkenes with a new trifluoromethoxylation reagent

NASA Astrophysics Data System (ADS)

Guo, Shuo; Cong, Fei; Guo, Rui; Wang, Liang; Tang, Pingping

2017-06-01

Fluorinated organic compounds are becoming increasingly important in pharmaceuticals, agrochemicals and materials science. The introduction of trifluoromethoxy groups into new drugs and agrochemicals has attracted much attention due to their strongly electron-withdrawing nature and high lipophilicity. However, synthesis of trifluoromethoxylated organic molecules is difficult owing to the decomposition of trifluoromethoxide anion and β-fluoride elimination from transition-metal-trifluoromethoxide complexes, and no catalytic enantioselective trifluoromethoxylation reaction has been reported until now. Here, we present an example of an asymmetric silver-catalysed intermolecular bromotrifluoromethoxylation of alkenes with trifluoromethyl arylsulfonate (TFMS) as a new trifluoromethoxylation reagent. Compared to other trifluoromethoxylation reagents, TFMS is easily prepared and thermally stable with good reactivity. In addition, this reaction is operationally simple, scalable and proceeds under mild reaction conditions. Furthermore, broad scope and good functional group compatibility has been demonstrated by application of the method to the bromotrifluoromethoxylation of double bonds in natural products and natural product derivatives.

Metal-sulfur type cell having improved positive electrode

DOEpatents

Dejonghe, Lutgard C.; Visco, Steven J.; Mailhe, Catherine C.; Armand, Michel B.

1989-01-01

An novel metal-sulfur type cell operable at a temperature of 200.degree. C. or less with an energy density of 150 Whrs/Kg or better is disclosed characterized by an organo-sulfur cathode formed from an organic-sulfur compound having the general formula, in its charged state, of (R(S).sub.y).sub.n wherein y=1 to 6; n=2 to 20; and R is one or more different aliphatic or aromatic organic moieties having 1 to 20 carbon atoms, which may include one or more oxygen, sulfur, or nitrogen heteroatoms when R comprisises one of more aromatic rings, or one or more oxygen, sulfur, nitrogen, or fluorine atoms associtated with the chain when R comprises an aliphatic chain, wherein the aliphatic group may be linear or branched, saturated or unsaturated, and wherein either the aliphatic chain or the aromatic ring may have substituted groups thereon.

Metal-sulfur type cell having improved positive electrode

DOEpatents

DeJonghe, L.C.; Visco, S.J.; Mailhe, C.C.; Armand, M.B.

1988-03-31

A novel metal-sulfur type cell operable at a temperature of 200/degree/C or less with an energy density of 150 Whrs/Kg or better is disclosed characterized by an organo-sulfur cathode formed from an organic-sulfur compound having the general formula, in its charged state, of (R(S)/sub y/)n wherein y = 1 to 6; n = 2 to 20; and R is one or more different aliphatic or aromatic organic moieties having 1 to 20 carbon atoms, which may include one or more oxygen, sulfur, or nitrogen heteroatoms when R comprises one or more aromatic rings, or one or more oxygen, sulfur, nitrogen, or fluorine atoms associated with the chain when R comprises an aliphatic chain, wherein the aliphatic group may be linear or branched, saturated or unsaturated, and wherein either the aliphatic chain or the aromatic ring may have substituted groups thereon. 4 figs.

Atmospheric Concentrations of Persistent Organic Pollutants in the Southern Ocean

NASA Astrophysics Data System (ADS)

Vlahos, P.; Edson, J.; Cifuentes, A.; McGillis, W. R.; Zappa, C.

2008-12-01

Long-range transport of persistent organic pollutant (POPs) is a global concern. Remote regions such as the Southern Ocean are greatly under-sampled though critical components in understanding POPs cycling. Over 20 high-volume air samples were collected in the Southern Ocean aboard the RV Brown during the GASEX III experiment between Mar 05 to April 9 2008. The relatively stationary platform (51S,38W) enabled the collection of a unique atmospheric time series at this open ocean station. Air sampling was also conducted across transects from Punto Arenas, Chile and to Montevideo, Uruguay. Samples were collected using glass sleeves packed with poly-urethane foam plugs and C-18 resin in order to collect target organic pollutants (per-fluorinated compounds, currently and historically used pesticides) in this under-sampled region. Here we present POPs concentrations and trends over the sampled period and compare variations with air parcel back trajectories to establish potential origins of their long-range transport.

Hydrolytically stable fluorinated metal-organic frameworks for energy-efficient dehydration

NASA Astrophysics Data System (ADS)

Cadiau, Amandine; Belmabkhout, Youssef; Adil, Karim; Bhatt, Prashant M.; Pillai, Renjith S.; Shkurenko, Aleksander; Martineau-Corcos, Charlotte; Maurin, Guillaume; Eddaoudi, Mohamed

2017-05-01

Natural gas must be dehydrated before it can be transported and used, but conventional drying agents such as activated alumina or inorganic molecular sieves require an energy-intensive desiccant-regeneration step. We report a hydrolytically stable fluorinated metal-organic framework, AlFFIVE-1-Ni (KAUST-8), with a periodic array of open metal coordination sites and fluorine moieties within the contracted square-shaped one-dimensional channel. This material selectively removed water vapor from gas streams containing CO2, N2, CH4, and higher hydrocarbons typical of natural gas, as well as selectively removed both H2O and CO2 in N2-containing streams. The complete desorption of the adsorbed water molecules contained by the AlFFIVE-1-Ni sorbent requires relatively moderate temperature (~105°C) and about half the energy input for commonly used desiccants.

Preparation of heterocyclic block copolymer from perfluoroalkylene oxide alpha, omega-diamidoximes

NASA Technical Reports Server (NTRS)

Ross, L. O.; Rosser, R. W.; Iannone, M. (Inventor)

1979-01-01

Diamidoxime monomers are intermolecularly and thermally condensed to form a heat and chemical resistant polymer containing 1,2,4-oxadiazole linkages with identical bivalent organic radicals or any combination of bivalent organic radicals selected from the group consisting of -(CX(sub 2))p-, wherein P ranges from 2 to 8 when X is fluorine and 2 to 18 when X is hydrogen, chlorine, nitro or aryl; arylene; and an oligometric or polymeric radical prepared by reacting a dicarboxylic acid halide with a fluorinated epoxide and having the formula: (CFY(OCF(sub 2)CFY)sub m)O(CX(sub 2))(sub p)O(CFYCF(sub 2)O)(sub n)CFY wherein Y is flourine or tryifluoromethyl, X is nitro, aryl, hydrogen, chlorine or fluorine, preferably the latter, p ranges from 1 to 18 and m+n ranges from 2 to 7.

Deuteration and fluorination of 1,3-bis(2-phenylethyl)pyrimidine-2,4,6(1H,3H,5H)-trione to improve its pharmacokinetic properties.

PubMed

Xia, Guoyao; Benmohamed, Radhia; Morimoto, Richard I; Kirsch, Donald R; Silverman, Richard B

2014-11-01

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the progressive loss of motor neurons, leading to muscle weakness, paralysis, and death, most often from respiratory failure. Over 200 pyrimidine-2,4,6-trione (PYT) small molecules, which prevent aggregation and reduce the associated toxicity of mutant superoxide dismutase 1 (SOD1) found in patients with familial ALS, have been synthesized and tested. One of the compounds (1,3-bis(2-phenylethyl)pyrimidine-2,4,6(1H,3H,5H)-trione, (1) was previously found to have an excellent combination of potency efficacy, and some desirable pharmacokinetic properties. To improve the solubility and metabolic stability properties of this compound, deuterium and fluorine were introduced into 1. New analogs with better solubility, plasma stability, and human microsome stability were identified. Copyright © 2014 Elsevier Ltd. All rights reserved.

Composite separators and redox flow batteries based on porous separators

DOEpatents

Li, Bin; Wei, Xiaoliang; Luo, Qingtao; Nie, Zimin; Wang, Wei; Sprenkle, Vincent L.

2016-01-12

Composite separators having a porous structure and including acid-stable, hydrophilic, inorganic particles enmeshed in a substantially fully fluorinated polyolefin matrix can be utilized in a number of applications. The inorganic particles can provide hydrophilic characteristics. The pores of the separator result in good selectivity and electrical conductivity. The fluorinated polymeric backbone can result in high chemical stability. Accordingly, one application of the composite separators is in redox flow batteries as low cost membranes. In such applications, the composite separator can also enable additional property-enhancing features compared to ion-exchange membranes. For example, simple capacity control can be achieved through hydraulic pressure by balancing the volumes of electrolyte on each side of the separator. While a porous separator can also allow for volume and pressure regulation, in RFBs that utilize corrosive and/or oxidizing compounds, the composite separators described herein are preferable for their robustness in the presence of such compounds.

Cytotoxicity and utility of 1-indanone in the synthesis of some new heterocycles.

PubMed

Hegazi, Bahira; Mohamed, Hanan Ahmed; Dawood, Kamal Mohamed; Badria, Farid Abdel-Rahem

2010-04-01

Benzo[d]imidazole 3 and 1,2,4-triazin-5(2H)-one 6 were prepared by the reaction of starting ethyl (3-hydroxy-1H-inden-2-yl)(oxo)-acetate 2 with o-phenylenediamine and thiosemicarbazide respectively. Reaction of 1,4-dihydro-1-phenylindeno[1,2-c]pyrazole-3-carbohydrazide 8 with phenylisothiocyanate gave thiosemicarbazide 9, and its reaction with chloroacetic acid or phenacylbromides led to the formation of thiazolidinone-4-one 10 or 1,3-thiazoles 12a, b. The reactivity of hydrazide 8 towards fluorinated aldehyde, phthalic anhydride, and hydrazonoyl chlorides 15a, b was studied to give fluorinated hydrazones, imide bis-hydrazones 13-16. The newly synthesized compounds were screened for their cytotoxic activities and compounds 6, 8, 9 and 10 were found the most potentially cytotoxic. The detailed synthesis, spectroscopic and biological data are reported.

Zinc oxyfluoride transparent conductor

DOEpatents

Gordon, Roy G.

1991-02-05

Transparent, electrically conductive and infrared-reflective films of zinc oxyfluoride are produced by chemical vapor deposition from vapor mixtures of zinc, oxygen and fluorine-containing compounds. The substitution of fluorine for some of the oxygen in zinc oxide results in dramatic increases in the electrical conductivity. For example, diethyl zinc, ethyl alcohol and hexafluoropropene vapors are reacted over a glass surface at 400.degree. C. to form a visibly transparent, electrically conductive, infrared reflective and ultraviolet absorptive film of zinc oxyfluoride. Such films are useful in liquid crystal display devices, solar cells, electrochromic absorbers and reflectors, energy-conserving heat mirrors, and antistatic coatings.

Fluoroalkenylphosphonates

NASA Astrophysics Data System (ADS)

Kadyrov, A. A.; Rokhlin, E. M.

1988-09-01

In this review we survey the methods for the preparation of derivatives of fluoroalkenylphosphonic acid and their reactions. The main methods for obtaining these compounds are based on the reactions of fluoroolefins with phosphites and also on the elimination of halogens, hydrogen halides and alkyl halides from fluoroalkylphosphonates or fluorine-containing phosphorus ylides. The chemical properties of fluoroalkenylphosphonates are due to the combined effect of the fluorine atoms and the phosphonate group. Their reactions with different reagents leads to modifications of the phosphonate group, addition to the C=C bond, replacement of the vinyl halogen atom, and cleavage of the C-P bond. The bibliography includes 96 references.

Synthesis, molecular structure and spectroscopic investigations of novel fluorinated spiro heterocycles.

PubMed

Islam, Mohammad Shahidul; Al-Majid, Abdullah Mohammed; Barakat, Assem; Soliman, Saied M; Ghabbour, Hazem A; Quah, Ching Kheng; Fun, Hoong-Kun

2015-05-07

This paper describes an efficient and regioselective method for the synthesis of novel fluorinated spiro-heterocycles in excellent yield by cascade [5+1] double Michael addition reactions. The compounds 7,11-bis(4-fluorophenyl)-2,4-dimethyl- 2,4-diazaspiro[5.5] undecane-1,3,5,9-tetraone (3a) and 2,4-dimethyl-7,11-bis (4-(trifluoromethyl)phenyl)-2,4-diazaspiro[5.5]undecane-1,3,5,9-tetraone (3b) were characterized by single-crystal X-ray diffraction, FT-IR and NMR techniques. The optimized geometrical parameters, infrared vibrational frequencies and NMR chemical shifts of the studied compounds have also been calculated using the density functional theory (DFT) method, using Becke-3-Lee-Yang-Parr functional and the 6-311G(d,p) basis set. There is good agreement between the experimentally determined structural parameters, vibrational frequencies and NMR chemical shifts of the studied compounds and those predicted theoretically. The calculated natural atomic charges using NBO method showed higher polarity of 3a compared to 3b.The calculated electronic spectra are also discussed based on the TD-DFT calculations.

Development of Candidates for Positron Emission Tomography (PET) Imaging of Ghrelin Receptor in Disease: Design, Synthesis, and Evaluation of Fluorine-Bearing Quinazolinone Derivatives.

PubMed

Hou, Jinqiang; Kovacs, Michael S; Dhanvantari, Savita; Luyt, Leonard G

2018-02-08

Molecular imaging with positron emission tomography (PET) is an attractive platform for noninvasive detection and assessment of disease. The development of a PET imaging agent targeting the ghrelin receptor (growth hormone secretagogue receptor type 1a or GHS-R1a) has the potential to lead to the detection and assessment of the higher than normal expression of GHS-R1a in diseases such as prostate, breast, and ovarian cancer. To enable the development of 18 F radiopharmaceuticals, we have designed and synthesized three series of quinazolinone derivatives, resulting in the identification of two compound (5i, 17) with subnanomolar binding affinity and one fluorine-bearing compound (10b) with picomolar binding affinity (20 pM), representing the highest binding affinity for GHS-R1a reported to date. Two lead compounds (5b, IC 50 = 20.6 nM; 5e, IC 50 = 9.3 nM) were successfully 18 F-radiolabeled with radiochemical purity of greater than 99%. Molecular modeling studies were performed to shed light on ligand-receptor interactions.

USSR Report, Science and Technology Policy.

DTIC Science & Technology

1987-03-12

producing hydrogen peroxide and monocarboxylic acids for the oil-free production of varnishes and paints. The entire world is using this resource...widely used in the paint, varnish , and food industry, medicine, and other sectors. The All-Union Scientific Seminar that opened on 17 September in...the form of a compound containing fluorine ; compounds of tetravalent nickel were synthesized; lanthanide and transuranic elements have been produced

Elastomeric fluorinated polyurethane coatings for nontoxic fouling control.

PubMed

Brady, Robert F; Aronson, Carl L

2003-04-01

Nontoxic antifouling coatings have been investigated for many years as possible successors to toxic antifouling paints. Polymers containing fluorine or silicone have been tested and each has been shown to be partially effective for different reasons. This paper describes a new coating which combines the best features of fluorinated and silicone coatings and is non-toxic. Four fluorinated elastomers were prepared and tested for fouling resistance during a full fouling season. The surface energy and mechanical properties of each polymer were measured and correlated to fouling performance. One of the elastomers was shown to foul slowly, clean easily, be durable in the marine environment and organisms bonded to it only weakly. The surface energy, elastic modulus, and thickness of the elastomer may be varied as desired over wide ranges to meet differing performance requirements.

A practical and catalyst-free trifluoroethylation reaction of amines using trifluoroacetic acid

NASA Astrophysics Data System (ADS)

Andrews, Keith G.; Faizova, Radmila; Denton, Ross M.

2017-06-01

Amines are a fundamentally important class of biologically active compounds and the ability to manipulate their physicochemical properties through the introduction of fluorine is of paramount importance in medicinal chemistry. Current synthesis methods for the construction of fluorinated amines rely on air and moisture sensitive reagents that require special handling or harsh reductants that limit functionality. Here we report practical, catalyst-free, reductive trifluoroethylation reactions of free amines exhibiting remarkable functional group tolerance. The reactions proceed in conventional glassware without rigorous exclusion of either moisture or oxygen, and use trifluoroacetic acid as a stable and inexpensive fluorine source. The new methods provide access to a wide range of medicinally relevant functionalized tertiary β-fluoroalkylamine cores, either through direct trifluoroethylation of secondary amines or via a three-component coupling of primary amines, aldehydes and trifluoroacetic acid. A reduction of in situ-generated silyl ester species is proposed to account for the reductive selectivity observed.

Register of specialized sources for information on selected fuels and oxidizers. [rocket propellants, bibliographies

NASA Technical Reports Server (NTRS)

Ludtke, P. R.

1975-01-01

Thirty-eight (38) organizations are listed and described that catalog and file information in their data systems on fuel and oxidizers. The fuels include hydrogen, methane and hydrazine-type fuels; the oxidizers include oxygen, fluorine, flox, nitrogen tetroxide and ozone. The type of available information covers thermophysical properties, propellant systems, propellant fires-control-extinguishment, propellant explosions, propellant combustion, propellant safety, and fluorine chemistry. These organizations have assembled and collated their information so that it will be useful in the solution of engineering problems.

Enhanced diode characteristics of organic solar cell with silanized fluorine doped tin oxide electrode

NASA Astrophysics Data System (ADS)

Sachdeva, Sheenam; Sharma, Sameeksha; Singh, Devinder; Tripathi, S. K.

2018-05-01

To investigate the diode characteristics of organic solar cell based on the planar heterojunction of 4,4'- cyclohexylidenebis[N,N-bis(4-methylphenyl)benzenamine] (TAPC) and fullerene (C70), we report the use of silanized fluorine-doped tin oxide (FTO) anode with N1-(3-trimethoxysilylpropyl)diethyltriamine (DETA) forming monolayer. The use of silanized FTO results in the decrease of saturation current density and diode ideality factor of the device. Such silanized FTO anode is found to enhance the material quality and improve the device properties.

Dielectric Constant and Loss Data. Part 4

DTIC Science & Technology

1980-12-01

Fluorinated ethers, Organic Chemicals Dept., P.R.-194Dow Chemical "Dowtherm" A, P.R.-194 T ORg C a p - Dew Corning Corp., IV-26, 27, 41, 42, "HVITON...Esso "Teresso" oil, V-78; P.R.-195 and MFl16, V-15 "Estawax", IV-57 "Eccosorb" MFll7, V-15, 242 Ethers, fluorinated , P.R.-194 Eggwhite. P.R.-202 "Ethocel...PPG, 8-20 Flourglas laminate, 9-33 "Gafite" cast polymer, IV-34 Fluorinated ethers, P.R.-194 Gasoline, aviation, 100 and 91 octane, Fluorcarbon

Controlling molecular transport in minimal emulsions

NASA Astrophysics Data System (ADS)

Gruner, Philipp; Riechers, Birte; Semin, Benoît; Lim, Jiseok; Johnston, Abigail; Short, Kathleen; Baret, Jean-Christophe

2016-01-01

Emulsions are metastable dispersions in which molecular transport is a major mechanism driving the system towards its state of minimal energy. Determining the underlying mechanisms of molecular transport between droplets is challenging due to the complexity of a typical emulsion system. Here we introduce the concept of `minimal emulsions', which are controlled emulsions produced using microfluidic tools, simplifying an emulsion down to its minimal set of relevant parameters. We use these minimal emulsions to unravel the fundamentals of transport of small organic molecules in water-in-fluorinated-oil emulsions, a system of great interest for biotechnological applications. Our results are of practical relevance to guarantee a sustainable compartmentalization of compounds in droplet microreactors and to design new strategies for the dynamic control of droplet compositions.

Fluorinated Compounds in U.S. Fast Food Packaging

EPA Science Inventory

Per- and polyfluoroalkyl substances (PFASs) are highly persistent synthetic chemicals, some of which have been associated with cancer, developmental toxicity, immunotoxicity, and other health effects. PFASs in grease-resistant food packaging can leach into food and increase dieta...

Process for the production of 5'-deoxy-5-(/sup 18/F)fluorouridine

DOEpatents

Shiue, C.Y.; Wolf, A.P.; Friedkin, M.

1983-08-10

Process for the production of 5'-deoxy-5-fluorouridine and the corresponding /sup 18/F compound by the reaction of fluorine or acetyl hypofluorite with 2', 3'-di-O-acetyl-5'-deoxyuridine followed by hydrolysis.

Solvent Extraction of Sodium Hydroxide Using Alkylphenols and Fluorinated Alcohols: Understanding the Extraction Mechanism by Equilibrium Modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, Hyun-Ah; Engle, Nancy L.; Bonnesen Peter V.

2004-03-29

In the present work, it has been the aim to examine extraction efficiencies of nine proton-ionizable alcohols (HAs) in 1-octanol and to identify both the controlling equilibria and predominant species involved in the extraction process within a thermochemical model. Distribution ratios for sodium (DNa) extraction were measured as a function of organic-phase HA and aqueous-phase NaOH molarity at 25 °C. Extraction efficiency follows the expected order of acidity of the HAs, 4-(tert-octyl) phenol (HA 1a) and 4-noctyl- a,a-bis-(trifluoromethyl)benzyl alcohol (HA 2a) being the most efficient extractants among the compounds tested. By use of the equilibrium-modeling program SXLSQI, a model formore » the extraction of NaOH has been advanced based on an ion-pair extraction by the diluent to give organic-phase Na+OH- and corresponding free ions and cation exchange by the weak acids to form monomeric organic-phase Na+A- and corresponding free organic-phase ions.« less

Development of a nucleotide sugar purification method using a mixed mode column & mass spectrometry detection.

PubMed

Eastwood, Heather; Xia, Fang; Lo, Mei-Chu; Zhou, Jing; Jordan, John B; McCarter, John; Barnhart, Wesley W; Gahm, Kyung-Hyun

2015-11-10

Analysis of nucleotide sugars, nucleoside di- and triphosphates and sugar-phosphates is an essential step in the process of understanding enzymatic pathways. A facile and rapid separation method was developed to analyze these compounds present in an enzymatic reaction mixture utilized to produce nucleotide sugars. The Primesep SB column explored in this study utilizes hydrophobic interactions as well as electrostatic interactions with the phosphoric portion of the nucleotide sugars. Ammonium formate buffer was selected due to its compatibility with mass spectrometry. Negative ion mode mass spectrometry was adopted for detection of the sugar phosphate (fucose-1-phophate), as the compound is not amenable to UV detection. Various mobile phase conditions such as pH, buffer concentration and organic modifier were explored. The semi-preparative separation method was developed to prepare 30mg of the nucleotide sugar. (19)F NMR was utilized to determine purity of the purified fluorinated nucleotide sugar. The collected nucleotide sugar was found to be 99% pure. Published by Elsevier B.V.

The Curious Case of Fluorination of Conjugated Polymers for Solar Cells.

PubMed

Zhang, Qianqian; Kelly, Mary Allison; Bauer, Nicole; You, Wei

2017-09-19

Organic solar cells (OSCs) have been a rising star in the field of renewable energy since the introduction of the bulk heterojunction (BHJ) in 1992. Recent advances have pushed the efficiencies of OSCs to over 13%, an impressive accomplishment via collaborative efforts in rational materials design and synthesis, careful device engineering, and fundamental understanding of device physics. Throughout these endeavors, several design principles for the conjugated donor polymers used in such solar cells have emerged, including optimizing the conjugated backbone with judicious selection of building blocks, side-chain engineering, and substituents. Among all of the substituents, fluorine is probably the most popular one; improved device characteristics with fluorination have frequently been reported for a wide range of conjugated polymers, in particular, donor-acceptor (D-A)-type polymers. Herein we examine the effect of fluorination on the device performance of solar cells as a function of the position of fluorination (on the acceptor unit or on the donor unit), aiming to outline a clear understanding of the benefits of this curious substituent. As fluorination of the acceptor unit is the most adopted strategy for D-A polymers, we first discuss the effect of fluorination of the acceptor units, highlighting the five most widely utilized acceptor units. While improved device efficiency has been widely observed with fluorinated acceptor units, the underlying reasons vary from case to case and highly depend on the chemical structure of the polymer. Second, the effect of fluorination of the donor unit is addressed. Here we focus on four donor units that have been most studied with fluorination. While device-performance-enhancing effects by fluorination of the donor units have also been observed, it is less clear that fluorine will always benefit the efficiency of the OSC, as there are several cases where the efficiency drops, in particular with "over-fluorination", i.e., when too many fluorine substituents are incorporated. Finally, while this Account focuses on studies in which the polymer is paired with fullerene derivatives as the electron accepting materials, non-fullerene acceptors (NFAs) are quickly becoming key players in the field of OSCs. The effect of fluorination of the polymers on the device performance may be different when NFAs are used as the electron-accepting materials, which remains to be investigated. However, the design of fluorinated polymers may provide guidelines for the design of more efficient NFAs. Indeed, the current highest-performing OSC (∼13%) features fluorination on both the donor polymer and the non-fullerene acceptor.

Weak interactions involving organic fluorine: analysis of structural motifs in Flunazirine and Haloperidol

NASA Astrophysics Data System (ADS)

Prasanna, M. D.; Row, T. N. Guru

2001-05-01

The crystal structure of Flunazirine, an anticonvulsant drug, is analyzed in terms of intermolecular interactions involving fluorine. The structure displays motifs formed by only weak interactions C-H⋯F and C-H⋯π. The motifs thus generated show cavities, which could serve as hosts for complexation. The structure of Flunazirine displays cavities formed by C-H⋯F and C-H⋯π interactions. Haloperidol, an antipsychotic drug, shows F⋯F interactions in the crystalline lattice in lieu of Cl⋯Cl interactions. However, strong O-H⋯N interactions dominate packing. The salient features of the two structures in terms of intermolecular interactions reveal, even though organic fluorine has lower tendency to engage in hydrogen bonding and F⋯F interactions, these interactions could play a significant role in the design of molecular assemblies via crystal engineering.

A novel UV-photolysis approach with acetone and isopropyl alcohol for the rapid determination of fluoride in organofluorine-containing drugs by spectrophotometry.

PubMed

Mullapudi, Venkata Balarama Krishna; Dheram, Karunasagar

2018-01-01

A UV photolysis decomposition (UVPD) method for the determination of fluoride in fluorine containing pharmaceuticals by spectrophotometry is reported. It is based on the use of high intensity UV-irradiation in the presence of a digesting solution comprising a mixture of acetone and isopropanol. For the optimization of the UVPD procedure, three bulk drugs (levofloxacin, nebivolol and efavirenz) were chosen as representatives of three diverse compounds containing a single fluorine atom, two fluorine atoms, and trifluoromethyl groups respectively. Operational conditions of the UVPD method, such as concentration and volume of reagents (acetone and isopropyl alcohol), and UV irradiation time (1-6 minutes) were optimized. The efficiency of digestion was evaluated by the determination of fluoride in sample digests. Using the developed method, it was possible for complete conversion of the organofluoride to free fluoride ion for its subsequent determination by spectrophotometry based on bleaching of Zr-xylenol orange-color complex. Quantitative recovery (>98%) of the fluorine in the drug samples could be achieved using a mixture of 2% acetone + 2% isopropyl alcohol + 0.003% Na 2 CO 3 in just 5 minutes of UV irradiation, which can be considered an important aspect considering the difficulties involved in the cleavage of the CF bond. Accuracy was evaluated by comparison of results obtained by the UVPD method with the values estimated using formula weight of the compound and no statistical difference was observed between the results. Therefore, the proposed method is suitable for application in routine analysis of fluoride in organofluorine-containing drugs. Copyright © 2016. Published by Elsevier B.V.

Transition-metal-free visible-light photoredox catalysis at room-temperature for decarboxylative fluorination of aliphatic carboxylic acids by organic dyes.

PubMed

Wu, Xinxin; Meng, Chunna; Yuan, Xiaoqian; Jia, Xiaotong; Qian, Xuhong; Ye, Jinxing

2015-07-28

We report herein an efficient, general and green method for decarboxylative fluorination of aliphatic carboxylic acids. By using a transition-metal-free, organocatalytic photoredox system, the reaction of various aliphatic carboxylic acids with the Selectfluor reagent afforded the corresponding alkyl fluorides in satisfactory yields under visible light irradiation at room temperature.

FLUORINATED SURFACTANTS IN THE GREAT LAKES - YESTERDAY, TODAY, AND TOMORROW

EPA Science Inventory

Perfluorooctane surfactants have been reported in biota, water, and air samples worldwide. Despite these reports, the main environmental sources of these compounds remain undefined. As a presentation to the emerging chemicals workshop of the International Joint Commission on Grea...

NRL Review, 1994. (Naval Research Lab)

DTIC Science & Technology

1994-03-01

analysis of Brockway (left) at the University of Michigan in gaseous state fluorine and hydrocarbon 1945 compounds . Both she and her husband 10 would later... sorption , desorption, and abstraction processes general, and CVD growth in particular, can create a dynamic balance that leaves some open occur principally...4]. Natural compounds of the inner diameter of the cylinder and the extracted from a number of marine animals and polymeric carrier that may be

Development of acetophenone ligands as potential neuroimaging agents for cholinesterases.

PubMed

Jollymore-Hughes, Courtney T; Pottie, Ian R; Martin, Earl; Rosenberry, Terrone L; Darvesh, Sultan

2016-11-01

Association of cholinesterase with β-amyloid plaques and tau neurofibrillary tangles in Alzheimer's disease offers an opportunity to detect disease pathology during life. Achieving this requires development of radiolabelled cholinesterase ligands with high enzyme affinity. Various fluorinated acetophenone derivatives bind to acetylcholinesterase with high affinity, including 2,2,2-trifluoro-1-(3-dimethylaminophenyl)ethanone (1) and 1-(3-tert-butylphenyl)-2,2,2-trifluoroethanone (2). Such compounds also offer potential for incorporation of radioactive fluorine ( 18 F) for Positron Emission Tomography (PET) imaging of cholinesterases in association with Alzheimer's disease pathology in the living brain. Here we describe the synthesis of two meta-substituted chlorodifluoroacetophenones using a Weinreb amide strategy and their rapid conversion to the corresponding trifluoro derivatives through nucleophilic substitution by fluoride ion, in a reaction amenable to incorporating 18 F for PET imaging. In vitro kinetic analysis indicates tight binding of the trifluoro derivatives to cholinesterases. Compound 1 has a K i value of 7nM for acetylcholinesterase and 1300nM for butyrylcholinesterase while for compound 2 these values are 0.4nM and 26nM, respectively. Tight binding of these compounds to cholinesterase encourages their development for PET imaging detection of cholinesterase associated with Alzheimer's disease pathology. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Fluorine speciation and its distribution characteristics in selected agricultural soils of North China Plain].

PubMed

Yi, Chun-Yao; Wang, Bing-Guo; Jin, Meng-Gui

2013-08-01

The objectives of this study were to study fluorine speciation and its distribution characteristics in the cultivated soils of wheat-corn fields at the typical areas, the North China Plain. The fluorine contents in cultivated soils and profile soils were measured by consecutive extraction. The results showed that the soil total fluorine (T-F) content at typical areas in the North China Plain ranged from 338.31 mg x kg(-1) to 781.67 mg x kg(-1), with a mean of 430.46 mg x kg(-1). The soil fluorine speciation with the highest content was Residual-Fluorine (Res-F), with a mean of 402.73 mg x kg(-1). The average content of Water soluble Fluorine (Ws-F) was 14.39 mg x kg(-1). The result indicated that the cultivated soil in the study area was at a relatively high fluoride pollution level, which may be harmful to human health and the ecological environment. The contents of Organic Fluorine (Or-F) and Fe/Mn Oxide-Fluorine (Fe/ Mn-F) were also quite high, with a mean of 8.90 mg x kg(-1) and 4.10 mg x kg(-1), respectively. The exchangeable fluorine (Ex-F) only had a very small amount of 0.33 mg x kg(-1). Soil Ws-F was positively correlated with soil pH and CEC, while it was negatively correlated with the percentage of soil clay. The content of soil Fe/Mn-F was positively correlated with soil pH, CEC and the sand grain content percentage, while it was negatively correlated with the clay grain content percentage. The soil pH value had the most significant influence on the water soluble fluorine (Ws-F) and Fe/Mn Oxide-Fluorine (Fe/Mn-F), and the soil CEC had the most significant influence on the soil total fluorine (T-F) and residual-Fluorine (Res-F) by stepwise regression analysis. In the soil profiles, the T-F content appeared as peaks and valleys representing the change of the soil lithology in the vadose zone. The Ws-F in the soil profiles mainly changed in the depth of 0-100 cm near the surface soil and was little influenced by the soil lithology. But it was strongly influenced by the soil pH, and was positively correlated with the soil pH. This study can provide a scientific evidence for soil fluorine pollution, prevention and a theoretical basis for soil fluorine mobility and its influence on ecology and environment.

Two generators to produce SI-traceable reference gas mixtures for reactive compounds at atmospheric levels

NASA Astrophysics Data System (ADS)

Pascale, C.; Guillevic, M.; Ackermann, A.; Leuenberger, D.; Niederhauser, B.

2017-12-01

To answer the needs of air quality and climate monitoring networks, two new gas generators were developed and manufactured at METAS in order to dynamically generate SI-traceable reference gas mixtures for reactive compounds at atmospheric concentrations. The technical features of the transportable generators allow for the realization of such gas standards for reactive compounds (e.g. NO2, volatile organic compounds) in the nmol · mol-1 range (ReGaS2), and fluorinated gases in the pmol ṡ mol-1 range (ReGaS3). The generation method is based on permeation and dynamic dilution. The transportable generators have multiple individual permeation chambers allowing for the generation of mixtures containing up to five different compounds. This mixture is then diluted using mass flow controllers, thus making the production process adaptable to generate the required amount of substance fraction. All parts of ReGaS2 in contact with the gas mixture are coated to reduce adsorption/desorption processes. Each input parameter required to calculate the generated amount of substance fraction is calibrated with SI-primary standards. The stability and reproducibility of the generated amount of substance fractions were tested with NO2 for ReGaS2 and HFC-125 for ReGaS3. They demonstrate stability over 1-4 d better than 0.4% and 0.8%, respectively, and reproducibility better than 0.7% and 1%, respectively. Finally, the relative expanded uncertainty of the generated amount of substance fraction is smaller than 3% with the major contributions coming from the uncertainty of the permeation rate and/or of the purity of the matrix gas. These relative expanded uncertainties meet then the needs of the data quality objectives fixed by the World Meteorological Organization.

Nerve agent analogues that produce authentic soman, sarin, tabun, and cyclohexyl methylphosphonate-modified human butyrylcholinesterase.

PubMed

Gilley, Cynthia; MacDonald, Mary; Nachon, Florian; Schopfer, Lawrence M; Zhang, Jun; Cashman, John R; Lockridge, Oksana

2009-10-01

The goal was to test 14 nerve agent model compounds of soman, sarin, tabun, and cyclohexyl methylphosphonofluoridate (GF) for their suitability as substitutes for true nerve agents. We wanted to know whether the model compounds would form the identical covalent adduct with human butyrylcholinesterase that is produced by reaction with true nerve agents. Nerve agent model compounds containing thiocholine or thiomethyl in place of fluorine or cyanide were synthesized as Sp and Rp stereoisomers. Purified human butyrylcholinesterase was treated with a 45-fold molar excess of nerve agent analogue at pH 7.4 for 17 h at 21 degrees C. The protein was denatured by boiling and was digested with trypsin. Aged and nonaged active site peptide adducts were quantified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry of the tryptic digest mixture. The active site peptides were isolated by HPLC and analyzed by MALDI-TOF-TOF mass spectrometry. Serine 198 of butyrylcholinesterase was covalently modified by all 14 compounds. Thiocholine was the leaving group in all compounds that had thiocholine in place of fluorine or cyanide. Thiomethyl was the leaving group in the GF thiomethyl compounds. However, sarin thiomethyl compounds released either thiomethyl or isopropyl, while soman thiomethyl compounds released either thiomethyl or pinacolyl. Thiocholine compounds reacted more rapidly with butyrylcholinesterase than thiomethyl compounds. Labeling with the model compounds resulted in aged adducts that had lost the O-alkyl group (O-ethyl for tabun, O-cyclohexyl for GF, isopropyl for sarin, and pinacolyl for soman) in addition to the thiocholine or thiomethyl group. The nerve agent model compounds containing thiocholine and the GF thiomethyl analogue were found to be suitable substitutes for true soman, sarin, tabun, and GF in terms of the adduct that they produced with human butyrylcholinesterase. However, the soman and sarin thiomethyl compounds yielded two types of adducts, one of which was thiomethyl phosphonate, a modification not found after treatment with authentic soman and sarin.

Liquid-phase and vapor-phase dehydration of organic/water solutions

DOEpatents

Huang, Yu [Palo Alto, CA; Ly, Jennifer [San Jose, CA; Aldajani, Tiem [San Jose, CA; Baker, Richard W [Palo Alto, CA

2011-08-23

Processes for dehydrating an organic/water solution by pervaporation or vapor separation using fluorinated membranes. The processes are particularly useful for treating mixtures containing light organic components, such as ethanol, isopropanol or acetic acid.

Are Developmentally-Exposed C57BL/6 Mice Insensitive to Suppression of TDAR by PFOA?

EPA Science Inventory

Perfluorooctanoic acid (PFOA) is an environmentally persistent fluorinated compound that is present in biological samples worldwide and associated with multisystem toxicity in laboratory animal models. Several studies have reported suppression of T-cell-dependent antibody respons...

Fluorine

USGS Publications Warehouse

Hayes, Timothy S.; Miller, M. Michael; Orris, Greta J.; Piatak, Nadine M.; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

2017-12-19

Fluorine compounds are essential in numerous chemical and manufacturing processes. Fluorspar is the commercial name for fluorite (isometric CaF2), which is the only fluorine mineral that is mined on a large scale. Fluorspar is used directly as a fluxing material and as an additive in different manufacturing processes. It is the source of fluorine in the production of hydrogen fluoride or hydrofluoric acid, which is used as the feedstock for numerous organic and inorganic chemical compounds.The United States was the world’s leading producer of fluorspar until the mid-1950s. In the mid-1970s, the U.S. fluorspar mining industry began to decline because of foreign competition. By 1982, there was essentially only a single U.S. producer left, and that company ceased mining in 1996. Consumption of fluorspar in the United States peaked in the early 1970s, which was also the peak period of U.S. steel production. Since then, U.S. fluorspar consumption has decreased substantially; the United States has nonetheless increased its imports of downstream fluorine compounds, such as, in order of tonnage imported, hydrofluoric acid, aluminum fluoride, and cryolite. This combination of no U.S. production (until recently) and high levels of consumption has made the United States the world’s leading fluorspar-importing country, in all its various forms.The number of fluorspar-exporting countries has decreased substantially in recent decades, and, as a result, the United States has become dependent on just a few countries to supply its needs. In 2013, the United States imported the majority of its fluorspar from three countries, which were, in descending order of the amount imported, Mexico, China, and South Africa.Geologically, in igneous systems, fluorine is one of a number of elements that are “incompatible.” These incompatible elements become concentrated in the residual magma while the common silicates crystallize upon magma ascent and cooling, leading to relatively high fluorine concentrations in the more evolved or differentiated igneous rocks and in hydrothermal deposits associated with those evolved igneous rocks. In sedimentary rocks, fluorine’s highest concentrations are found in phosphorites because fluorine substitutes for hydroxyl ions in apatite, which leads to fluorine concentrations of, typically, from 2 to 4 weight percent in phosphorites. Because of the presence of fluorine, phosphate fertilizer manufacturers can produce a fluorosilicic acid byproduct. Most deposits mined for fluorine are hydrothermal, however, and consist of fluorine minerals that precipitated from hot water. Magmatic brines and brines from deep within sedimentary basins that have high concentrations of dissolved fluoride are the mineralizing fluids for various types of hydrothermal fluorspar deposits. Relatively dilute hydrothermal fluids that formed in some volcanic rocks can also transport sufficient fluoride to form a high-grade fluorspar deposit. Fluorite has low solubility in a common range of hydrothermal temperatures, particularly from about 160 degrees Celsius (°C) down to 60 °C. The increasing fluorite solubility below 60 °C partly explains why some water with exceptionally high levels of dissolved fluorine are found even at ambient temperatures in evaporitic lake basins in some East African Rift valleys in Kenya and Tanzania. The geologic conditions that led to the high concentrations there are known to exist in a number of other places in the world as well, including, perhaps, places in the Basin and Range province of the United States.Eight minerals or mineral groups have sufficient fluorine in their structures to be considered as possible ores of the element; they are bastnaesite (also spelled bastnäsite; and other fluorocarbonates), cryolite, sellaite, villiaumite, fluorite, fluorapatite (in phosphorites), various phyllosilicates, and topaz. Fluorite is currently the only mineral that is mined for fluorine, and nomineral except fluorite is likely to become a source of commercially produced fluorine as a primary product as long as supplies from relatively thick and high-grade fluorite deposits continue to be available.At least seven classes (which include one subclass) of hydrothermal fluorite deposits are recognized; they are classified according to their tectonic and (or) magmatic settings, as follows: (1) carbonatite-related fluorspar deposits; (2) alkaline-intrusion-related fluorspar deposits; (3) alkaline-volcanic-related epithermal fluorspar deposits; (4) Mississippi Valley-type fluorspar deposits (and a subclass of salt-related carbonate-hosted fluorspar deposits); (5) fluorspar deposits related to strongly differentiated granites; (6) subalkaline-volcanic-related epithermal fluospar deposits; and (7) fluorspar deposits that appear to be conformable within tuffaceous limy lacustrine sediments. An eighth class (not hydrothermal) is that of fluorspar deposits concentrated in soils and weathered zones; that is, residual fluorspar deposits. Generally, fluorspar deposits related to strongly differentiated granites have larger tonnages and lower grades than carbonatite-related fluorspar deposits, which, in turn, have larger tonnages and lower grades than fluorspar vein deposits from various other classes.The United States has a few identified resources of fluorspar, most notably the Klondike II property in the Illinois- Kentucky fluorspar district located about 8 kilometers southwest of Salem, Kentucky, which has a large vein that contains at least 1.6 million metric tons at a grade of 60 percent CaF2 (Feytis, 2009). Additional fluorspar resources of lower grade but larger tonnage have been identified at Hicks Dome in the Illinois-Kentucky fluorspar district and at Lost River near the western tip of the Seward Peninsula in Alaska, along with a couple of dozen smaller, higher grade resources.Internationally, new mines that either opened before the beginning of 2013 or were scheduled to open soon after that time include the Nui Phao tungsten-fluorspar-bismuth-copper-gold deposit in northern Vietnam; the St. Lawrence project in Newfoundland, Canada, which is located in a well-known fluorspar district; the Bamianshan deposit, which is related to a strongly differentiated granite in northwestern Zhejiang Province, China, near some of that Province’s large, subalkaline-volcanic-related epithermal veins; and the Nokeng project in South Africa, which is also related to a strongly differentiated granite. Other deposits in northwestern Australia, Nevada (United States), Norway, South Africa, and Sweden have been identified and could be put into production within just a few years.Among undiscovered resources, an interesting possibility might be to produce a fluorine product from evaporitic, high-fluorine, high-pH sodium-carbonate brines like Lake Magadi (Kenya) and Lake Natron (Tanzania) in Africa’s Eastern Rift Valley. In addition, apparently conformable fluorspar deposits in tuffaceous limy lacustrine sediments, such as those in Italy, are likely to occur in similar young alkalic volcanic settings elsewhere in the world.Modern geophysical and geochemical exploration techniques have typically not been brought to bear in exploration for new fluorspar deposits, although such techniques are likely to be used in future exploration. The tendency for fluorine to dissolve in significant concentrations in water at low temperature allows both surface water and groundwater to be used as sampling media in geochemical exploration. Evolved granite-related fluorspar deposits may be particularly susceptible to geophysical exploration methods because crystalline rocks that form a basement to sedimentary sections can be approximately defined with gravity and magnetic methods, and magnetite-bearing skarns can be directly detected with magnetic surveys.Environmental considerations of fluorine mining focus especially on drinking water, where high fluorine concentrations can lead to tooth decay; dental and skeletal fluorosis; and bone and cartilage conditions, including genu valgum, which is the crippling bone deformity more commonly known as knock knee. Trace amounts of other elements in fluorspar ores are a concern at some deposits; for example, high beryllium concentrations in alkaline-volcanic-related epithermal deposits or high cadmium concentrations associated with Mississippi Valley-type and salt-related carbonate-hosted fluorspar deposits.Future research might include testing whether fluorine can be extracted economically from high-pH, sodium-carbonate brines and exploring for new occurrences of apparently conformable fluorspar deposits in tuffaceous limy lacustrine sediments outside of the Latium Region of Italy. Other promising new areas of research could be studies of fluorspar deposit fluid inclusion compositions by quadrupole mass spectrometry, by noble gas mass spectrometry on irradiated fluid inclusions, or by chlorine isotopes, while also measuring the chemistry of the same fluid inclusions either by bulk crush-and-leach methods or by laser ablation-inductively coupled plasma mass spectrometry. Advanced studies of fluid inclusion chemistry could be applied beneficially to some of the enigmatic large epithermal fluorspar veins at various places in the world, where they might determine those deposits’ possible relationships to igneous intrusions, or to dissolved salt, or to heated meteoric water in volcanic sections, or perhaps to all three. This knowledge could help focus new exploration.

Perfluoroalkyl and polyfluoroalkyl substances in the environment: terminology, classification, and origins.

PubMed

Buck, Robert C; Franklin, James; Berger, Urs; Conder, Jason M; Cousins, Ian T; de Voogt, Pim; Jensen, Allan Astrup; Kannan, Kurunthachalam; Mabury, Scott A; van Leeuwen, Stefan P J

2011-10-01

The primary aim of this article is to provide an overview of perfluoroalkyl and polyfluoroalkyl substances (PFASs) detected in the environment, wildlife, and humans, and recommend clear, specific, and descriptive terminology, names, and acronyms for PFASs. The overarching objective is to unify and harmonize communication on PFASs by offering terminology for use by the global scientific, regulatory, and industrial communities. A particular emphasis is placed on long-chain perfluoroalkyl acids, substances related to the long-chain perfluoroalkyl acids, and substances intended as alternatives to the use of the long-chain perfluoroalkyl acids or their precursors. First, we define PFASs, classify them into various families, and recommend a pragmatic set of common names and acronyms for both the families and their individual members. Terminology related to fluorinated polymers is an important aspect of our classification. Second, we provide a brief description of the 2 main production processes, electrochemical fluorination and telomerization, used for introducing perfluoroalkyl moieties into organic compounds, and we specify the types of byproducts (isomers and homologues) likely to arise in these processes. Third, we show how the principal families of PFASs are interrelated as industrial, environmental, or metabolic precursors or transformation products of one another. We pay particular attention to those PFASs that have the potential to be converted, by abiotic or biotic environmental processes or by human metabolism, into long-chain perfluoroalkyl carboxylic or sulfonic acids, which are currently the focus of regulatory action. The Supplemental Data lists 42 families and subfamilies of PFASs and 268 selected individual compounds, providing recommended names and acronyms, and structural formulas, as well as Chemical Abstracts Service registry numbers. Copyright © 2011 SETAC.

Carbon chemistry: The high temperature syntheses and applications of nanotubes andsp-hybridized compounds

NASA Astrophysics Data System (ADS)

Mitchell, Daniel Robert

A brief introduction to carbon chemistry is given with an emphasis on the use high-temperature reactions that use carbon vapor, generated from graphite, to synthesize nano-structured materials. Laser and electric are ablation of graphite was utilized to create a variety of high carbon content materials ranging from discrete acetylenic molecules to extremely large multi-wall nanotubes. A new synthesis for large carbon nanotubes, containing 1--5 atom percent nitrogen bound into the graphite lattice, was realized by the reaction of carbon vapor, nickel/yttrium catalyst and cyanogen gas. These carbon "megatubes" were then employed as a substrate to tether a wide variety of molecules both inorganic and organic. The megatubes, in their native and derivatized states, were then assembled into simple circuits to explore their electronic transport properties. Direct fluorination was used to post-treat the surface of the multi-wall carbon nanotubes in order to alter the inherent physical and chemical properties of the tubes, as well as to serve as another route to functionalize their surfaces. Fluorine sites on the walls of the tube were allowed to react with Grignard reagents to produce nantoubes with the chosen alkyl chemically bonded to the surface. Products were characterized with techniques similar to unfluorinated tubules. Using similar carbon vaporization techniques, sp-hybridized carbon chain compounds were synthesized. Using a one-step method dicyanopolyynes were synthesized and characterized with nuclear magnetic resonance and mass spectroscopy, containing up to 8 acetylenic repeat units. A two-step method was also utilized to create polyynes terminated with trifluoromethyl or nitrile radicals generated in a capacitively coupled radio frequency glow plasma discharge. A partial characterization of these products was accomplished with nuclear magnetic resonance, mass, and infrared spectroscopy techniques.

Perfluoroalkyl and Polyfluoroalkyl Substances in the Environment: Terminology, Classification, and Origins

PubMed Central

Buck, Robert C; Franklin, James; Berger, Urs; Conder, Jason M; Cousins, Ian T; de Voogt, Pim; Jensen, Allan Astrup; Kannan, Kurunthachalam; Mabury, Scott A; van Leeuwen, Stefan PJ

2011-01-01

The primary aim of this article is to provide an overview of perfluoroalkyl and polyfluoroalkyl substances (PFASs) detected in the environment, wildlife, and humans, and recommend clear, specific, and descriptive terminology, names, and acronyms for PFASs. The overarching objective is to unify and harmonize communication on PFASs by offering terminology for use by the global scientific, regulatory, and industrial communities. A particular emphasis is placed on long-chain perfluoroalkyl acids, substances related to the long-chain perfluoroalkyl acids, and substances intended as alternatives to the use of the long-chain perfluoroalkyl acids or their precursors. First, we define PFASs, classify them into various families, and recommend a pragmatic set of common names and acronyms for both the families and their individual members. Terminology related to fluorinated polymers is an important aspect of our classification. Second, we provide a brief description of the 2 main production processes, electrochemical fluorination and telomerization, used for introducing perfluoroalkyl moieties into organic compounds, and we specify the types of byproducts (isomers and homologues) likely to arise in these processes. Third, we show how the principal families of PFASs are interrelated as industrial, environmental, or metabolic precursors or transformation products of one another. We pay particular attention to those PFASs that have the potential to be converted, by abiotic or biotic environmental processes or by human metabolism, into long-chain perfluoroalkyl carboxylic or sulfonic acids, which are currently the focus of regulatory action. The Supplemental Data lists 42 families and subfamilies of PFASs and 268 selected individual compounds, providing recommended names and acronyms, and structural formulas, as well as Chemical Abstracts Service registry numbers. Integr Environ Assess Manag 2011;7:513–541. © 2011 SETAC PMID:21793199

Preparation and Surface Property of Fluoroalkyl End-Capped Vinyltrimethoxysilane Oligomer/Talc Composite-Encapsulated Organic Compounds: Application for the Separation of Oil and Water.

PubMed

Oikawa, Yuri; Saito, Tomoya; Yamada, Satoshi; Sugiya, Masashi; Sawada, Hideo

2015-07-01

Fluoroalkyl end-capped vinyltrimethoxysilane oligomer [R(F)-(CH2-CHSi(OMe)3)n-R(F); n = 2, 3; R(F) = CF(CF3)OC3F7 (R(F)-VM oligomer)] can undergo the sol-gel reaction in the presence of talc particles under alkaline conditions at room temperature to provide the corresponding fluorinated oligomeric silica/talc nanocomposites (RF-VM-SiO2/Talc). A variety of guest molecules such as 2-hydroxy-4-methoxybenzophenone (HMB), bisphenol A (BPA), bisphenol AF, 3-(hydroxysilyl)-1-propanesulfonic acid (THSP), and perfluoro-2-methyl-3-oxahexanoic acid (R(F)-COOH) are effectively encapsulated into the R(F)-VM-SiO2/Talc composite cores to afford the corresponding fluorinated nanocomposites-encapsulated these guest molecules. The R(F)-VM-SiO2/Talc composites encapsulated low molecular weight aromatic compounds such as HMB and BPA can exhibit a superoleophilic-superhydrophobic characteristic on the surfaces; however, the R(F)-VM-SiO2/Talc composite-encapsulated THSP and R(F)-COOH exhibit a superoleophobic-superhydrophilic characteristic on the modified surfaces. In these nanocomposites, the R(F)-VM-SiO2/Talc/THSP composites are applicable to the surface modification of polyester fabric, and the modified polyester fabric possessing a superoleophobic-superhydrophilic characteristic on the surface can be used for the membrane for oil (dodecane)/water separation. In addition, the R(F)-VM-SiO2/Talc composites-encapsulated micrometer-size controlled cross-linked polystyrene particles can be also prepared under similar conditions, and the obtained composite white-colored particle powders are applied to the packing material for the column chromatography to separate water-in-oil (W/O) emulsion.

Fluorinated porphyrinoids as efficient platforms for new photonic materials, sensors, and therapeutics.

PubMed

Bhupathiraju, N V S Dinesh K; Rizvi, Waqar; Batteas, James D; Drain, Charles Michael

2016-01-14

Porphyrinoids are robust heterocyclic dyes studied extensively for their applications in medicine and as photonic materials because of their tunable photophysical properties, diverse means of modifying the periphery, and the ability to chelate most transition metals. Commercial applications include their use as phthalocyanine dyes in optical discs, porphyrins in photodynamic therapy, and as oxygen sensors. Most applications of these dyes require exocyclic moieties to improve solubility, target diseases, modulate photophysical properties, or direct the self-organization into architectures with desired photonic properties. The synthesis of the porphyrinoid depends on the desired application, but the de novo synthesis often involves several steps, is time consuming, and results in low isolated yields. Thus, the application of core porphyrinoid platforms that can be rapidly and efficiently modified to evaluate new molecular architectures allows researchers to focus on the design concepts rather than the synthesis methods, and opens porphyrinoid chemistry to a broader scientific community. We have focused on several widely available, commercially viable porphyrinoids as platforms: meso-perfluorophenylporphyrin, perfluorophthalocyanine, and meso-perfluorophenylcorrole. The perfluorophenylporphyrin is readily converted to the chlorin, bacteriochlorin, and isobacteriochlorin. Derivatives of all six of these core platforms can be efficiently and controllably made via mild nucleophilic aromatic substitution reactions using primary S, N, and O nucleophiles bearing a wide variety of functional groups. The remaining fluoro groups enhance the photo and oxidative stability of the dyes and can serve as spectroscopic signatures to characterize the compounds or in imaging applications using (19)F NMR. This review provides an overview of the chemistry of fluorinated porphyrinoids that are being used as a platform to create libraries of photo-active compounds for applications in medicine and materials.

Biodegradation of pentafluorosulfanyl-substituted aminophenol in Pseudomonas spp.

PubMed

Saccomanno, Marta; Hussain, Sabir; O'Connor, Neil K; Beier, Petr; Somlyay, Mate; Konrat, Robert; Murphy, Cormac D

2018-06-01

The pentafluorosulfanyl (SF 5 -) substituent conveys properties that are beneficial to drugs and agrochemicals. As synthetic methodologies improve the number of compounds containing this group will expand and these chemicals may be viewed as emerging pollutants. As many microorganisms can degrade aromatic xenobiotics, we investigated the catabolism of SF 5 -substituted aminophenols by bacteria and found that some Pseudomonas spp. can utilise these compounds as sole carbon and energy sources. GC-MS analysis of the culture supernatants from cultures grown in 5-(pentafluorosulfanyl) 2-aminophenol demonstrated the presence of the N-acetylated derivative of the starting substrate and 4-(pentafluorosulfanyl)catechol. Biotransformation experiments with re-suspended cells were also conducted and fluorine-19 NMR analyses of the organic extract and aqueous fraction from suspended cell experiments revealed new resonances of SF 5 -substituted intermediates. Supplementation of suspended cell cultures with yeast extract dramatically improved the degradation of the substrate as well as the release of fluoride ion. 4-(Pentafluorosulfanyl)catechol was shown to be a shunt metabolite and toxic to some of the bacteria. This is the first study to demonstrate that microorganisms can biodegrade SF 5 -substituted aromatic compounds releasing fluoride ion, and biotransform them generating a toxic metabolite.

Effects of (Oxy-)Fluorination on Various High-Performance Yarns.

PubMed

Kruppke, Iris; Bartusch, Matthias; Hickmann, Rico; Hund, Rolf-Dieter; Cherif, Chokri

2016-08-26

In this work, typical high-performance yarns are oxy-fluorinated, such as carbon fibers, ultra-high-molecular-weight polyethylene, poly(p-phenylene sulfide) and poly(p-phenylene terephthalamide). The focus is on the property changes of the fiber surface, especially the wetting behavior, structure and chemical composition. Therefore, contact angle, XPS and tensile strength measurements are performed on treated and untreated fibers, while SEM is utilized to evaluate the surface structure. Different results for the fiber materials are observed. While polyethylene exhibits a relevant impact on both surface and bulk properties, polyphenylene terephthalamide and polyphenylene sulfide are only affected slightly by (oxy-)fluorination. The wetting of carbon fiber needs higher treatment intensities, but in contrast to the organic fibers, even its textile-physical properties are enhanced by the treatment. Based on these findings, the capability of (oxy-)fluorination to improve the adhesion of textiles in fiber-reinforced composite materials can be derived.

Synthesis and characterization of UV-absorbing fluorine-silicone acrylic resin polymer

NASA Astrophysics Data System (ADS)

Lei, Huibin; He, Deliang; Guo, Yanni; Tang, Yining; Huang, Houqiang

2018-06-01

A series of UV-absorbing fluorine-silicone acrylic resin polymers containing different amount of UV-absorbent were successfully prepared by solution polymerization, with 2-[3-(2H-Benzotriazol-2-yl)-4-hydroxyphenyl] ethyl methacrylate (BHEM), vinyltrimethoxysilane (VTMS) and hexafluorobutyl methacrylate (HFMA) as modifying monomers. The acrylic polymers and the coatings thereof were characterized by Fourier transform infrared spectrum (FT-IR), X-ray photoelectron spectroscopy (XPS), Ultraviolet-visible (UV-vis) absorption spectrum, thermogravimetric analysis (TGA), water contact angle (CA) and Xenon lamp artificial accelerated aging tests. Results indicated that the resin exhibited high UV absorption performance as well as good thermal stability. The hydrophobicity of the coatings was of great improvement because of the bonded fluorine and silicone. Meanwhile, the weather-resistance was promoted through preferably colligating the protective effects of BHEM, organic fluorine and silicone. Also, a fitting formula about the weatherability with the BMHE content was tentatively proposed.

40 CFR 60.201 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

...-Process Phosphoric Acid Plants § 60.201 Definitions. As used in this subpart, all terms not defined herein... acid plant means any facility manufacturing phosphoric acid by reacting phosphate rock and acid. (b) Total fluorides means elemental fluorine and all fluoride compounds as measured by reference methods...

40 CFR 60.201 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

...-Process Phosphoric Acid Plants § 60.201 Definitions. As used in this subpart, all terms not defined herein... acid plant means any facility manufacturing phosphoric acid by reacting phosphate rock and acid. (b) Total fluorides means elemental fluorine and all fluoride compounds as measured by reference methods...

40 CFR 60.201 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

...-Process Phosphoric Acid Plants § 60.201 Definitions. As used in this subpart, all terms not defined herein... acid plant means any facility manufacturing phosphoric acid by reacting phosphate rock and acid. (b) Total fluorides means elemental fluorine and all fluoride compounds as measured by reference methods...

40 CFR 60.201 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

...-Process Phosphoric Acid Plants § 60.201 Definitions. As used in this subpart, all terms not defined herein... acid plant means any facility manufacturing phosphoric acid by reacting phosphate rock and acid. (b) Total fluorides means elemental fluorine and all fluoride compounds as measured by reference methods...

40 CFR 60.201 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-Process Phosphoric Acid Plants § 60.201 Definitions. As used in this subpart, all terms not defined herein... acid plant means any facility manufacturing phosphoric acid by reacting phosphate rock and acid. (b) Total fluorides means elemental fluorine and all fluoride compounds as measured by reference methods...

Biocatalytic trifluoromethylation of unprotected phenols

NASA Astrophysics Data System (ADS)

Simon, Robert C.; Busto, Eduardo; Richter, Nina; Resch, Verena; Houk, Kendall N.; Kroutil, Wolfgang

2016-11-01

Organofluorine compounds have become important building blocks for a broad range of advanced materials, polymers, agrochemicals, and increasingly for pharmaceuticals. Despite tremendous progress within the area of fluorination chemistry, methods for the direct introduction of fluoroalkyl-groups into organic molecules without prefunctionalization are still highly desired. Here we present a concept for the introduction of the trifluoromethyl group into unprotected phenols by employing a biocatalyst (laccase), tBuOOH, and either the Langlois' reagent or Baran's zinc sulfinate. The method relies on the recombination of two radical species, namely, the phenol radical cation generated directly by the laccase and the CF3-radical. Various functional groups such as ketone, ester, aldehyde, ether and nitrile are tolerated. This laccase-catalysed trifluoromethylation proceeds under mild conditions and allows accessing trifluoromethyl-substituted phenols that were not available by classical methods.

The Influence of Fluorination on Nano-Scale Phase Separation and Photovoltaic Performance of Small Molecular/PC71BM Blends

PubMed Central

Lu, Zhen; Liu, Wen; Li, Jingjing; Fang, Tao; Li, Wanning; Zhang, Jicheng; Feng, Feng; Li, Wenhua

2016-01-01

To investigate the fluorination influence on the photovoltaic performance of small molecular based organic solar cells (OSCs), six small molecules based on 2,1,3-benzothiadiazole (BT), and diketopyrrolopyrrole (DPP) as core and fluorinated phenyl (DFP) and triphenyl amine (TPA) as different terminal units (DFP-BT-DFP, DFP-BT-TPA, TPA-BT-TPA, DFP-DPP-DFP, DFP-DPP-TPA, and TPA-DPP-TPA) were synthesized. With one or two fluorinated phenyl as the end group(s), HOMO level of BT and DPP based small molecular donors were gradually decreased, inducing high open circuit voltage for fluorinated phenyl based OSCs. DFP-BT-TPA and DFP-DPP-TPA based blend films both displayed stronger nano-scale aggregation in comparison to TPA-BT-TPA and TPA-DPP-TPA, respectively, which would also lead to higher hole motilities in devices. Ultimately, improved power conversion efficiency (PCE) of 2.17% and 1.22% was acquired for DFP-BT-TPA and DFP-DPP-TPA based devices, respectively. These results demonstrated that the nano-scale aggregation size of small molecules in photovoltaic devices could be significantly enhanced by introducing a fluorine atom at the donor unit of small molecules, which will provide understanding about the relationship of chemical structure and nano-scale phase separation in OSCs. PMID:28335208

Positron emission tomography (PET) imaging with 18F-based radiotracers

PubMed Central

Alauddin, Mian M

2012-01-01

Positron Emission Tomography (PET) is a nuclear medicine imaging technique that is widely used in early detection and treatment follow up of many diseases, including cancer. This modality requires positron-emitting isotope labeled biomolecules, which are synthesized prior to perform imaging studies. Fluorine-18 is one of the several isotopes of fluorine that is routinely used in radiolabeling of biomolecules for PET; because of its positron emitting property and favorable half-life of 109.8 min. The biologically active molecule most commonly used for PET is 2-deoxy-2-18F-fluoro-β-D-glucose (18F-FDG), an analogue of glucose, for early detection of tumors. The concentrations of tracer accumulation (PET image) demonstrate the metabolic activity of tissues in terms of regional glucose metabolism and accumulation. Other tracers are also used in PET to image the tissue concentration. In this review, information on fluorination and radiofluorination reactions, radiofluorinating agents, and radiolabeling of various compounds and their application in PET imaging is presented. PMID:23133802

Reverse saturable absorption (RSA) in fluorinated iridium derivatives

NASA Astrophysics Data System (ADS)

Ferry, Michael J.; O'Donnell, Ryan M.; Bambha, Neal; Ensley, Trenton R.; Shensky, William M.; Shi, Jianmin

2017-08-01

The photophysical properties of cyclometallated iridium compounds are beneficial for nonlinear optical (NLO) applications, such as the design of reverse saturable absorption (RSA) materials. We report on the NLO characterization of a family of compounds of the form [Ir(pbt)2(LX)], where pbt is 2-phenylbenzothiazole and LX is a beta-diketonate ligand. In particular, we investigate the effects of trifluoromethylation on compound solubility and photophysics compared to the parent acetylacetonate (acac) version. The NLO properties, such as the singlet and triplet excited-state cross sections, of these compounds were measured using the Z-scan technique. The excited-state lifetimes were determined from visible transient absorption spectroscopy.

Compositions and methods related to serotonin 5-HT1A receptors

DOEpatents

Mukherjee, Jogeshwar; Saigal, Neil

2010-06-08

Contemplated substituted arylpiperazinyl compounds, and most preferably ¹⁸F-Mefway, exhibit desirable in vitro and in vivo binding characteristics to the 5-HT1A receptor. Among other advantageous parameters, contemplated compounds retain high binding affinity, display optimal lipophilicity, and are radiolabeled efficiently with ¹⁸F-fluorine in a single step. Still further, contemplated compounds exhibit high target to non-target ratios in receptor-rich regions both in vitro and in vivo, and selected compounds can be effectively and sensitively displaced by serotonin, thus providing a quantitative tool for measuring 5-HT1A receptors and serotonin concentration changes in the living brain.

Compositions and methods related to serotonin 5-HT1A receptors

DOEpatents

Mukherjee, Jogeshwar [Irvine, CA; Saigal, Neil [Fresno, CA; Saigal, legal representative, Harsh

2012-09-25

Contemplated substituted arylpiperazinyl compounds, and most preferably .sup.18F-Mefway, exhibit desirable in vitro and in vivo binding characteristics to the 5-HT1A receptor. Among other advantageous parameters, contemplated compounds retain high binding affinity, display optimal lipophilicity, and are radiolabeled efficiently with .sup.18F-fluorine in a single step. Still further, contemplated compounds exhibit high target to non-target ratios in receptor-rich regions both in vitro and in vivo, and selected compounds can be effectively and sensitively displaced by serotonin, thus providing a quantitative tool for measuring 5-HT1A receptors and serotonin concentration changes in the living brain.

Compositions and methods related to serotonin 5-HT1A receptors

DOEpatents

Mukherjee, Jogeshwar; Saigal, Neil; Saigal, legal representative, Harsh

2012-09-25

Contemplated substituted arylpiperazinyl compounds, and most preferably ¹⁸F-Mefway, exhibit desirable in vitro and in vivo binding characteristics to the 5-HT1A receptor. Among other advantageous parameters, contemplated compounds retain high binding affinity, display optimal lipophilicity, and are radiolabeled efficiently with ¹⁸F-fluorine in a single step. Still further, contemplated compounds exhibit high target to non-target ratios in receptor-rich regions both in vitro and in vivo, and selected compounds can be effectively and sensitively displaced by serotonin, thus providing a quantitative tool for measuring 5-HT1A receptors and serotonin concentration changes in the living brain.

Synthesis of methylene- and difluoromethylenephosphonate analogues of uridine-4-phosphate and 3-deazauridine-4-phosphate.

PubMed

Taylor, Scott D; Mirzaei, Farzad; Sharifi, Ali; Bearne, Stephen L

2006-12-08

Cytidine triphosphate synthetase (CTPS) catalyzes the formation of cytidine triphosphate from glutamine, uridine-5'-triphosphate (UTP), and adenosine-5'-triphosphate. Inhibitors of CTPS are of interest because of their potential as therapeutic agents. One approach to potent enzyme inhibitors is to use analogues of high energy intermediates formed during the reaction. The CTPS reaction proceeds via the high energy intermediate UTP-4-phosphate (UTP-4-P). Four novel analogues of uridine-4-phosphate (U-4-P) and 3-deazauridine-4-phosphate (3-deazaU-4-P) were synthesized in which the labile phosphate ester oxygen was replaced with a methylene and difluoromethylene group. The methylene analogue of U-4-P, compound 1, was prepared by a reaction of the sodium salt of tert-butyl diethylphosphonoacetate with protected, 4-O-activated uridine followed by acetate deprotection and decarboxylation. It was found that this compound undergoes relatively facile dephosphonylation presumably via a metaphosphate intermediate. The difluoromethylene derivative, compound 2, was prepared by electrophilic fluorination of protected 1. This compound was stable and did not undergo dephosphonylation. Synthesis of the methylene analogue of 3-deazaU-4-P, compound 3, was achieved by ribosylation of protected 4-(phosphonomethyl)-2-hydroxypyridine. Electrophilic fluorination was also employed in the preparation of protected 4-(phosphonodifluoromethyl)-2-hydroxypyridine which was used as the key building block in the synthesis of difluoro derivative 4. These compounds represent the first examples of a nucleoside in which the base has been chemically modified with a methylene or difluormethylenephosphonate group.

Colorless polyimide/organoclay nanocomposite substrates for flexible organic light-emitting devices.

PubMed

Kim, Jin-Hoe; Choi, Myeon-Chon; Kim, Hwajeong; Kim, Youngkyoo; Chang, Jin-Hae; Han, Mijeong; Kim, Il; Ha, Chang-Sik

2010-01-01

We report the preparation and application of indium tin oxide (ITO) coated fluorine-containing polyimide/organoclay nanocomposite substrate. Fluorine-containing polyimide/organoclay nanocomposite films were prepared through thermal imidization of poly(amic acid)/organoclay mixture films, whilst on which ITO thin films were coated on the films using a radio-frequency planar magnetron sputtering by varying the substrate temperature and the ITO thickness. Finally the ITO coated fluorine-containing polyimide/organoclay nanocomposite substrate was employed to make flexible organic light-emitting devices (OLED). Results showed that the lower sheet resistance was achieved when the substrate temperature was high and the ITO film was thick even though the optical transmittance was slightly lowered as the thickness increased. approximately 10 nm width ITO nanorods were found for all samples but the size of clusters with the nanorods was generally increased with the substrate temperature and the thickness. The flexible OLED made using the present substrate was quite stable even when the device was extremely bended.

Emission factors of air toxics from semiconductor manufacturing in Korea.

PubMed

Eom, Yun-Sung; Hong, Ji-Hyung; Lee, Suk-Jo; Lee, Eun-Jung; Cha, Jun-Seok; Lee, Dae-Gyun; Bang, Sun-Ae

2006-11-01

The development of local, accurate emission factors is very important for the estimation of reliable national emissions and air quality management. For that, this study is performed for pollutants released to the atmosphere with source-specific emission tests from the semiconductor manufacturing industry. The semiconductor manufacturing industry is one of the major sources of air toxics or hazardous air pollutants (HAPs); thus, understanding the emission characteristics of the emission source is a very important factor in the development of a control strategy. However, in Korea, there is a general lack of information available on air emissions from the semiconductor industry. The major emission sources of air toxics examined from the semiconductor manufacturing industry were wet chemical stations, coating applications, gaseous operations, photolithography, and miscellaneous devices in the wafer fabrication and semiconductor packaging processes. In this study, analyses of emission characteristics, and the estimations of emission data and factors for air toxics, such as acids, bases, heavy metals, and volatile organic compounds from the semiconductor manufacturing process have been performed. The concentration of hydrogen chloride from the packaging process was the highest among all of the processes. In addition, the emission factor of total volatile organic compounds (TVOCs) for the packaging process was higher than that of the wafer fabrication process. Emission factors estimated in this study were compared with those of Taiwan for evaluation, and they were found to be of similar level in the case of TVOCs and fluorine compounds.

Development of a predictive model for lead, cadmium and fluorine soil-water partition coefficients using sparse multiple linear regression analysis.

PubMed

Nakamura, Kengo; Yasutaka, Tetsuo; Kuwatani, Tatsu; Komai, Takeshi

2017-11-01

In this study, we applied sparse multiple linear regression (SMLR) analysis to clarify the relationships between soil properties and adsorption characteristics for a range of soils across Japan and identify easily-obtained physical and chemical soil properties that could be used to predict K and n values of cadmium, lead and fluorine. A model was first constructed that can easily predict the K and n values from nine soil parameters (pH, cation exchange capacity, specific surface area, total carbon, soil organic matter from loss on ignition and water holding capacity, the ratio of sand, silt and clay). The K and n values of cadmium, lead and fluorine of 17 soil samples were used to verify the SMLR models by the root mean square error values obtained from 512 combinations of soil parameters. The SMLR analysis indicated that fluorine adsorption to soil may be associated with organic matter, whereas cadmium or lead adsorption to soil is more likely to be influenced by soil pH, IL. We found that an accurate K value can be predicted from more than three soil parameters for most soils. Approximately 65% of the predicted values were between 33 and 300% of their measured values for the K value; 76% of the predicted values were within ±30% of their measured values for the n value. Our findings suggest that adsorption properties of lead, cadmium and fluorine to soil can be predicted from the soil physical and chemical properties using the presented models. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enzymatic Halogenation and Dehalogenation Reactions: Pervasive and Mechanistically Diverse.

PubMed

Agarwal, Vinayak; Miles, Zachary D; Winter, Jaclyn M; Eustáquio, Alessandra S; El Gamal, Abrahim A; Moore, Bradley S

2017-04-26

Naturally produced halogenated compounds are ubiquitous across all domains of life where they perform a multitude of biological functions and adopt a diversity of chemical structures. Accordingly, a diverse collection of enzyme catalysts to install and remove halogens from organic scaffolds has evolved in nature. Accounting for the different chemical properties of the four halogen atoms (fluorine, chlorine, bromine, and iodine) and the diversity and chemical reactivity of their organic substrates, enzymes performing biosynthetic and degradative halogenation chemistry utilize numerous mechanistic strategies involving oxidation, reduction, and substitution. Biosynthetic halogenation reactions range from simple aromatic substitutions to stereoselective C-H functionalizations on remote carbon centers and can initiate the formation of simple to complex ring structures. Dehalogenating enzymes, on the other hand, are best known for removing halogen atoms from man-made organohalogens, yet also function naturally, albeit rarely, in metabolic pathways. This review details the scope and mechanism of nature's halogenation and dehalogenation enzymatic strategies, highlights gaps in our understanding, and posits where new advances in the field might arise in the near future.

Optimum working fluids for solar powered Rankine cycle cooling of buildings

NASA Astrophysics Data System (ADS)

Wali, E.

1980-01-01

A number of fluids were screened for their operational reliability and thermal stability as working fluids for domestic solar Rankine cycle cooling. The results indicate that the halogenated compound R-113, followed by the fluorinated compound FC-88, is best suited for safe Rankine cycle operation. Further dynamic investigations are, however, needed to study the thermal stability of these fluids in the presence and absence of lubricants in copper, steel, and alloy conduits

Different binding mechanisms of neutral and anionic poly-/perfluorinated chemicals to human transthyretin revealed by In silico models.

PubMed

Yang, Xianhai; Lyakurwa, Felichesmi; Xie, Hongbin; Chen, Jingwen; Li, Xuehua; Qiao, Xianliang; Cai, Xiyun

2017-09-01

Chemical forms-dependent binding interactions between phenolic compounds and human transthyretin (hTTR) have been elaborated previously. However, it is not known whether the binding interactions between ionizable halogenated alphatic compounds and hTTR also have the same manner. In this study, poly-/perfluorinated chemicals (PFCs) were selected as model compounds and molecular dynamic simulation was performed to investigate the binding mechanisms between PFCs and hTTR. Results show the binding interactions between the halogenated aliphatic compounds and hTTR are related to the chemical forms. The ionized groups of PFCs can form electrostatic interactions with the -NH + 3 groups of Lys 15 residues in hTTR and form hydrogen bonds with the residues of hTTR. By analyzing the molecular orbital energies of PFCs, we also found that the anionic groups (nucleophile) in PFCs could form electron donor - acceptor interactions with the -NH + 3 groups (electrophile) in Lys 15. The aforementioned orientational interactions make the ionized groups of the PFCs point toward the entry port of the binding site. The roles of fluorine atoms in the binding interactions were also explored. The fluorine atoms can influence the binding interactions via inductive effects. Appropriate molecular descriptors were selected to characterize these interactions, and two quantitative structure-activity relationship models were developed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Antimicrobial Activity and Urease Inhibition of Schiff Bases Derived from Isoniazid and Fluorinated Benzaldehydes and of Their Copper(II) Complexes.

PubMed

Habala, Ladislav; Varényi, Samuel; Bilková, Andrea; Herich, Peter; Valentová, Jindra; Kožíšek, Jozef; Devínsky, Ferdinand

2016-12-17

In order to evaluate the influence of substitution on biological properties of Schiff bases and their metal complexes, a series of differently substituted fluorine-containing Schiff bases starting from the drug isoniazid (isonicotinylhydrazide) were prepared and their structures were established by single-crystal X-ray diffraction. Also, four copper(II) complexes of these Schiff bases were synthesized. The prepared compounds were evaluated for their antimicrobial activity and urease inhibition. Two of the Schiff bases exerted activity against C. albicans . All copper(II) complexes showed excellent inhibitory properties against jack bean urease, considerably better than that of the standard inhibitor acetohydroxamic acid.

Effects of Aromatic Fluorine Substitution on Protonated Neurotransmitters: The Case of 2-Phenylethylamine.

PubMed

Schütz, Markus; Bouchet, Aude; Chiavarino, Barbara; Crestoni, Maria Elisa; Fornarini, Simonetta; Dopfer, Otto

2016-06-06

Fluorination of pharmaceutical compounds is a common tool to modulate their physiochemical properties. We determine the effects of site-specific aromatic fluorine substitution on the geometric, energetic, vibrational, and electronic properties of the protonated neurotransmitter 2-phenylethylamine (xF-H(+) PEA, x=ortho, meta, para) by infrared multiphoton photodissociation (IRMPD) in the fingerprint range (600-1750 cm(-1) ) and quantum chemical calculations at the B3LYP-D3/aug-cc-pVTZ level. The IRMPD spectra of all ions are assigned to their folded gauche conformers stabilized by intramolecular NH(+) ⋅⋅⋅π hydrogen bonds (H-bonds) between the protonated amino group and the aromatic ring. H→F substitution reduces the symmetry and allows for additional NH(+) ⋅⋅⋅F interactions in oF-H(+) PEA, leading to three distinct gauche conformers. In comparison to oF-H(+) PEA, the fluorination effects on the energy landscape (energy ordering and isomerization barriers) in pF-H(+) PEA and mF-H(+) PEA with one and two gauche conformers are less pronounced. The strengths of the intramolecular NH(+) ⋅⋅⋅F and NH(+) ⋅⋅⋅π bonds are analyzed by the noncovalent interaction (NCI) method. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fluorinated organic compounds in an eastern Arctic marine food web.

PubMed

Tomy, Gregg T; Budakowski, Wes; Halldorson, Thor; Helm, Paul A; Stern, Gary A; Friesen, Ken; Pepper, Karen; Tittlemier, Sheryl A; Fisk, Aaron T

2004-12-15

An eastern Arctic marine food web was analyzed for perfluorooctanesulfonate (PFOS, C8F17SO3-), perfluorooctanoate (PFOA, C7F15COO-), perfluorooctane sulfonamide (PFOSA, C8F17SO2NH2), and N-ethylperfluorooctane sulfonamide (N-EtPFOSA, C8F17SO2NHCH2CH3) to examine the extent of bioaccumulation. PFOS was detected in all species analyzed, and mean concentrations ranged from 0.28 +/- 0.09 ng/g (arithmetic mean +/- 1 standard error, wet wt, whole body) in clams (Mya truncata) to 20.2 +/- 3.9 ng/g (wet wt, liver) in glaucous gulls (Larus hyperboreus). PFOA was detected in approximately 40% of the samples analyzed at concentrations generally smaller than those found for PFOS; the greatest concentrations were observed in zooplankton (2.6 +/- 0.3 ng/g, wet wt). N-EtPFOSA was detected in all species except redfish with mean concentrations ranging from 0.39 +/- 0.07 ng/g (wet wt) in mixed zooplankton to 92.8 +/- 41.9 ng/g (wet wt) in Arctic cod (Boreogadus saida). This is the first report of N-EtPFOSA in Arctic biota. PFOSA was only detected in livers of beluga (Delphinapterus leucas) (20.9 +/- 7.9 ng/g, wet wt) and narwhal (Monodon monoceros) (6.2 +/- 2.3 ng/g, wet wt), suggesting that N-EtPFOSA and other PFOSA-type precursors are likely present but are being biotransformed to PFOSA. A positive linear relationship was found between PFOS concentrations (wet wt) and trophic level (TL), based on delta15N values, (r2 = 0.51, p < 0.0001) resulting in a trophic magnification factor of 3.1. TL-corrected biomagnification factor estimates for PFOS ranged from 0.4 to 9. Both results indicate that PFOS biomagnifies in the Arctic marine food web when liver concentrations of PFOS are used for seabirds and marine mammals. However, transformation of N-EtPFOSA and PFOSA and potential other perfluorinated compounds to PFOS may contribute to PFOS levels in marine mammals and may inflate estimated biomagnification values. None of the other fluorinated compounds (N-EtPFOSA, PFOSA, and PFOA) were found to have a significant relationship with TL, but BMF(TL) values of these compounds were often >1, suggesting potential for these compounds to biomagnify. The presence of perfluorinated compounds in seabirds and mammals provides evidence that trophic transfer is an important exposure route of these chemicals to Arctic biota.

Control of indium tin oxide anode work function modified using Langmuir-Blodgett monolayer for high-efficiency organic photovoltaics

NASA Astrophysics Data System (ADS)

Yokokura, Yuya; Dogase, Tomomichi; Shinbo, Tatsuki; Nakayashiki, Yuya; Takagi, Yusuke; Ueda, Kazuyoshi; Sarangerel, Khayankhyarvaa; Delgertsetseg, Byambasuren; Ganzorig, Chimed; Sakomura, Masaru

2017-08-01

The use of Langmuir-Blodgett (LB) monolayers to modify the indium tin oxide (ITO) work function and thus improve the performance of zinc phthalocyanine (ZnPc)/fullerene (C60)-based and boron subphthalocyanine chloride (SubPc)/C60-based small molecule organic photovoltaic devices (OPVs) was examined. In general, LB precursor compounds contain one or more long alkyl chain substituents that can act as spacers to prevent electrical contact with adjoining electrode surfaces. As one example of such a compound, arachidic acid (CH3(CH2)18COOH) was inserted in the forms of one-layer, three-layer or five-layer LB films between the anode ITO layer and the p-type layer in ZnPc-C60-based OPVs to investigate the effects of the long alkyl chain group when it acts as an electrically insulating spacer. The short-circuit current density (Jsc) values of the OPVs with the three- and five-layer inserts (1.78 mA.cm-2 and 0.61 mA.cm-2, respectively) were reduced dramatically, whereas the Jsc value for the OPV with the single-layer insertion (2.88 mA.cm-2) was comparable to that of the OPV without any insert (3.14 mA.cm-2). The ITO work function was shifted positively by LB deposition of a surfactant compound, C9F19C2H4-O-C2H4-COOH (PFECA), which contained a fluorinated head group. This positive effect was maintained even after formation of an upper p-type organic layer. The Jsc and open-circuit voltage (Voc) of the SubPc-C60-based OPV with the LB-modified ITO layers were effectively enhanced. As a result, a 42% increase in device efficiency was achieved.

Toxic Hazards Research Unit Annual Technical Report: 1985

DTIC Science & Technology

1985-09-01

varnish makers’ and painters’ naphtha, Toxicol. Appl. Pharmacol., 32:263-281. Carpenter, C. P.. E. R. Kinkead, D. L. Geary, L. J. Sullivan, Jr., and J...and Pharmacology of Inorganic and Fluorine Contairnin Compounds, AMRL-TR-67-224, Aerospace Medical Research Laboiatory, Wright-Patterson Air Force Base

Analysis of the Hazardous Material Reutilization Facilities at SUBASE Bangor and NS San Diego

DTIC Science & Technology

1990-12-01

soprene * styrene methyl acrylate methyl methacrylate *turpentine? varnish 9 GROUP IV: OXIDES AND PEROXIDE -rORKING COMPOUNDS a) Gases b) Liquids...lead fluorine GROUP XV: POISON a GROUP XVI: OXIDIZERS .a) Solid a) Solid phosphorus red ammonium nitrate phosphorus white/, ammonium perchlorate yellow

Fluorinated tripodal receptors for potentiometric chloride detection in biological fluids.

PubMed

Pankratova, Nadezda; Cuartero, Maria; Jowett, Laura A; Howe, Ethan N W; Gale, Philip A; Bakker, Eric; Crespo, Gastón A

2018-01-15

Fluorinated tripodal compounds were recently reported to be efficient transmembrane transporters for a series of inorganic anions. In particular, this class of receptors has been shown to be suitable for the effective complexation of chloride, nitrate, bicarbonate and sulfate anions via hydrogen bonding. The potentiometric properties of urea and thiourea-based fluorinated tripodal receptors are explored here for the first time, in light of the need for reliable sensors for chloride monitoring in undiluted biological fluids. The ion selective electrode (ISE) membranes with tren-based tris-urea bis(CF 3 ) tripodal compound (ionophore I) were found to exhibit the best selectivity for chloride over major lipophilic anions such as salicylate ( [Formula: see text] ) and thiocyanate ( [Formula: see text] ). Ionophore I-based ISEs were successfully applied for chloride determination in undiluted human serum as well as artificial serum sample, the slope of the linear calibration at the relevant background of interfering ions being close to Nernstian (49.8±1.7mV). The results of potentiometric measurements were confirmed by argentometric titration. Moreover, the ionophore I-based ISE membrane was shown to exhibit a very good long-term stability of potentiometric performance over the period of 10 weeks. Nuclear magnetic resonance (NMR) titrations, potentiometric sandwich membrane experiments and density functional theory (DFT) computational studies were performed to determine the binding constants and suggest 1:1 complexation stoichiometry for the ionophore I with chloride as well as salicylate. Copyright © 2017 Elsevier B.V. All rights reserved.

Fluorinated, Sulfur-Rich, Covalent Triazine Frameworks for Enhanced Confinement of Polysulfides in Lithium-Sulfur Batteries.

PubMed

Xu, Fei; Yang, Shuhao; Jiang, Guangshen; Ye, Qian; Wei, Bingqing; Wang, Hongqiang

2017-11-01

Lithium-sulfur battery represents a promising class of energy storage technology owing to its high theoretical energy density and low cost. However, the insulating nature, shuttling of soluble polysulfides and volumetric expansion of sulfur electrodes seriously give rise to the rapid capacity fading and low utilization. In this work, these issues are significantly alleviated by both physically and chemically restricting sulfur species in fluorinated porous triazine-based frameworks (FCTF-S). One-step trimerization of perfluorinated aromatic nitrile monomers with elemental sulfur allows the simultaneous formation of fluorinated triazine-based frameworks, covalent attachment of sulfur and its homogeneous distribution within the pores. The incorporation of electronegative fluorine in frameworks provides a strong anchoring effect to suppress the dissolution and accelerate the conversion of polysulfides. Together with covalent chemical binding and physical nanopore-confinement effects, the FCTF-S demonstrates superior electrochemical performances, as compared to those of the sulfur-rich covalent triazine-based framework without fluorine (CTF-S) and porous carbon delivering only physical confinement. Our approach demonstrates the potential of regulating lithium-sulfur battery performances at a molecular scale promoted by the porous organic polymers with a flexible design.

Pd nanoparticles Supported on Cellulose as a catalyst for vanillin conversion in aqueous media.

PubMed

Li, Dan-Dan; Zhang, Jia-Wei; Cai, Chun

2018-05-17

Palladium nanoparticles were firstly anchored on modified biopolymer as an efficient catalyst for biofuel upgradation. Fluorinated compounds was grafted onto cellulose to obtain amphiphilic supports for on water reactions. Pd catalyst was prepared by straightforward deposition of metal nanoparticles on modified cellulose. The catalyst exhibited excellent catalytic activity and selectivity in hydrodeoxygenation of vanillin (a typical model compound of lignin) to 2-methoxy-4-methylphenol under atmospheric hydrogen pressure in neat water without any other additives under mild conditions.

Preparation of perfluorinated 1,2,4-oxadiazoles

NASA Technical Reports Server (NTRS)

Kratzer, R. H.; Paciorek, K. J. L.; Ito, T. I.; Rosser, R. W. (Inventor)

1982-01-01

Fluorinated alkyl or alkylether 1,2,4 oxadiazole compounds are prepared by cyclizing the corresponding alkyl or alkylether imidoyl amidoximes in vacuo or in an inert atmosphere at a temperature within the range of 40 C to 100 C. for a period of 8 to 144 hours in the presence of an acid compound which can accept ammonia to form a salt. The imidoyl amidoximes usable in this process are either polymeric or nonpolymeric. The products, when polymeric, have excellent heat, chemical and solvent resistance.

Decreased IgA+ B cells population and IgA, IgG, IgM contents of the cecal tonsil induced by dietary high fluorine in broilers.

PubMed

Liu, Juan; Cui, Hengmin; Peng, Xi; Fang, Jing; Zuo, Zhicai; Deng, Junliang; Wang, Hesong; Wu, Bangyuan; Deng, Yuanxin; Wang, Kangping

2013-05-02

Fluoride is an environmental and industrial pollutant that affects various organs in humans and animals. The cecal tonsil is an important component of the mucosal immune system and performs important and unique immune functions. In the present study, we investigated the effects of dietary high fluorine on the quantities of IgA+ B cells in the cecal tonsil by immunohistochemistry, and the immunoglobulin A (IgA), immunoglobulin G (IgG) and immunoglobulin M (IgM) contents in the cecal tonsil by ELISA. A total of 280 one-day-old avian broilers were divided into four groups and fed on a corn-soybean basal diet as control diet (fluorine 22.6 mg/kg) or the same diet supplemented with 400, 800 and 1,200 mg/kg fluorine (high fluorine groups I, II and III) in the form of sodium fluoride, respectively, throughout a 42-day experimental period. The results showed that the quantities of IgA+ B cells were lower (p < 0.05 or p < 0.01) and the IgA, IgG, and IgM contents were decreased (p < 0.05 or p < 0.01) in high fluorine groups II and III in comparison with those of control group. It was concluded that dietary fluorine, in the 800-1,200 mg/kg range, could reduce the numbers of the IgA+ B cells and immunoglobulin contents in the cecal tonsil, implying the local mucosal immune function was ultimately impacted in broilers.

Decreased IgA+ B Cells Population and IgA, IgG, IgM Contents of the Cecal Tonsil Induced by Dietary High Fluorine in Broilers

PubMed Central

Liu, Juan; Cui, Hengmin; Peng, Xi; Fang, Jing; Zuo, Zhicai; Deng, Junliang; Wang, Hesong; Wu, Bangyuan; Deng, Yuanxin; Wang, Kangping

2013-01-01

Fluoride is an environmental and industrial pollutant that affects various organs in humans and animals. The cecal tonsil is an important component of the mucosal immune system and performs important and unique immune functions. In the present study, we investigated the effects of dietary high fluorine on the quantities of IgA+ B cells in the cecal tonsil by immunohistochemistry, and the immunoglobulin A (IgA), immunoglobulin G (IgG) and immunoglobulin M (IgM) contents in the cecal tonsil by ELISA. A total of 280 one-day-old avian broilers were divided into four groups and fed on a corn-soybean basal diet as control diet (fluorine 22.6 mg/kg) or the same diet supplemented with 400, 800 and 1,200 mg/kg fluorine (high fluorine groups I, II and III) in the form of sodium fluoride, respectively, throughout a 42-day experimental period. The results showed that the quantities of IgA+ B cells were lower (p < 0.05 or p < 0.01) and the IgA, IgG, and IgM contents were decreased (p < 0.05 or p < 0.01) in high fluorine groups II and III in comparison with those of control group. It was concluded that dietary fluorine, in the 800–1,200 mg/kg range, could reduce the numbers of the IgA+ B cells and immunoglobulin contents in the cecal tonsil, implying the local mucosal immune function was ultimately impacted in broilers. PMID:23644827

Analytical techniques and method validation for the measurement of selected semivolatile and nonvolatile organofluorochemicals in air.

PubMed

Reagen, William K; Lindstrom, Kent R; Thompson, Kathy L; Flaherty, John M

2004-09-01

The widespread use of semi- and nonvolatile organofluorochemicals in industrial facilities, concern about their persistence, and relatively recent advancements in liquid chromatography/mass spectrometry (LC/MS) technology have led to the development of new analytical methods to assess potential worker exposure to airborne organofluorochemicals. Techniques were evaluated for the determination of 19 organofluorochemicals and for total fluorine in ambient air samples. Due to the potential biphasic nature of most of these fluorochemicals when airborne, Occupational Safety and Health Administration (OSHA) versatile sampler (OVS) tubes were used to simultaneously trap fluorochemical particulates and vapors from workplace air. Analytical methods were developed for OVS air samples to quantitatively analyze for total fluorine using oxygen bomb combustion/ion selective electrode and for 17 organofluorochemicals using LC/MS and gas chromatography/mass spectrometry (GC/MS). The experimental design for this validation was based on the National Institute of Occupational Safety and Health (NIOSH) Guidelines for Air Sampling and Analytical Method Development and Evaluation, with some revisions of the experimental design. The study design incorporated experiments to determine analytical recovery and stability, sampler capacity, the effect of some environmental parameters on recoveries, storage stability, limits of detection, precision, and accuracy. Fluorochemical mixtures were spiked onto each OVS tube over a range of 0.06-6 microg for each of 12 compounds analyzed by LC/MS and 0.3-30 microg for 5 compounds analyzed by GC/MS. These ranges allowed reliable quantitation at 0.001-0.1 mg/m3 in general for LC/MS analytes and 0.005-0.5 mg/m3 for GC/MS analytes when 60 L of air are sampled. The organofluorochemical exposure guideline (EG) is currently 0.1 mg/m3 for many analytes, with one exception being ammonium perfluorooctanoate (EG is 0.01 mg/m3). Total fluorine results may be used to determine if the individual compounds quantified provide a suitable mass balance of total airborne organofluorochemicals based on known fluorine content. Improvements in precision and/or recovery as well as some additional testing would be needed to meet all NIOSH validation criteria. This study provided valuable information about the accuracy of this method for organofluorochemical exposure assessment.

Biocatalytic trifluoromethylation of unprotected phenols

PubMed Central

Simon, Robert C.; Busto, Eduardo; Richter, Nina; Resch, Verena; Houk, Kendall N.; Kroutil, Wolfgang

2016-01-01

Organofluorine compounds have become important building blocks for a broad range of advanced materials, polymers, agrochemicals, and increasingly for pharmaceuticals. Despite tremendous progress within the area of fluorination chemistry, methods for the direct introduction of fluoroalkyl-groups into organic molecules without prefunctionalization are still highly desired. Here we present a concept for the introduction of the trifluoromethyl group into unprotected phenols by employing a biocatalyst (laccase), tBuOOH, and either the Langlois' reagent or Baran's zinc sulfinate. The method relies on the recombination of two radical species, namely, the phenol radical cation generated directly by the laccase and the CF3-radical. Various functional groups such as ketone, ester, aldehyde, ether and nitrile are tolerated. This laccase-catalysed trifluoromethylation proceeds under mild conditions and allows accessing trifluoromethyl-substituted phenols that were not available by classical methods. PMID:27834376

Potential Use of Passive Sampling for Environmental Monitoring of Petroleum E&P Operations

EPA Pesticide Factsheets

Traditional environmental monitoring relies on water or soil samples being taken at various time increments and sent to offsite laboratories for analysis. Reliance on grab samples generally captures limited “snapshots” of environmental contaminant concentrations, is time intensive, costly, and generates residual waste from excess sample and/or reagents used in the analysis procedures. As an alternative, we are evaluating swellable organosilica sorbents to create passive sampling systems for monitoring applications. Previous work has focused on absorption and detection of fuels, chlorinated solvents, endocrine disruptors, explosives, pesticides, fluorinated chemicals, and metals including Ba, Sr, Hg, Pb, Fe, Cu, and Zn. The advantages of swellable organosilica are that the material cancapture target compounds for an extended periods of time, does not absorb natural organic matter, and resists biofilm formation since the sorbent possesses an animated surface morphology.

The Effects of Ion-Assisted Deposition on the Mechanical, Physical, Chemical and Optical Properties of Magnesium Fluoride Thin Films.

NASA Astrophysics Data System (ADS)

Kennemore, Charles Milton, III

1992-01-01

This dissertation investigates the results of ion assisted deposition (IAD) on various properties of magnesium fluoride thin films deposited on room temperature substrates. MgF_2 films deposited in this manner have increased abrasion resistance and increased adhesion comparable to that found in films deposited at the usual substrate temperature of approximately 300 ^circC. IAD tends to drive the normal high tensile stress of non-IAD films to a more compressive state thereby reducing the overall stress. The IAD MgF _2 films have a higher index of refraction than non-IAD films, as high as 1.41, and the ultraviolet absorption edge in shifted to longer wavelengths beginning about 350 nm but no detectable absorption at visible wavelengths is seen in the films deposited with less than 250 eV bombardment energies. However, at higher IAD energies beginning at approximately 600 eV an absorption band is present in the red end of the visible spectrum making low energy bombardment the parameter of choice. Transmission electron microscopy and X-ray diffraction studies show that the IAD films have a more amorphous-like structure with fewer and smaller crystallites than non-IAD films deposited on either heated or unheated substrates. Rutherford backscattering spectroscopy (RBS) shows the bombarded films have fluorine depletion that roughly scales with the energy of bombardment with F:Mg ratios as low as 1.69 being found. Bombardment by fluorinated compounds, specifically C_2 F_6 and SF_6 , limit this depletion and in some instances super fluorinate the resulting compound. Additionally, RBS shows that IAD introduces a significant amount of oxygen throughout the film that is unaccountable as water take-up. X-ray photoelectron spectroscopy (XPS) indicates the presence of two compounds of oxygen that are attributed to MgO and Mg(OH)_2 or some oxy-fluoride complex similar to them and it is the introduction of these compounds which provide for the changes in the properties of IAD MgF_2 as compared to non-IAD films of MgF_2.

Fluorine-19 MRI Contrast Agents for Cell Tracking and Lung Imaging

PubMed Central

Fox, Matthew S.; Gaudet, Jeffrey M.; Foster, Paula J.

2015-01-01

Fluorine-19 (19F)-based contrast agents for magnetic resonance imaging stand to revolutionize imaging-based research and clinical trials in several fields of medical intervention. First, their use in characterizing in vivo cell behavior may help bring cellular therapy closer to clinical acceptance. Second, their use in lung imaging provides novel noninvasive interrogation of the ventilated airspaces without the need for complicated, hard-to-distribute hardware. This article reviews the current state of 19F-based cell tracking and lung imaging using magnetic resonance imaging and describes the link between the methods across these fields and how they may mutually benefit from solutions to mutual problems encountered when imaging 19F-containing compounds, as well as hardware and software advancements. PMID:27042089

Fluorspar

NASA Astrophysics Data System (ADS)

Pelham, L.

Fluorspar is the commercial name for the mineral fluorite, which commonly occurs as calcium fluoride (CaF2). Fluorspar is the most important commercial source of fluorine, which is a pale-yellow corrosive gas. Fluorspar is considered a strategic and critical commodity because U.S. import reliance is greater than 85% and fluorspar is necessary in most steel and aluminum production processes. Fluorine compounds are also used in the production of nuclear fuel. The chemical and ceramic industries are also significant users of fluorspar. There are many other diverse uses of fluorspar including water fluoridation. Strategic uses of fluorspar were reviewed and fluorspar-related technologies were assessed. Fluorspar reserves and supply-demand relationships were summarized. Economic factors and problems and the impact of environmental requirements on the fluorspar industry were overviewed.

Design, synthesis, and protein crystallography of biaryltriazoles as potent tautomerase inhibitors of macrophage migration inhibitory factor.

PubMed

Dziedzic, Pawel; Cisneros, José A; Robertson, Michael J; Hare, Alissa A; Danford, Nadia E; Baxter, Richard H G; Jorgensen, William L

2015-03-04

Optimization is reported for biaryltriazoles as inhibitors of the tautomerase activity of human macrophage migration inhibitory factor (MIF), a proinflammatory cytokine associated with numerous inflammatory diseases and cancer. A combined approach was taken featuring organic synthesis, enzymatic assaying, crystallography, and modeling including free-energy perturbation (FEP) calculations. X-ray crystal structures for 3a and 3b bound to MIF are reported and provided a basis for the modeling efforts. The accommodation of the inhibitors in the binding site is striking with multiple hydrogen bonds and aryl-aryl interactions. Additional modeling encouraged pursuit of 5-phenoxyquinolinyl analogues, which led to the very potent compound 3s. Activity was further enhanced by addition of a fluorine atom adjacent to the phenolic hydroxyl group as in 3w, 3z, 3aa, and 3bb to strengthen a key hydrogen bond. It is also shown that physical properties of the compounds can be modulated by variation of solvent-exposed substituents. Several of the compounds are likely the most potent known MIF tautomerase inhibitors; the most active ones are more than 1000-fold more active than the well-studied (R)-ISO-1 and more than 200-fold more active than the chromen-4-one Orita-13.

Design, Synthesis, and Protein Crystallography of Biaryltriazoles as Potent Tautomerase Inhibitors of Macrophage Migration Inhibitory Factor

DOE PAGES

Dziedzic, Pawel; Cisneros, José A.; Robertson, Michael J.; ...

2015-02-20

Optimization is reported for biaryltriazoles as inhibitors of the tautomerase activity of human macrophage migration inhibitory factor (MIF), a proinflammatory cytokine associated with numerous inflammatory diseases and cancer. A combined approach was taken featuring organic synthesis, enzymatic assaying, crystallography, and modeling including free-energy perturbation (FEP) calculations. X-ray crystal structures for 3a and 3b bound to MIF are reported and provided a basis for the modeling efforts. The accommodation of the inhibitors in the binding site is striking with multiple hydrogen bonds and aryl–aryl interactions. Additional modeling encouraged pursuit of 5-phenoxyquinolinyl analogues, which led to the very potent compound 3s. Activitymore » was further enhanced by addition of a fluorine atom adjacent to the phenolic hydroxyl group as in 3w, 3z, 3aa, and 3bb to strengthen a key hydrogen bond. We also show that physical properties of the compounds can be modulated by variation of solvent-exposed substituents. Several of the compounds are likely the most potent known MIF tautomerase inhibitors; the most active ones are more than 1000-fold more active than the well-studied (R)-ISO-1 and more than 200-fold more active than the chromen-4-one Orita-13.« less

Electrophilic trifluoromethylselenolation of terminal alkynes with Se-(trifluoromethyl) 4-methylbenzenesulfonoselenoate.

PubMed

Ghiazza, Clément; Tlili, Anis; Billard, Thierry

2017-01-01

Herein the nucleophilic addition of Se -(trifluoromethyl) 4-methylbenzenesulfonoselenoate, a stable and easy-to-handle reagent, to alkynes is described. This reaction provides trifluoromethylselenylated vinyl sulfones with good results and the method was extended also to higher fluorinated homologs. The obtained compounds are valuable building blocks for further syntheses of fluoroalkylselenolated molecules.

Interferometric studies of the refractive indices of some fluorine compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malik, Jim Gorden; Rogers, Max T.; Speirs, John L.

1954-08-01

It is the object of this investigation to construct an interferometer of the Rayleigh type and adapt it for two purposes; first, the measurement of the refractive indices of gases by an absolute method and, and second, the measurement of the refractive indices of very dilute solutions by the difference method.

NEW METABOLITES FROM THE MICROBIAL OXIDATION OF FLUORINATED AROMATIC COMPOUNDS. (R826113)

EPA Science Inventory

Abstract

m-Bromo-,,Photodegradation of Polyfluorinated Dibenzo-p-Dioxins in Organic Solvents: Experimental and Theoretical Studies.

PubMed

Zeng, Xiaolan; Qu, Ruijuan; Feng, Mingbao; Chen, Jing; Wang, Liansheng; Wang, Zunyao

2016-08-02

Eighteen polyfluorinated dibenzo-p-dioxins (PFDDs) were synthesized by pyrolysis of fluorophenols. Using a 500 W Xe lamp as the light source, the PFDDs photodegradation kinetics in n-hexane were investigated. The photolysis reactions obeyed the pseudo-first-order rate equation, and higher fluorinated PFDDs tended to photolyze more slowly. Theoretically calculated parameters reflecting the molecular structural properties were used to develop a new model of PFDDs photolysis rates. The results indicated that the substitution pattern for fluorine atoms and the C-O bond length were major factors in the photolysis of PFDDs. We selected octafluorinated dibenzo-p-dioxin (OFDD) as a representative PFDDs to explore the influence of solvent on the photolysis rate of PFDDs, and the results indicated that neither the polarity nor donor hydrogen of organic solvents are independent influencing factors. Mechanistic pathways for the photolysis of OFDD in n-hexane were first studied. The results indicated that photodegradation of OFDD produces octafluorinated dihydroxybiphenyls, octafluorinated phenoxyphenols, and fluorinated phenols. The major pathway for photodegradation of OFDD was C-O bond cleavage. Defluorination reactions did not occur during the photolysis process.

Efficient and Scalable Synthesis of 4-Carboxy-Pennsylvania Green Methyl Ester: A Hydrophobic Building Block for Fluorescent Molecular Probes.

PubMed

Woydziak, Zachary R; Fu, Liqiang; Peterson, Blake R

2014-01-01

Fluorinated fluorophores are valuable tools for studies of biological systems. However, amine-reactive single-isomer derivatives of these compounds are often very expensive. To provide an inexpensive alternative, we report a practical synthesis of 4-carboxy-Pennsylvania Green methyl ester. Derivatives of this hydrophobic fluorinated fluorophore, a hybrid of the dyes Oregon Green and Tokyo Green, are often cell permeable, enabling labeling of intracellular targets and components. Moreover, the low pKa of Pennsylvania Green (4.8) confers bright fluorescence in acidic cellular compartments such as endosomes, enhancing its utility for chemical biology investigations. To improve access to the key intermediate 2,7-difluoro-3,6-dihydroxyxanthen-9-one, we subjected bis-(2,4,5-trifluorophenyl)methanone to iterative nucleophilic aromatic substitution by hydroxide on scales of > 40 g. This intermediate was used to prepare over 15 grams of pure 4-carboxy-Pennsylvania Green methyl ester in 28% overall yield without requiring chromatography. This compound can be converted into the amine reactive N -hydroxysuccinimidyl ester in essentially quantitative yield for the synthesis of a wide variety of fluorescent molecular probes.

Single photon emission computed tomography/positron emission tomography imaging and targeted radionuclide therapy of melanoma: new multimodal fluorinated and iodinated radiotracers.

PubMed

Maisonial, Aurélie; Kuhnast, Bertrand; Papon, Janine; Boisgard, Raphaël; Bayle, Martine; Vidal, Aurélien; Auzeloux, Philippe; Rbah, Latifa; Bonnet-Duquennoy, Mathilde; Miot-Noirault, Elisabeth; Galmier, Marie-Josèphe; Borel, Michèle; Askienazy, Serge; Dollé, Frédéric; Tavitian, Bertrand; Madelmont, Jean-Claude; Moins, Nicole; Chezal, Jean-Michel

2011-04-28

This study reports a series of 14 new iodinated and fluorinated compounds offering both early imaging ((123)I, (124)I, (18)F) and systemic treatment ((131)I) of melanoma potentialities. The biodistribution of each (125)I-labeled tracer was evaluated in a model of melanoma B16F0-bearing mice, using in vivo serial γ scintigraphic imaging. Among this series, [(125)I]56 emerged as the most promising compound in terms of specific tumoral uptake and in vivo kinetic profile. To validate our multimodality concept, the radiosynthesis of [(18)F]56 was then optimized and this radiotracer has been successfully investigated for in vivo PET imaging of melanoma in B16F0- and B16F10-bearing mouse model. The therapeutic efficacy of [(131)I]56 was then evaluated in mice bearing subcutaneous B16F0 melanoma, and a significant slow down in tumoral growth was demonstrated. These data support further development of 56 for PET imaging ((18)F, (124)I) and targeted radionuclide therapy ((131)I) of melanoma using a single chemical structure.

2H{ 19F} REDOR for distance measurements in biological solids using a double resonance spectrometer

NASA Astrophysics Data System (ADS)

Grage, Stephan L.; Watts, Jude A.; Watts, Anthony

2004-01-01

A new approach for distance measurements in biological solids employing 2H{ 19F} rotational echo double resonance was developed and validated on 2H, 19F- D-alanine and an imidazopyridine based inhibitor of the gastric H +/K +-ATPase. The 2H- 19F double resonance experiments presented here were performed without 1H decoupling using a double resonance NMR spectrometer. In this way, it was possible to benefit from the relatively longer distance range of fluorine without the need of specialized fluorine equipment. A distance of 2.5 ± 0.3 Å was measured in the alanine derivative, indicating a gauche conformation of the two labels. In the case of the imidazopyridine compound a lower distance limit of 5.2 Å was determined and is in agreement with an extended conformation of the inhibitor. Several REDOR variants were compared, and their advantages and limitations discussed. Composite fluorine dephasing pulses were found to enhance the frequency bandwidth significantly, and to reduce the dependence of the performance of the experiment on the exact choice of the transmitter frequency.

Fluorination Effects on NOS Inhibitory Activity of Pyrazoles Related to Curcumin.

PubMed

Nieto, Carla I; Cabildo, María Pilar; Cornago, María Pilar; Sanz, Dionisia; Claramunt, Rosa M; Torralba, María Carmen; Torres, María Rosario; Elguero, José; García, José A; López, Ana; Acuña-Castroviejo, Darío

2015-08-28

A series of new (E)-3(5)-[β-(aryl)-ethenyl]-5(3)-phenyl-1H-pyrazoles bearing fluorine atoms at different positions of the aryl group have been synthesized starting from the corresponding β-diketones. All compounds have been characterized by elemental analysis, DSC as well as NMR (¹H, (13)C, (19)F and (15)N) spectroscopy in solution and in solid state. Three structures have been solved by X-ray diffraction analysis, confirming the tautomeric forms detected by solid state NMR. The in vitro study of their inhibitory potency and selectivity on the activity of nNOS and eNOS (calcium-calmodulin dependent) as well as iNOS (calcium-calmodulin independent) isoenzymes is presented. A qualitative structure-activity analysis allowed the establishment of a correlation between the presence/ absence of different substituents with the inhibition data proving that fluorine groups enhance the biological activity. (E)-3(5)-[β-(3-Fluoro-4-hydroxyphenyl)-ethenyl]-5(3)-phenyl-1H-pyrazole (13), is the best inhibitor of iNOS, being also more selective towards the other two isoforms.

Carbocations from Oxidized Metabolites of Benzo[a]anthracene. A Computational Study of Their Methylated and Fluorinated Derivatives and Guanine Adducts

PubMed Central

Borosky, Gabriela L.; Laali, Kenneth K.

2008-01-01

Structure-reactivity relationships and substituent effects on carbocation stability in benzo[a] anthracene (BA) derivatives have been studied computationally at the B3LYP/6-31G* and MP2/6-31G** levels. Bay-region carbocations are formed by O-protonation of the 1,2-epoxides in barrierless processes. This process is energetically more favored as compared to carbocation generation via zwitterion formation/O-protonation, via single electron oxidation to generate a radical cation, or via benzylic hydroxylation. Relative carbocation stabilities were determined in the gas phase and in water as solvent (PCM method). Charge delocalization mode in the BA carbocation framework was deduced from NPA-derived changes in charges, and substitution by methyl or fluorine was studied at different positions selected on basis of the carbocation charge density. A bay-region methyl group produces structural distortion with consequent deviation from planarity of the aromatic system, which destabilizes the epoxide, favoring ring opening. Whereas fluorine substitution at sites bearing significant positive charge leads to carbocation stabilization by fluorine p-π back-bonding, a fluorine atom at a ring position which presented negative charge density leads to inductive destabilization. Methylated derivatives are less sensitive to substituent effects as compared to the fluorinated analogues. Although the solvent decreases the exothermicity of the epoxide ring opening reactions due to greater stabilization of the reactants, it provokes no changes in relative reactivities. Relative energies in the resulting bay-region carbocations are examined taking into account the available biological activity data on these compounds. In selected cases, quenching of bay-region carbocations was investigated by analyzing relative energies (in the gas phase and in water) and geometries of their guanine adducts formed via covalent bond formation with the exocyclic amino group and with the N-7. PMID:16841957

Electrophilic fluorinating reagent mediated synthesis of fluorinated alpha-keto Ethers, benzil, and 6,6'-dialkoxy-2,2'-bipyridines.

PubMed

Manandhar, Sudha; Singh, Rajendra P; Eggers, Gary V; Shreeve, Jean'ne M

2002-09-06

Interactions of various fluorinated and nonfluorinated alcohols with trans-stilbene in the presence of electrophilic reagents were studied. Under neat conditions, reactions of trans-stilbene (1) with fluorinated alcohols, R(f)OH (R(f) = CF3CH2-, CFH2CH2-, CF3CF2CH2-, CF2H(CF2)3CH2-, (CF3)2CH-, (CF3)3C- (2a-f) in the presence of an electrophilic reagent, 1-(chloromethyl)-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (Selectfluor) or N,N-difluoro-2,2'-bipyridinium bis(tetrafluoroborate) (MEC-31), gave alpha-keto ethers (3a-f) and benzil (4) in good to moderate yields. alpha-Keto ether and benzil formation was very much dependent on the reaction time, the degree of fluorination of the alcohols, and whether a solvent such as CH3CN, DMF or DMA was utilized. In solution, alpha-keto ethers and benzil did not form. Interestingly, under neat conditions, nonfluorinated alcohols, ROH (R = CH3-, CH3CH2-, CH3CH2CH2-, CH3CH2CH2CH2-, CH3CH2CH2CH2CH2CH2-) (5g-k) did not react with trans-stilbene in the presence of MEC-31 but gave 6,6'-dialkoxy-2,2'-bipyridines (6g-k), regioselectively, in excellent isolated yields. On the other hand, fluorinated alcohols did not react with MEC-31. Reaction of MEC-31 with an excess of diethylene glycol (7) gave the bipyridine derivative (8) in 88% isolated yield. Reaction of 8 either with diethylaminosulfur trifluoride (DAST) or bis(2-methoxyethyl)aminosulfur trifluoride (Deoxofluor) readily produced the corresponding difluoro derivative (9) in 85% isolated yield. All new compounds have been characterized by spectroscopic and elemental analysis.

Conformational dynamics in fluorophenylcarbamoyl-alpha-chymotrypsins.

PubMed

Kairi, M; Gerig, J T

1990-06-19

A series of fluorine-substituted diphenylcarbamoyl chlorides have been synthesized and used to prepare corresponding diphenylcarbamoylated derivatives of alpha-chymotrypsin. The enzyme is rapidly inactivated by these compounds, as has been previously observed for the unsubstituted chloride, and the derivatives are stable enough to permit extensive studies by fluorine NMR spectroscopy. In combination with previously reported results, these NMR experiments suggest that the aromatic rings of a diphenylcarbamoyl group attached to chymotrypsin may be found in two magnetically and dynamically distinguishable sites, with exchange between these sites taking place by a process that involves rotation about the carbamoyl N-CO bond and localized unfolding of the enzyme. The extent to which a given fluoroaromatic ring is found in one of these sites is dependent on the position of the fluorine substituent and the nature of the partner aromatic ring. It is found that a 2-fluorophenyl ring, when present, dominantly determines site occupation, while a 3-fluorophenyl ring has no effects that are detectably different from those of an unsubstituted phenyl ring. There is evidence for slow aromatic ring rotation within at least one of the phenyl ring interaction sites. Saturation transfer and lineshape methods provide information about the rates of interconversion of the N-phenyl groups between these sites. Line-width, spin-lattice relaxation times and fluorine-proton nuclear Overhauser effects determined at 282 and 470 MHz are reported for each system examined.

1,2-Fluorine Radical Rearrangements: Isomerization Events in Perfluorinated Radicals.

PubMed

Van Hoomissen, Daniel J; Vyas, Shubham

2017-11-16

Devising effective degradation technologies for perfluoroalkyl substances (PFASs) is an active area of research, where the molecular mechanisms involving both oxidative and reductive pathways are still elusive. One commonly neglected pathway in PFAS degradation is fluorine atom migration in perfluoroalkyl radicals, which was largely assumed to be implausible because of the high C-F bond strength. Using density functional theory calculations, it was demonstrated that 1,2-F atom migrations are thermodynamically favored when the fluorine atom migrated from a less branched carbon center to a more branched carbon center. Activation barriers for these rearrangements were within 19-29 kcal/mol, which are possible to easily overcome at elevated temperatures or in photochemically activated species in the gas or aqueous phase. It was also found that the activation barriers for the 1,2-F atom migration are lowered as much as by 10 kcal/mol when common oxidative degradation products such as HF assisted the rearrangements or if the resulting radical center was stabilized by vicinal π-bonds. Natural bond orbital analyses showed that fluorine moves as a radical in a noncharge-separated state. These findings add an important reaction to the existing knowledge of mechanisms for PFAS degradation and highlights the fact that 1,2-F atom shifts may be a small channel for isomerization of these compounds, but upon availability of mineralization products, this isomerization process could become more prominent.

Synthesis and Preclinical Evaluation of Three Novel Fluorine-18 Labeled Radiopharmaceuticals for P-Glycoprotein PET Imaging at the Blood-Brain Barrier.

PubMed

Savolainen, Heli; Cantore, Mariangela; Colabufo, Nicola A; Elsinga, Philip H; Windhorst, Albert D; Luurtsema, Gert

2015-07-06

P-Glycoprotein (P-gp), along with other transporter proteins at the blood-brain barrier (BBB), limits the entry of many pharmaceuticals into the brain. Altered P-gp function has been found in several neurological diseases. To study the P-gp function, many positron emission tomography (PET) radiopharmaceuticals have been developed. Most P-gp radiopharmaceuticals are labeled with carbon-11, while labeling with fluorine-18 would increase their applicability due to longer half-life. Here we present the synthesis and in vivo evaluation of three novel fluorine-18 labeled radiopharmaceuticals: 4-((6,7-dimethoxy-3,4-dihydroisoquinolin-2(1H)-yl)methyl)-2-(4-fluorophenyl)oxazole (1a), 2-biphenyl-4-yl-2-fluoroethoxy-6,7-dimethoxy-1,2,3,4-tetrahydro-isoquinoline (2), and 5-(1-(2-fluoroethoxy))-[3-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-propyl]-5,6,7,8-tetrahydronaphthalen (3). Compounds were characterized as P-gp substrates in vitro, and Mdr1a/b((-/-))Bcrp1((-/-)) and wild-type mice were used to assess the substrate potential in vivo. Comparison was made to (R)-[(11)C]verapamil, which is currently the most frequently used P-gp substrate. Compound [(18)F]3 was performing the best out of the new radiopharmaceuticals; it had 2-fold higher brain uptake in the Mdr1a/b((-/-))Bcrp1((-/-)) mice compared to wild-type and was metabolically quite stable. In the plasma, 69% of the parent compound was intact after 45 min and 96% in the brain. Selectivity of [(18)F]3 to P-gp was tested by comparing the uptake in Mdr1a/b((-/-)) mice to uptake in Mdr1a/b((-/-))Bcrp1((-/-)) mice, which was statistically not significantly different. Hence, [(18)F]3 was found to be selective for P-gp and is a promising new radiopharmaceutical for P-gp PET imaging at the BBB.

New fluorinated rhodamines for optical microscopy and nanoscopy.

PubMed

Mitronova, Gyuzel Yu; Belov, Vladimir N; Bossi, Mariano L; Wurm, Christian A; Meyer, Lars; Medda, Rebecca; Moneron, Gael; Bretschneider, Stefan; Eggeling, Christian; Jakobs, Stefan; Hell, Stefan W

2010-04-19

New photostable rhodamine dyes represented by the compounds 1 a-r and 3-5 are proposed as efficient fluorescent markers with unique combination of structural features. Unlike rhodamines with monoalkylated nitrogen atoms, N',N-bis(2,2,2-trifluoroethyl) derivatives 1 e, 1 i, 1 j, 3-H and 5 were found to undergo sulfonation of the xanthene fragment at the positions 4' and 5'. Two fluorine atoms were introduced into the positions 2' and 7' of the 3',6'-diaminoxanthene fragment in compounds 1 a-d, 1 i-l and 1 m-r. The new rhodamine dyes may be excited with λ=488 or 514 nm light; most of them emit light at λ=512-554 nm (compounds 1 q and 1r at λ=576 and 589 nm in methanol, respectively) and have high fluorescence quantum yields in solution (up to 98 %), relatively long excited-state lifetimes (>3 ns) and are resistant against photobleaching, especially at high laser intensities, as is usually applied in confocal microscopy. Sulfonation of the xanthene fragment with 30 % SO3 in H2SO4 is compatible with the secondary amide bond (rhodamine-CON(Me)CH2CH2COOH) formed with MeNHCH2CH2COOCH3 to providing the sterically unhindered carboxylic group required for further (bio)conjugation reactions. After creating the amino reactive sites, the modified derivatives may be used as fluorescent markers and labels for (bio)molecules in optical microscopy and nanoscopy with very-high light intensities. Further, the new rhodamine dyes are able to pass the plasma membrane of living cells, introducing them as potential labels for recent live-cell-tag approaches. We exemplify the excellent performance of the fluorinated rhodamines in optical microscopy by fluorescence correlation spectroscopy (FCS) and stimulated emission depletion (STED) nanoscopy experiments. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Global and local approaches to population analysis: Bonding patterns in superheavy element compounds

NASA Astrophysics Data System (ADS)

Oleynichenko, Alexander; Zaitsevskii, Andréi; Romanov, Stepan; Skripnikov, Leonid V.; Titov, Anatoly V.

2018-03-01

Relativistic effective atomic configurations of superheavy elements Cn, Nh and Fl and their lighter homologues (Hg, Tl and Pb) in their simple compounds with fluorine and oxygen are determined using the analysis of local properties of molecular Kohn-Sham density matrices in the vicinity of heavy nuclei. The difference in populations of atomic spinors with the same orbital angular momentum and different total angular momenta is demonstrated to be essential for understanding the peculiarities of chemical bonding in superheavy element compounds. The results are fully compatible with those obtained by the relativistic iterative version of conventional projection analysis of global density matrices.

Evaluation of sample recovery of malodorous livestock gases from air sampling bags, solid-phase microextraction fibers, Tenax TA sorbent tubes, and sampling canisters.

PubMed

Koziel, Jacek A; Spinhirne, Jarett P; Lloyd, Jenny D; Parker, David B; Wright, Donald W; Kuhrt, Fred W

2005-08-01

Odorous gases associated with livestock operations are complex mixtures of hundreds if not thousands of compounds. Research is needed to know how best to sample and analyze these compounds. The main objective of this research was to compare recoveries of a standard gas mixture of 11 odorous compounds from the Carboxen/PDMS 75-microm solid-phase microextraction fibers, polyvinyl fluoride (PVF; Tedlar), fluorinated ethylene propylene copolymer (FEP; Teflon), foil, and polyethylene terephthalate (PET; Melinex) air sampling bags, sorbent 2,b-diphenylene-oxide polymer resin (Tenax TA) tubes, and standard 6-L Stabilizer sampling canisters after sample storage for 0.5, 24, and 120 (for sorbent tubes only) hrs at room temperature. The standard gas mixture consisted of 7 volatile fatty acids (VFAs) from acetic to hexanoic, and 4 semivolatile organic compounds including p-cresol, indole, 4-ethylphenol, and 2'-aminoacetophenone with concentrations ranging from 5.1 ppb for indole to 1270 ppb for acetic acid. On average, SPME had the highest mean recovery for all 11 gases of 106.2%, and 98.3% for 0.5- and 24-hr sample storage time, respectively. This was followed by the Tenax TA sorbent tubes (94.8% and 88.3%) for 24 and 120 hr, respectively; PET bags (71.7% and 47.2%), FEP bags (75.4% and 39.4%), commercial Tedlar bags (67.6% and 22.7%), in-house-made Tedlar bags (47.3% and 37.4%), foil bags (16.4% and 4.3%), and canisters (4.2% and 0.5%), for 0.5 and 24 hr, respectively. VFAs had higher recoveries than semivolatile organic compounds for all of the bags and canisters. New FEP bags and new foil bags had the lowest and the highest amounts of chemical impurities, respectively. New commercial Tedlar bags had measurable concentrations of N,N-dimethyl acetamide and phenol. Foil bags had measurable concentrations of acetic, propionic, butyric, valeric, and hexanoic acids.

NbF5 and TaF5: Assignment of 19F NMR resonances and chemical bond analysis from GIPAW calculations

NASA Astrophysics Data System (ADS)

Biswal, Mamata; Body, Monique; Legein, Christophe; Sadoc, Aymeric; Boucher, Florent

2013-11-01

The 19F isotropic chemical shifts (δiso) of two isomorphic compounds, NbF5 and TaF5, which involve six nonequivalent fluorine sites, have been experimentally determined from the reconstruction of 1D 19F MAS NMR spectra. In parallel, the corresponding 19F chemical shielding tensors have been calculated using the GIPAW method for both experimental and DFT-optimized structures. Furthermore, the [M4F20] units of NbF5 and TaF5 being held together by van der Waals interactions, the relevance of Grimme corrections to the DFT optimization processes has been evaluated. However, the semi-empirical dispersion correction term introduced by such a method does not show any significant improvement. Nonetheless, a complete and convincing assignment of the 19F NMR lines of NbF5 and TaF5 is obtained, ensured by the linearity between experimental 19F δiso values and calculated 19F isotropic chemical shielding σiso values. The effects of the geometry optimizations have been carefully analyzed, confirming among other matters, the inaccuracy of the experimental structure of NbF5. The relationships between the fluorine chemical shifts, the nature of the fluorine atoms (bridging or terminal), the position of the terminal ones (opposite or perpendicular to the bridging ones), the fluorine charges, the ionicity and the length of the M-F bonds have been established. Additionally, for three of the 19F NMR lines of NbF5, distorted multiplets, arising from 1J-coupling and residual dipolar coupling between the 19F and 93Nb nuclei, were simulated yielding to values of 93Nb-19F 1J-coupling for the corresponding fluorine sites.

Alkoxide-based magnesium electrolyte compositions for magnesium batteries

DOEpatents

Dai, Sheng; Sun, Xiao-Guang; Liao, Chen; Guo, Bingkun

2018-01-30

Alkoxide magnesium halide compounds having the formula: RO--Mg--X (1) wherein R is a saturated or unsaturated hydrocarbon group that is unsubstituted, or alternatively, substituted with one or more heteroatom linkers and/or one or more heteroatom-containing groups comprising at least one heteroatom selected from fluorine, nitrogen, oxygen, sulfur, and silicon; and X is a halide atom. Also described are electrolyte compositions containing a compound of Formula (1) in a suitable polar aprotic or ionic solvent, as well as magnesium batteries in which such electrolytes are incorporated.

Structure-activity relationships of tetramethylpiperidine-substituted phenazines against Mycobacterium leprae in vitro.

PubMed Central

Franzblau, S G; White, K E; O'Sullivan, J F

1989-01-01

In a previous study of structure-activity relationships of selected phenazines against Mycobacterium leprae in vitro, compounds containing a 2,2,6,6-tetramethylpiperidine substitution at the imino nitrogen were most active. Therefore, the effect of substitution at the para positions of the phenyl and anilino groups in tetramethylpiperidine-substituted phenazines was assessed. As determined by radiorespirometry, activity in ascending order was observed in compounds substituted with hydrogens or fluorines, ethoxy groups, methyl groups, chlorines, and bromines and correlated with partition coefficients in octanol-water. PMID:2692516

Difluoromethyl 2-pyridyl sulfone: a new gem-difluoroolefination reagent for aldehydes and ketones.

PubMed

Zhao, Yanchuan; Huang, Weizhou; Zhu, Lingui; Hu, Jinbo

2010-04-02

Difluoromethyl 2-pyridyl sulfone, a previously unknown compound, was found to act as a novel and efficient gem-difluoroolefination reagent for both aldehydes and ketones. It was found that the fluorinated sulfinate intermediate in the reaction is relatively stable, which can be observed by (19)F NMR and trapped with CH(3)I.

Surface modification of amorphous substrates by disulfide derivatives: A photo-assisted route to direct functionalization of chalcogenide glasses

NASA Astrophysics Data System (ADS)

Amalric, Julien; Marchand-Brynaert, Jacqueline

2011-12-01

A novel route for chalcogenide glass surface modification is disclosed. The formation of an organic monolayer from disulfide derivatives is studied on two different glasses of formula GexAsySez by water contact angle measurement, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR). The potential anchoring group is the disulfide functionality. Since thioctic acid derivatives absorb around 335 nm, an irradiation step is included, in order to favor S-S disruption. Three types of disulfide compounds are grafted onto small glass breaks for contact angle and XPS analyses. The results show effective changes of surface state. According to contact angle measurement, the deposited organic layer functionalized by a small polyethylene glycol chain leads to a more hydrophilic surface, long alkyl chain or a perfluorinated carbon chain leads to a more hydrophobic surface. XPS shows the presence at the surface of an organic layer with sulfur and ethylene oxide chains, or augmentation of organic carbons or fluorine and Csbnd F bonds. The photo-assisted grafting of the disulfides onto an ATR prism made of chalcogenide glass shows that this surface modification process does not affect infrared transparency, despite UV treatment, and accurate structural analysis can be performed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buragohain, Amlan; Couck, Sarah; Van Der Voort, Pascal

Four existing and three new functionalized chromium terephthalates having MIL-101 topology and denoted as Cr-MIL-101-X (existing ones with X=–F, 1-F; –Cl, 2-Cl; –Br, 3-Br; –CH{sub 3}, 4-CH{sub 3}; new ones with X=–C{sub 6}H{sub 4}, 5-C{sub 6}H{sub 4}; –F{sub 2}, 6-F{sub 2}, –(CH{sub 3}){sub 2}, 7-(CH{sub 3}){sub 2}) were synthesized under hydrothermal conditions. All the materials except 5-C{sub 6}H{sub 4} could be prepared by a general synthetic route, in which the mixtures of CrO{sub 3}, H{sub 2}BDC-X (BDC=1,4-benzenedicarboxylate) linkers, conc. HCl and water with a molar ratio of 1:1:3.9:222.2 were reacted at 180 °C for 144 h. Compared to the 144more » h of synthesis time, three of the compounds, namely 1-Cl, 2-Br and 5-C{sub 6}H{sub 4}, could be prepared in much shorter reaction times (12–18 h at 180–210 °C). The materials possess high thermal stability up to 270–300 °C in an air atmosphere. The activated compounds exhibit significant porosity (S{sub BET} range: 1273–2135 m{sup 2} g{sup −1}). At 0 °C and 1 bar, the CO{sub 2} adsorption capacities of the compounds fall in the 1.7–2.9 mmol g{sup −1} range. Compounds 1-F and 6-F{sub 2} showed enhanced CO{sub 2} uptake values compared to parent Cr-MIL-101. The benzene adsorption capacities of the compounds lie in the range of 66.2–139.5 molecules per unit cell at 50 °C and p/p{sub 0}=0.35. The increased benzene uptake value of 1-F compared to un-functionalized Cr-MIL-101 and 4-CH{sub 3} suggests that the fluorination has induced more hydrophobicity in Cr-MIL-101 as compared to the methylation. - Graphical abstract: Benzene adsorption by seven functionalized Cr-MIL-101-X metal-organic framework (MOF) materials Display Omitted - Highlights: • Seven functionalized Cr-MIL-101-X materials were synthesized solvothermally. • All Cr-MIL-101-X materials exhibited high thermal stability up to 270–300 °C in air. • All Cr-MIL-101-X compounds displayed considerable porosity towards N{sub 2}, CO{sub 2} and benzene. • Mono- and di-fluorinated Cr-MIL-101 materials showed enhanced CO{sub 2} adsorption capacities. • Cr-MIL-101-F adsorbed more benzene than non- and methyl-functionalized Cr-MIL-101.« less

Rapid dehalogenation of pesticides and organics at the interface of reduced graphene oxide-silver nanocomposite.

PubMed

Koushik, Dibyashree; Sen Gupta, Soujit; Maliyekkal, Shihabudheen M; Pradeep, T

2016-05-05

This paper reports dehalogenation of various organohalides, especially aliphatic halocarbons and pesticides at reduced graphene oxide-silver nanocomposite (RGO@Ag). Several pesticides as well as chlorinated and fluorinated alkyl halides were chosen for this purpose. The composite and the products of degradation were characterized thoroughly by means of various microscopic and spectroscopic techniques. A sequential two-step mechanism involving dehalogenation of the target pollutants by silver nanoparticles followed by adsorption of the degraded compounds onto RGO was revealed. The composite showed unusual adsorption capacity, as high as 1534 mg/g, which facilitated the complete removal of the pollutants. Irrespective of the pollutants tested, a pseudo-second-order rate equation best described the adsorption kinetics. The affinity of the composite manifested chemical differences. The high adsorption capacity and re-usability makes the composite an excellent substrate for purification of water. Copyright © 2016 Elsevier B.V. All rights reserved.

Fluorinated Dodecaphenylporphyrins: Synthetic and Electrochemical Studies Including the First Evidence of Intramolecular Electron Transfer Between an Fe(II) Porphyrin -Anion Radical and an Fe(I) Porphyrin

DOE Office of Scientific and Technical Information (OSTI.GOV)

D'Souza, F.; Forsyth, T.P.; Fukuzumi, S.

1998-10-19

Dodecaphenylporphyrins with varying degrees of fluorination of the peripheral phenyl rings (FXDPPS) were synthesized as model compounds for studying electronic effects in nonplan~ porphyrins, and detailed electrochemical studies of the chloroiron(HI) complexes of these compounds were undertaken. The series of porphyrins, represented as FeDPPCl and as FeFXDPPCl where x = 4, 8 (two isomers), 12, 20,28 or 36, could be reversibly oxidized by two electrons in dichloromethane to give n-cation radicals and n-dications. All of the compounds investigated could also be reduced by three electrons in benzonitrile or pyridine. In benzonitrile, three reversible reductions were observed for the unfluorinated compoundmore » FeDPPC1, whereas the FeFXDPPCl complexes generally exhibited irreversible first and second reductions which were coupled to chemical reactions. The chemical reaction associated with the first reduction involved a loss of the chloride ion after generation of Fe FXDPPC1. The second chemical reaction involved a novel intramolecular electron transfer between the initially generated Fe(H) porphyrin n-anion radical and the final Fe(I) porphyrin reduction product. In pyridine, three reversible one electron reductions were observed with the second reduction affording stable Fe(II) porphyrin o - anion radicals for ail of the complexes investigated.« less

Intrinsic Thermodynamics and Structures of 2,4- and 3,4-Substituted Fluorinated Benzenesulfonamides Binding to Carbonic Anhydrases.

PubMed

Zubrienė, Asta; Smirnov, Alexey; Dudutienė, Virginija; Timm, David D; Matulienė, Jurgita; Michailovienė, Vilma; Zakšauskas, Audrius; Manakova, Elena; Gražulis, Saulius; Matulis, Daumantas

2017-01-20

The goal of rational drug design is to understand structure-thermodynamics correlations in order to predict the chemical structure of a drug that would exhibit excellent affinity and selectivity for a target protein. In this study we explored the contribution of added functionalities of benzenesulfonamide inhibitors to the intrinsic binding affinity, enthalpy, and entropy for recombinant human carbonic anhydrases (CA) CA I, CA II, CA VII, CA IX, CA XII, and CA XIII. The binding enthalpies of compounds possessing similar chemical structures and affinities were found to be very different, spanning a range from -90 to +10 kJ mol -1 , and are compensated by a similar opposing entropy contribution. The intrinsic parameters of binding were determined by subtracting the linked protonation reactions. The sulfonamide group pK a values of the compounds were measured spectrophotometrically, and the protonation enthalpies were measured by isothermal titration calorimetry (ITC). Herein we describe the development of meta- or ortho-substituted fluorinated benzenesulfonamides toward the highly potent compound 10 h, which exhibits an observed dissociation constant value of 43 pm and an intrinsic dissociation constant value of 1.1 pm toward CA IX, an anticancer target that is highly overexpressed in various tumors. Fluorescence thermal shift assays, ITC, and X-ray crystallography were all applied in this work. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recent developments in polyfluoroalkyl compounds research: a focus on human/environmental health impact, suggested substitutes and removal strategies.

PubMed

Mudumbi, John Baptist Nzukizi; Ntwampe, Seteno Karabo Obed; Matsha, Tandi; Mekuto, Lukhanyo; Itoba-Tombo, Elie Fereche

2017-08-01

Between the late 1940s and early 1950s, humans manufactured polyfluoroalkyl compounds (PFCs) using electrochemical fluorination and telomerisation technologies, whereby hydrogen atoms are substituted by fluorine atoms, thus conferring unnatural and unique physicochemical properties to these compounds. Presently, there are wide ranges of PFCs, and owing to their bioaccumulative properties, they have been detected in various environmental matrices and in human sera. It has thus been suggested that they are hazardous. Hence, this review aims at highlighting the recent development in PFC research, with a particular focus on perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS), the most studied and predominantly found PFCs in various environmental matrices, although recent reports have included perfluorobutane sulfonate (PFBS), which was previously regarded as innocuously harmless, when compared to its counterparts, PFOA and PFOS. As such, proper investigations are thus required for a better understanding of short-chain PFC substitutes, which have been suggested as suitable replacements to long-chained PFCs, although these substitutes have also been suggested to pose various health risks comparable to those associated with long-chain PFCs. Similarly, several novel technologies, such as PFC reduction using zero-valent iron, including removal at point of use, adsorption and coagulation, have been proposed. However, regardless of how efficient removers some of these techniques have proven to be, short-chain PFCs remain a challenge to overcome for scientists, in this regard.

Emerging poly- and perfluoroalkyl substances in the aquatic environment: A review of current literature.

PubMed

Xiao, Feng

2017-11-01

Poly- and perfluoroalkyl substances (PFASs) comprise a group of synthetic organic surfactants with a wide range of industrial and commercial applications. A few PFASs such as perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are now known to be ubiquitously present in the aquatic environment. They have become a global concern because of the toxicity and bioaccumulative properties. With the increasing availability of high-resolution mass spectrometers, many novel PFASs have been identified. Studies published between 2009 and 2017 have discovered 455 new PFASs (including nine fully and 446 partially fluorinated compounds), 45%, 29%, 17%, and 8% of which are anions, zwitterions, cations, and neutrals, respectively. They have been identified in natural waters, fish, sediments, wastewater, activated sludge, soils, aqueous film-forming foams, and commercial fluoropolymer surfactants. This article integrates and critically evaluates what is known about these newly identified PFASs. It discusses the different aspects of detection methodologies. It also surveys the removal of these compounds during conventional and advanced drinking-water and wastewater treatment, predicts the relevant physicochemical properties by means of four software programs, and identifies major knowledge gaps. Notably, a number of these newly identified PFASs are potential precursor compounds of PFOS and PFOA. Studies are critically needed to understand the removal and transformation of these compounds in natural and engineered environmental systems and their contribution, if any, to the secondary formation of PFOS and PFOA in these systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Rearrangement of 3-Membered 1,1,2-Trifluorobromonium and Iodonium Ions and Comparison of Trifluorochloronium to Fluorocarbeniuim Ions (Postprint)

DTIC Science & Technology

2008-01-01

The steric effect and repulsive forces from the lone-pair electrons on the fluorine atoms of 5 shield the carbon nucleus, rendering it resistant to... Electrophilic addition of Cl2 to alkene 2 gives 2% of rearranged product (Table 3, run 5). Intermediate 5 (Scheme 1, X ) Y ) Cl; Z ) Br) is 22.1 kcal...71 and 190. Chambers, R. D. Fluorine in Organic Chemistry; Wiley: New York, 1973; p 98. (4) (a) Heine, H. W.; Siegfried, W. J. Am. Chem. Soc. 1954

Fabrication of large-scale ripples on fluorine-doped tin oxide films by femtosecond laser irradiation

NASA Astrophysics Data System (ADS)

Han, Yan-Hua; Li, Yan; Zhao, Xiu-Li; Qu, Shi-Liang

2014-09-01

The large-scale uniform self-organized ripples are fabricated on fluorine-doped tin oxide (FTO) coated glass by femtosecond laser. They can be smoothly linked in a horizontal line with the moving of XYZ stage by setting its velocity and the repetition rate of the laser. The ripple-to-ripple linking can also be realized through line-by-line scanning on a vertical level. The mechanism analysis shows that the seeding effect plays a key role in the linking of ripples.

Biocompatible Nanocoatings of Fluorinated Polyphosphazenes through Aqueous Assembly

DOE PAGES

Selin, Victor; Albright, Victoria; Ankner, John Francis; ...

2018-02-23

Nonionic fluorinated polyphosphazenes, such as poly[bis(trifluoroethoxy)phosphazene] (PTFEP), display superb biocompatibility, yet their deposition to surfaces has been limited to solution casting from organic solvents or thermal molding. Here in this paper, hydrophobic coatings of fluorinated polyphosphazenes are demonstrated through controlled deposition of ionic fluorinated polyphosphazenes (iFPs) from aqueous solutions using the layer-by-layer (LbL) technique. Specifically, the assemblies included poly[(carboxylatophenoxy)(trifluoroethoxy)phosphazenes] with varied content of fluorine atoms as iFPs (or poly[bis(carboxyphenoxy)phosphazene] (PCPP) as a control nonfluorinated polyphosphazene) and a variety of polycations. Hydrophobic interactions largely contributed to the formation of LbL films of iFPs with polycations, leading to linear growth and extremelymore » low water uptake. Hydrophobicity-enhanced ionic pairing within iFP/BPEI assemblies gave rise to large-amplitude oscillations in surface wettability as a function of capping layer, which were the largest for the most fluorinated iFP, while control PCPP/polycation systems remained hydrophilic regardless of the film top layer. Neutron reflectometry (NR) studies indicated superior layering and persistence of such layering in salt solution for iFP/BPEI films as compared to control PCPP/polycation systems. Hydrophobicity of iFP-capped LbL coatings could be further enhanced by using a highly porous polyester surgical felt rather than planar substrates for film deposition. Importantly, iFP/polycation coatings displayed biocompatibility which was similar to or superior to that of solution-cast coatings of a clinically validated material (PTFEP), as demonstrated by the hemolysis of the whole blood and protein adsorption studies.« less

Biocompatible Nanocoatings of Fluorinated Polyphosphazenes through Aqueous Assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Selin, Victor; Albright, Victoria; Ankner, John Francis

Nonionic fluorinated polyphosphazenes, such as poly[bis(trifluoroethoxy)phosphazene] (PTFEP), display superb biocompatibility, yet their deposition to surfaces has been limited to solution casting from organic solvents or thermal molding. Here in this paper, hydrophobic coatings of fluorinated polyphosphazenes are demonstrated through controlled deposition of ionic fluorinated polyphosphazenes (iFPs) from aqueous solutions using the layer-by-layer (LbL) technique. Specifically, the assemblies included poly[(carboxylatophenoxy)(trifluoroethoxy)phosphazenes] with varied content of fluorine atoms as iFPs (or poly[bis(carboxyphenoxy)phosphazene] (PCPP) as a control nonfluorinated polyphosphazene) and a variety of polycations. Hydrophobic interactions largely contributed to the formation of LbL films of iFPs with polycations, leading to linear growth and extremelymore » low water uptake. Hydrophobicity-enhanced ionic pairing within iFP/BPEI assemblies gave rise to large-amplitude oscillations in surface wettability as a function of capping layer, which were the largest for the most fluorinated iFP, while control PCPP/polycation systems remained hydrophilic regardless of the film top layer. Neutron reflectometry (NR) studies indicated superior layering and persistence of such layering in salt solution for iFP/BPEI films as compared to control PCPP/polycation systems. Hydrophobicity of iFP-capped LbL coatings could be further enhanced by using a highly porous polyester surgical felt rather than planar substrates for film deposition. Importantly, iFP/polycation coatings displayed biocompatibility which was similar to or superior to that of solution-cast coatings of a clinically validated material (PTFEP), as demonstrated by the hemolysis of the whole blood and protein adsorption studies.« less

Neurotoxicity of Legacy and Emerging Persistent Organic Chemicals: A Proteomic Approach to Understand Adverse Outcome Pathways

EPA Science Inventory

During the past century, a vast number of persistent organic chemicals (POCs) have been manufactured and used in industrial, agricultural, public health, consumer products and other applications. Widespread use of legacy POCs, including chlorinated, brominated and fluorinated com...

Tribology and stability of organic monolayers on CrN: a comparison among silane, phosphonate, alkene, and alkyne chemistries.

PubMed

Pujari, Sidharam P; Li, Yan; Regeling, Remco; Zuilhof, Han

2013-08-20

The fabrication of chemically and mechanically stable monolayers on the surfaces of various inorganic hard materials is crucial to the development of biomedical/electronic devices. In this Article, monolayers based on the reactivity of silane, phosphonate, 1-alkene, and 1-alkyne moieties were obtained on the hydroxyl-terminated chromium nitride surface. Their chemical stability and tribology were systematically investigated. The chemical stability of the modified CrN surfaces was tested in aqueous media at 60 °C at pH 3, 7, and 11 and monitored by static water contact angle measurements, X-ray photoelectron spectroscopy (XPS), ellipsometry, and Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS). The tribological properties of the resulting organic monolayers with different end groups (fluorinated or nonfluorinated) were studied using atomic force microscopy (AFM). It was found that the fluorinated monolayers exhibit a dramatic reduction of adhesion and friction force as well as excellent wear resistance compared to those of nonfluorinated coatings and bare CrN substrates. The combination of remarkable chemical stability and superior tribological properties makes these fluorinated monolayers promising candidates for the development of robust high-performance devices.

[Effect of inorganic fluorine on living organisms of different phylogenetic level].

PubMed

Agalakova, N I; Gusev, G P

2011-01-01

The presented review summarizes literature data on pathways of the inorganic fluoride intake into the plant, animal, and human organisms, on its metabolism, distribution, and accumulation in the organism, forms of fluoride in biological tissues, toxic effects of fluoride on physiological and reproductive functions of living organisms of various phylogenetic groups, as well as clinical symptoms of deficient and excessive fluoride intake into the human organism.

Synthesis, anti-inflammatory evaluation and docking studies of some new fluorinated fused quinazolines.

PubMed

Balakumar, C; Lamba, P; Kishore, D Pran; Narayana, B Lakshmi; Rao, K Venkat; Rajwinder, K; Rao, A Raghuram; Shireesha, B; Narsaiah, B

2010-11-01

A series of novel 8/10-trifluoromethyl-substituted-imidazo[1,2-c] quinazolines have been synthesized and evaluated in vivo (rat paw edema) for their anti-inflammatory activity and in silico (docking studies) to recognize the hypothetical binding motif of the title compounds with the cyclooxygenase isoenzymes (COX-1 and COX-2) employing GOLD (CCDC, 4.0.1 version) software. The compounds, 9b and 10b, were found to have good anti-inflammatory activity [around 80% of the standard: indomethacin]. The binding mode of the title compounds has been proposed based on the docking studies. Crown Copyright © 2010. Published by Elsevier Masson SAS. All rights reserved.

Evaluation of polar organic chemical integrative and hollow fibre samplers for the determination of a wide variety of organic polar compounds in seawater.

PubMed

Mijangos, Leire; Ziarrusta, Haizea; Prieto, Ailette; Zugazua, Oihane; Zuloaga, Olatz; Olivares, Maitane; Usobiaga, Aresatz; Paschke, Albrecht; Etxebarria, Nestor

2018-08-01

The calibration of two passive samplers for the determination of 20 emerging organic compounds in seawater is described in this work: i) a new version of polar organic chemical integrative sampler (POCIS) containing 100 mg of mixed-mode anion exchanger (Strata X-AW) and 100 mg of polymeric HLB (Plexa) sorbent materials and using a highly porous Nylon membrane (30-μm pore size) and ii) polyethersulfone (PES) hollow fibre. Among the studied contaminants, herbicides, hormones, life style products (stimulants and artificial sweeteners), industrial chemicals (corrosion inhibitor and fluorinated compounds), personal care products and several pharmaceuticals were included. In the case of POCIS, both the sorbents and the Nylon membranes were extracted and analysed independently. The calibration set up consisted on a continuous-flow tank that was fed with a continuous flow of seawater (2 L/h) and a stock mixture of contaminants (20 mL/h), assuring a nominal concentration of ~ 600 ng/L (each analyte) in the tank. The uptake was linear in POCIS sorbent and Nylon membranes but exponential for PES hollow fibres. Furthermore, the highest sampling rates (Rs) values were obtained in POCIS sorbent (between 2.7 for acetaminophen and 491 mL/day for perfluoro-n-octanoic acid, PFOA) followed by Nylon membranes (between 3.6 for OBT and 50 mL/day for telmisartan) and the lowest were those from PES fibres (between 1.7 for bezafibrate and 157 mL/day for butylparaben). Additionally, five deuterated compounds ([ 2 H 5 ]-atrazine, [ 2 H 3 ]-amitriptyline, [ 2 H 7 ]-irbesartan, [ 2 H 3 ]-ketoprofen and [ 2 H 9 ]-progesterone) were studied as candidates for performance reference compounds (PRCs) in both POCIS and PES, and though [ 2 H 5 ]-atrazine, [ 2 H 9 ]-progesterone and [ 2 H 3 ]-amitriptyline showed acceptable results in the case of POCIS, only [ 2 H 5 ]-atrazine provided a good validation. In the case of PES fibres, the PRC corrections did not provide acceptable results due to a low dissipation of the PRCs. Finally, POCIS were deployed in two sites of the low part of the estuary of Bilbao (northern Spain) from where water samples were also taken and analysed. As a result, in addition to the overall good agreement between the passive and active samplings, passive samplers allowed the determination of several compounds that were below the detection limits in the active sampling. Copyright © 2018. Published by Elsevier B.V.

Synthesis and evaluation of 18F-labeled ATP competitive inhibitors of topoisomerase II as probes for imaging topoisomerase II expression

PubMed Central

Daumar, Pierre; Zeglis, Brian M.; Ramos, Nicholas; Divilov, Vadim; Sevak, Kuntal Kumar; Pillarsetty, NagaVaraKishore; Lewis, Jason S.

2015-01-01

Type II topoisomerase (Topo-II) is an ATP-dependent enzyme that is essential in the transcription, replication, and chromosome segregation processes and, as such, represents an attractive target for cancer therapy. Numerous studies indicate that the response to treatment with Topo-II inhibitors is highly dependent on both the levels and the activity of the enzyme. Consequently, a non-invasive assay to measure tumoral Topo-II levels has the potential to differentiate responders from non-responders. With the ultimate goal of developing a radiofluorinated tracer for positron emission tomography (PET) imaging, we have designed, synthesized, and evaluated a set of fluorinated compounds based on the structure of the ATP-competitive Topo-II inhibitor QAP1. Compounds 18 and 19b showed inhibition of Topo-II in in vitro assays and exhibited moderate, Topo-II level dependent cytotoxicity in SK-BR-3 and MCF-7 cell lines. Based on these results, 18F-labeled analogs of these two compounds were synthesized and evaluated as PET probes for imaging Topo-II overexpression in mice bearing SK-BR-3 xenografts. [18F]-18 and [18F]-19b were synthesized from their corresponding protected tosylated derivatives by fluorination and subsequent deprotection. Small animal PET imaging studies indicated that both compounds do not accumulate in tumors and exhibit poor pharmacokinetics, clearing from the blood pool very rapidly and getting metabolized over. The insights gained from the current study will surely aid in the design and construction of future generations of PET agents for the non-invasive delineation of Topo-II expression. PMID:25240701

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jordan, A.; Harnisch, J.; Borchers, R.

Previous investigations reported on the volcanic production of halocarbons including chlorofluorocarbons (CFCs). It has been suggested that this natural source could account for a significant atmospheric CFC background concentration, but no quantitative assessment of its source strength has yet been presented. The synthetic mechanism for their volcanic formation has neither been clarified. Fumarole and lava gas samples from four volcanoes (Kuju, Satsuma Iwojima, Mt. Etna, Vulcano) have been studied using gas chromatography/ion trap-mass spectrometry. More than 300 organic substances were detected, among which 5 fluorinated, 100 chlorinated, 25 brominated, and 4 iodinated compounds have been identified. The most abundant organohalogenmore » species were chlorinated methanes, unsaturated C{sub 2}-chlorohydrocarbons, and chlorobenzene, suggesting a synthetic course that includes the thermolytic formation of acetylene from hydrothermal methane, condensation reactions, and synchronous catalytic halogenation in the presence of highly activated surfaces of cooling magma or juvenile ash. The only CFC compound found was CFCl{sub 3} (CFC-11), which was detected in some samples at concentrations of up to 1 ppbv. A conservative estimate of the upper limit of global CFC emissions by volcanoes clearly shows that this source is negligible as compared to the atmospheric burden by anthropogenic activities.« less

Carbon-11 and fluorine-18 chemistry devoted to molecular probes for imaging the brain with positron emission tomography.

PubMed

Dollé, Frédéric

2013-01-01

Exploration of the living human brain in real-time and in a noninvasive way was for centuries only a dream, made, however, possible today with the remarkable development during the four last decades of powerful molecular imaging techniques, and especially positron emission tomography (PET). Molecular PET imaging relies, from a chemical point of view, on the use and preparation of a positron-emitting radiolabelled probe or radiotracer, notably compounds incorporating one of two short-lived radionuclides fluorine-18 (T1/2 : 109.8 min) and carbon-11 (T1/2 : 20.38 min). The growing availability and interest for the radiohalogen fluorine-18 in radiopharmaceutical chemistry undoubtedly results from its convenient half-life and the successful use in clinical oncology of 2-[(18) F]fluoro-2-deoxy-d-glucose ([(18) F]FDG). The special interest of carbon-11 is not only that carbon is present in virtually all biomolecules and drugs allowing therefore for isotopic labelling of their chemical structures but also that a given molecule could be radiolabelled at different functions or sites, permitting to explore (or to take advantage of) in vivo metabolic pathways. PET chemistry includes production of these short-lived radioactive isotopes via nuclear transmutation reactions using a cyclotron, and is directed towards the development of rapid synthetic methods, at the trace level, for the introduction of these nuclides into a molecule, as well as the use of fast purification, analysis and formulation techniques. PET chemistry is the driving force in molecular PET imaging, and this special issue of the Journal of Labelled Compounds and Radiopharmaceuticals, which is strongly chemistry and radiochemistry-oriented, aims at illustrating, be it in part only, the state-of-the-art arsenal of reactions currently available and its potential for the research and development of specific molecular probes labelled with the positron emitters carbon-11 and fluorine-18, with optimal imaging properties for PET exploration of the brain. Copyright © 2013 John Wiley & Sons, Ltd.

Incompletely-Condensed Fluoroalkyl Silsesquioxanes and Derivatives: Precursors for Low Surface Energy Materials (Preprint)

DTIC Science & Technology

2011-09-13

superhydrophobic and oleophobic materials. Utilizing triflic acid, open-cage compounds were created and then reacted with a variety of dichlorosilanes...fluorinated nanobuilding blocks with a controlled level of reactive functionality for the development of new superhydrophobic and oleophobic...F-POSS), which are useful as low surface energy materials for superhydrophobic and oleophobic materials. Utilizing triflic acid, open-cage

The Physical Properties of a Lavage Mixture of Pulmonary Surfactant, Perfluorodecaline, and Methylprednisolone (Perfactant Lavage)

DTIC Science & Technology

2014-05-09

release: distribution unlimited Purpose: To characterize the physical properties of a lavage mixture of pulmonary surfactant, perfluorocarbon and...methylprednisolone. Background: Perfluorocarbons (PFCs) are compounds derived from hydrocarbons by the substitution of hydrogen atoms with fluorine...atoms. Perfluorocarbon liquids are colorless, odorless and biologically inert. They are highly dense, due to their molecular weight. Their low

Effect of fluorine substitution on the interaction of lipophilic ions with the plasma membrane of mammalian cells.

PubMed Central

Kürschner, M; Nielsen, K; von Langen, J R; Schenk, W A; Zimmermann, U; Sukhorukov, V L

2000-01-01

The effects of the anionic tungsten carbonyl complex [W(CO)(5)SC(6)H(5)](-) and its fluorinated analog [W(CO)(5)SC(6)F(5)](-) on the electrical properties of the plasma membrane of mouse myeloma cells were studied by the single-cell electrorotation technique. At micromolar concentrations, both compounds gave rise to an additional antifield peak in the rotational spectra of cells, indicating that the plasma membrane displayed a strong dielectric dispersion. This means that both tungsten derivatives act as lipophilic ions that are able to introduce large amounts of mobile charges into the plasma membrane. The analysis of the rotational spectra allowed the evaluation not only of the passive electric properties of the plasma membrane and cytoplasm, but also of the ion transport parameters, such as the surface concentration, partition coefficient, and translocation rate constant of the lipophilic anions dissolved in the plasma membrane. Comparison of the membrane transport parameters for the two anions showed that the fluorine-substituted analog was more lipophilic, but its translocation across the plasma membrane was slower by at least one order of magnitude than that of the parent hydrogenated anion. PMID:10969010

Synthesis of novel acid electrolytes for phosphoric acid fuel cells

NASA Astrophysics Data System (ADS)

Adcock, James L.

1988-11-01

A 40 millimole per hour scale aerosol direct fluorination reactor was constructed. F-Methyl F-4-methoxybutanoate and F-4-methoxybutanoyl fluoride were synthesized by aerosol direct fluorination of methyl 4-methoxybutanoate. Basic hydrolysis of the perfluorinated derivatives produce sodium F-4 methoxybutanoate which was pyrolyzed to F-3-methoxy-1-propene. Purification and shipment of 33 grams of F-3-methoxy-1-propene followed. Syntheses by analogous methods allowed production and shipment of 5 grams of F-3-ethoxy 1-propene, 18 grams of F-3-(2-methoxy.ethoxy) 1-propene, and 37 grams of F-3,3-dimethyl 1-butene. Eighteen grams of F-2,2-dimethyl 1-chloropropane was produced directly and shipped. As suggested by other contractors, 5 grams of F-3-methoxy 1-iodopropane, and 5 grams of F-3-(2-methoxy.ethoxy) 1-iodopropane were produced by converting the respective precursor acid sodium salts produced for olefin synthesis to the silver salts and pyrolyzing them with iodine. Each of these compounds was prepared for the first time by the aerosol fluorination process during the course of the contract. These samples were provided to other Gas Research Institute (GRI) contractors for synthesis of perfluorinated sulfur (VI) and phosphorous (V) acids.

Quantitative analysis of sitagliptin using the (19)F-NMR method: a universal technique for fluorinated compound detection.

PubMed

Zhang, Fen-Fen; Jiang, Meng-Hong; Sun, Lin-Lin; Zheng, Feng; Dong, Lei; Shah, Vishva; Shen, Wen-Bin; Ding, Ya

2015-01-07

To expand the application scope of nuclear magnetic resonance (NMR) technology in quantitative analysis of pharmaceutical ingredients, (19)F nuclear magnetic resonance ((19)F-NMR) spectroscopy has been employed as a simple, rapid, and reproducible approach for the detection of a fluorine-containing model drug, sitagliptin phosphate monohydrate (STG). ciprofloxacin (Cipro) has been used as the internal standard (IS). Influential factors, including the relaxation delay time (d1) and pulse angle, impacting the accuracy and precision of spectral data are systematically optimized. Method validation has been carried out in terms of precision and intermediate precision, linearity, limit of detection (LOD) and limit of quantification (LOQ), robustness, and stability. To validate the reliability and feasibility of the (19)F-NMR technology in quantitative analysis of pharmaceutical analytes, the assay result has been compared with that of (1)H-NMR. The statistical F-test and student t-test at 95% confidence level indicate that there is no significant difference between these two methods. Due to the advantages of (19)F-NMR, such as higher resolution and suitability for biological samples, it can be used as a universal technology for the quantitative analysis of other fluorine-containing pharmaceuticals and analytes.

An investigation of the structure and bond rotational potential of some fluorinated ethanes by NMR spectroscopy of solutions in nematic liquid crystalline solvents.

PubMed

Emsley, J W; Longeri, M; Merlet, D; Pileio, G; Suryaprakash, N

2006-06-01

NMR spectra of 1,2-dibromo-1,1-difluoroethane and 1-bromo-2-iodo-tetrafluoroethane dissolved in nematic liquid crystalline solvents have been analysed to yield the magnitudes and signs of the scalar couplings, J(ij), and total anisotropic couplings, T(ij), between all the (1)H, (19)F, and (13)C nuclei, except for those between two (13)C nuclei. The values obtained for T(ij) in principle contain a contribution from J(ij)(aniso), the component along the static applied magnetic field of the anisotropic part of the electron-mediated spin-spin coupling. Neglecting this contribution allows partially averaged dipolar couplings, D(ij), to be extracted from the T(ij), and these were used to determine the structure, orientational order, and the conformational distribution generated by rotation about the C-C bond. The values obtained are compared with the results of calculations by ab initio and density functional methods. The differences found are no greater than those obtained for similar compounds which do not contain fluorine, so that there is no definitive evidence for significant contributions from J(CF)(aniso) or J(FF)(aniso) in the two compounds studied.

An investigation of the structure and bond rotational potential of some fluorinated ethanes by NMR spectroscopy of solutions in nematic liquid crystalline solvents

NASA Astrophysics Data System (ADS)

Emsley, J. W.; Longeri, M.; Merlet, D.; Pileio, G.; Suryaprakash, N.

2006-06-01

NMR spectra of 1,2-dibromo-1,1-difluoroethane and 1-bromo-2-iodo-tetrafluoroethane dissolved in nematic liquid crystalline solvents have been analysed to yield the magnitudes and signs of the scalar couplings, Jij, and total anisotropic couplings, Tij, between all the 1H, 19F, and 13C nuclei, except for those between two 13C nuclei. The values obtained for Tij in principle contain a contribution from Jijaniso, the component along the static applied magnetic field of the anisotropic part of the electron-mediated spin-spin coupling. Neglecting this contribution allows partially averaged dipolar couplings, Dij, to be extracted from the Tij, and these were used to determine the structure, orientational order, and the conformational distribution generated by rotation about the C-C bond. The values obtained are compared with the results of calculations by ab initio and density functional methods. The differences found are no greater than those obtained for similar compounds which do not contain fluorine, so that there is no definitive evidence for significant contributions from JCFaniso or JFFaniso in the two compounds studied.

Particle size distribution of aerosols sprayed from household hand-pump sprays containing fluorine-based and silicone-based compounds.

PubMed

Kawakami, Tsuyoshi; Isama, Kazuo; Ikarashi, Yoshiaki

2015-01-01

Japan has published safety guideline on waterproof aerosol sprays. Furthermore, the Aerosol Industry Association of Japan has adopted voluntary regulations on waterproof aerosol sprays. Aerosol particles of diameter less than 10 µm are considered as "fine particles". In order to avoid acute lung injury, this size fraction should account for less than 0.6% of the sprayed aerosol particles. In contrast, the particle size distribution of aerosols released by hand-pump sprays containing fluorine-based or silicone-based compounds have not been investigated in Japan. Thus, the present study investigated the aerosol particle size distribution of 16 household hand-pump sprays. In 4 samples, the ratio of fine particles in aerosols exceeded 0.6%. This study confirmed that several hand-pump sprays available in the Japanese market can spray fine particles. Since the hand-pump sprays use water as a solvent and their ingredients may be more hydrophilic than those of aerosol sprays, the concepts related to the safety of aerosol-sprays do not apply to the hand pump sprays. Therefore, it may be required for the hand-pump spray to develop a suitable method for evaluating the toxicity and to establish the safety guideline.

Synthesis and biological evaluation of ¹⁸F-labeled fluoropropyl tryptophan analogs as potential PET probes for tumor imaging.

PubMed

Chiotellis, Aristeidis; Mu, Linjing; Müller, Adrienne; Selivanova, Svetlana V; Keller, Claudia; Schibli, Roger; Krämer, Stefanie D; Ametamey, Simon M

2013-01-01

In the search for an efficient, fluorine-18 labeled amino acid based radiotracer for tumor imaging with positron emission tomography (PET), two new tryptophan analogs were synthesized and characterized in vitro and in vivo. Both are tryptophan alkyl-derivatives, namely 2-(3-[(18)F]fluoropropyl)-DL-tryptophan ([(18)F]2-FPTRP) and 5-(3-[(18)F]fluoro-propyl)-DL-tryptophan ([(18)F]5-FPTRP). Standard reference compounds and precursors were prepared by multi step approaches. Radiosynthesis was achieved by no-carrier-added nucleophilic [(18)F]fluorination in 29-34% decay corrected yields with radiochemical purity over 99%. In vitro cell uptake assays showed that both compounds are substrates for amino acid transport and enter small cell lung cancer cells (NCI-H69) most probably almost exclusively via large neutral amino acids transporter(s) (LAT). Small animal PET imaging with xenograft bearing mice revealed high tumor/background ratios for [(18)F]2-FPTRP comparable to the well established tyrosine analog O-(2-[(18)F]fluroethyl)-L-tyrosine ([(18)F]FET). Radiometabolite studies showed no evidence of involvement of a biotransformation step in tumor accumulation. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Testing odorants recovery from a novel metallized fluorinated ethylene propylene gas sampling bag.

PubMed

Zhu, Wenda; Koziel, Jacek A; Cai, Lingshuang; Wright, Donald; Kuhrt, Fred

2015-12-01

Industry-standard Tedlar bags for odor sample collection from confined animal feeding operations (CAFOs) have been challenged by the evidence of volatile organic compound (VOC) losses and background interferences. Novel impermeable aluminum foil with a thin layer of fluorinated ethylene propylene (FEP) film on the surface that is in contact with a gas sample was developed to address this challenge. In this research, Tedlar and metallized FEP bags were compared for (a) recoveries of four characteristic CAFO odorous VOCs (ethyl mercaptan, butyric acid, isovaleric acid and p-cresol) after 30 min and 24 hr sample storage time and for (b) chemical background interferences. All air sampling and analyses were performed with solid-phase microextraction (SPME) followed by gas chromatography-mass spectroscopy (GC-MS). Mean target gas sample recoveries from metallized FEP bags were 25.9% and 28.0% higher than those in Tedlar bags, for 30 min and 24 hr, respectively. Metallized FEP bags demonstrated the highest p-cresol recoveries after 30-min and 24-hr storage, 96.1±44.5% and 44.8±10.2%, respectively, among different types of sampling bags reported in previous studies. However, a higher variability was observed for p-cresol recovery with metallized FEP bags. A 0% recovery of ethyl mercaptan was observed with Tedlar bags after 24-hr storage, whereas an 85.7±7.4% recovery was achieved with metallized FEP bags. Recoveries of butyric and isovaleric acids were similar for both bag types. Two major impurities in Tedlar bags' background were identified as N,N-dimethylacetamide and phenol, while backgrounds of metallized FEP bags were significantly cleaner. Reusability of metallized FEP bags was tested. Caution is advised when using polymeric materials for storage of livestock-relevant odorous volatile organic compounds. The odorants loss with storage time confirmed that long-term storage in whole-air form is ill advised. A focused short-term odor sample containment should be biased toward the most inert material available relative to the highest impact target odorant. Metallized FEP was identified as such a material to p-cresol as the highest impact odorant from confined animal feeding operations. Metallized FEP bags have much cleaner background than commercial Tedlar bags do. Significantly higher recoveries of methyl mercaptan and p-cresol were also observed with metallized FEP bags.

Processing liquid organic wastes at the NNL Preston laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coppersthwaite, Duncan; Greenwood, Howard; Docrat, Tahera

2013-07-01

Organic compounds of various kinds have been used in the nuclear industry for numerous duties in uranium chemical, metal and ceramic processing plants. In the course of the various operations undertaken, these organic compounds have become contaminated with uranic material, either accidentally or as an inevitable part of the process. Typically, the chemical/physical form and/or concentration of the uranic content of the organics has prevented disposal. In order to address the issue of contaminated liquid organic wastes, the National Nuclear Laboratory (NNL) has developed a suite of treatments designed to recover uranium and to render the waste suitable for disposal.more » The developed processes are operated at industrial scale via the NNL Preston Laboratory Residue Processing Plant. The Oil Waste Leaching (OWL) Process is a fully industrialised process used for the treatment of contaminated oils with approximately 200 tonnes of uranium contaminated oil being treated to date. The process was originally developed for the treatment of contaminated tributyl phosphate and odourless kerosene which had been adsorbed onto sawdust. However, over the years, the OWL process has been refined for a range of oils including 'water emulsifiable' cutting oils, lubricating oils, hydraulic oils/fluids and 'Fomblin' (fully fluorinated) oils. Chemically, the OWL process has proved capable of treating solvents as well as oils but the highly volatile/flammable nature of many solvents has required additional precautions compared with those required for oil treatment. These additional precautions led to the development of the Solvent Treatment Advanced Rig (STAR), an installation operated under an inert atmosphere. STAR is a small 'module' (100 dm{sup 3} volume) which allows the treatment of both water miscible and immiscible solvents. This paper discusses the challenges associated with the treatment of liquid organic wastes and the process developments which have allowed a wide range of materials to be successfully treated. (authors)« less

Improved organic p-i-n type solar cells with n-doped fluorinated hexaazatrinaphthylene derivatives HATNA-F{sub 6} and HATNA-F{sub 12} as transparent electron transport material

DOE Office of Scientific and Technical Information (OSTI.GOV)

Selzer, Franz, E-mail: franz.selzer@iapp.de; Falkenberg, Christiane, E-mail: Christiane.Falkenberg@heliatek.com; Leo, Karl, E-mail: karl.leo@iapp.de

2014-02-07

We study new electron transport materials (ETM) to replace the reference material C{sub 60} in p-i-n type organic solar cells. A comprehensive material characterization is performed on two fluorinated hexaazatrinaphthylene derivatives, HATNA-F{sub 6} and HATNA-F{sub 12}, to identify the most promising material for the application in devices. We find that both HATNA derivatives are equally able to substitute C{sub 60} as ETM as they exhibit large optical energy gaps, low surface roughness, and sufficiently high electron mobilities. Furthermore, large electron conductivities of 3.5×10{sup −5} S/cm and 2.0×10{sup −4} S/cm are achieved by n-doping with 4 wt. % W{sub 2}(hpp){sub 4}. HOMO levels of (7.72 ± 0.05) eVmore » and (7.73 ± 0.05) eV are measured by ultraviolet photoelectron spectroscopy and subsequently used for estimating LUMO values of (4.2 ± 0.8) eV and (4.3 ± 0.8) eV. Both fluorinated HATNA derivatives are successfully applied in p-i-n type solar cells. Compared to identical reference devices comprising the standard material C{sub 60}, the power conversion efficiency (PCE) can be increased from 2.1 % to 2.4 % by using the new fluorinated HATNA derivatives.« less

Application of Shear Plate Interferometry to Jet Diffusion Flame Temperature Measurements

NASA Technical Reports Server (NTRS)

VanDerWege, Brad A.; OBrien, Chris J.; Hochgreb, Simone

1997-01-01

The recent ban on the production of bromotrifluoromethane (CF3Br) because of its high stratospheric ozone depletion potential has led to interest in finding alternative agents for fire extinguishing applications. Some of the promising alternatives are fluorinated hydrocarbons. A clear understanding of the effects of CF3Br and alternative chemical suppressants on diffusion flames is therefore necessary in the selection of alternative suppressants for use in normal and microgravity. The flame inhibition effects of halogen compounds have been studied extensively in premixed systems. The effect of addition of halocarbons (carbon-halogen compounds) to diffusion flames has been studied experimentally in coflow configurations and in counterflow gaseous and liquid-pool flames. Halogenated compounds are believed to inhibit combustion by scavenging hydrogen radicals to form the relatively unreactive compound HF, or through a catalytic recombination cycle involving HBr to form H2. Comparisons between halogens show that bromine inhibition is significantly more effective than chlorine or fluorine. Although fluorinated compounds are only slightly more effective inhibitors on a mass basis than nitrogen, they are more effective on a volume basis and are easily stored in liquid form. The objectives of this study are (a) to determine the stability limits of laminar jet diffusion flames with respect to inhibitor concentration in both normal and microgravity, and (b) to investigate the structure of halocarbon-inhibited flames. In the initial phase of this project, visual diagnostics were used to observe the structure and behavior of normal and microgravity flames. The initial observations showed significant changes in the structure of the flames with the addition of halocarbons to the surrounding environment, as discussed below. Furthermore, the study established that the flames are more stable relative to the addition of halocarbons in microgravity than in normal gravity. Visual diagnostics of flames are, however, necessarily limited to detection of radiative emission in the visible range, and offer only qualitative information about the nature of the processes in the flame. In particular, the study sought to understand the structure of the inhibitor-perturbed flames with regard to temperature and species concentration in the outer region of the flame. Whereas thermocouple measurements can be used in ground based studies, their implementation in drop-tower rigs is limited. A possible approach to determine the temperature field around the flame is to use interferometric techniques. The implementation and testing of a shear-plate interferometry technique is described below.

Printable elastic conductors with a high conductivity for electronic textile applications

PubMed Central

Matsuhisa, Naoji; Kaltenbrunner, Martin; Yokota, Tomoyuki; Jinno, Hiroaki; Kuribara, Kazunori; Sekitani, Tsuyoshi; Someya, Takao

2015-01-01

The development of advanced flexible large-area electronics such as flexible displays and sensors will thrive on engineered functional ink formulations for printed electronics where the spontaneous arrangement of molecules aids the printing processes. Here we report a printable elastic conductor with a high initial conductivity of 738 S cm−1 and a record high conductivity of 182 S cm−1 when stretched to 215% strain. The elastic conductor ink is comprised of Ag flakes, a fluorine rubber and a fluorine surfactant. The fluorine surfactant constitutes a key component which directs the formation of surface-localized conductive networks in the printed elastic conductor, leading to a high conductivity and stretchability. We demonstrate the feasibility of our inks by fabricating a stretchable organic transistor active matrix on a rubbery stretchability-gradient substrate with unimpaired functionality when stretched to 110%, and a wearable electromyogram sensor printed onto a textile garment. PMID:26109453

Fluorine-containing composition for forming anti-reflection film on resist surface and pattern formation method

DOEpatents

Nishi, Mineo; Makishima, Hideo

1996-01-01

A composition for forming anti-reflection film on resist surface which comprises an aqueous solution of a water soluble fluorine compound, and a pattern formation method which comprises the steps of coating a photoresist composition on a substrate; coating the above-mentioned composition for forming anti-reflection film; exposing the coated film to form a specific pattern; and developing the photoresist, are provided. Since the composition for forming anti-reflection film can be coated on the photoresist in the form of an aqueous solution, not only the anti-reflection film can be formed easily, but also, the film can be removed easily by rinsing with water or alkali development. Therefore, by the pattern formation method according to the present invention, it is possible to form a pattern easily with a high dimensional accuracy.

Structure of 1,5-benzodiazepinones in the solid state and in solution: Effect of the fluorination in the six-membered ring

PubMed Central

Pérez-Torralba, Marta; Ángeles García, M; López, Concepción; Torralba, M Carmen; Rosario Torres, M; Alkorta, Ibon; Elguero, José

2013-01-01

Summary Two novel tetrafluorinated 1,5-benzodiazepinones were synthesized and their X-ray structures determined. 6,7,8,9-Tetrafluoro-4-methyl-1,3-dihydro-2H-1,5-benzodiazepin-2-one crystallizes in the monoclinic P21/c space group and 6,7,8,9-tetrafluoro-1,4-dimethyl-1,3-dihydro-2H-1,5-benzodiazepin-2-one in the triclinic P−1 space group. Density functional theory studies at the B3LYP/6-311++G(d,p) level were carried out on these compounds and on four non-fluorinated derivatives, allowing to calculate geometries, tautomeric energies and ring-inversion barriers, that were compared with the experimental results obtained by static and dynamic NMR in solution and in solid state. PMID:24204428

Synthesis and Late-Stage Functionalization of Complex Molecules through C–H Fluorination and Nucleophilic Aromatic Substitution

PubMed Central

2015-01-01

We report the late-stage functionalization of multisubstituted pyridines and diazines at the position α to nitrogen. By this process, a series of functional groups and substituents bound to the ring through nitrogen, oxygen, sulfur, or carbon are installed. This functionalization is accomplished by a combination of fluorination and nucleophilic aromatic substitution of the installed fluoride. A diverse array of functionalities can be installed because of the mild reaction conditions revealed for nucleophilic aromatic substitutions (SNAr) of the 2-fluoroheteroarenes. An evaluation of the rates for substitution versus the rates for competitive processes provides a framework for planning this functionalization sequence. This process is illustrated by the modification of a series of medicinally important compounds, as well as the increase in efficiency of synthesis of several existing pharmaceuticals. PMID:24918484

In situ gel-to-crystal transition and synthesis of metal nanoparticles obtained by fluorination of a cyclic β-aminoalcohol gelator.

PubMed

Xu, Yang; Kang, Chuanqing; Chen, Yu; Bian, Zheng; Qiu, Xuepeng; Gao, Lianxun; Meng, Qingxin

2012-12-21

A new fluorinated version of a cyclic β-aminoalcohol gelator derived from 1,2,3,4-tetrahydroisoquinoline is presented. The gelator is able to gel various nonprotic solvents through OH⋅⋅⋅N hydrogen bonds and additional CH⋅⋅⋅F interactions due to the introduction of fluorine. A bimolecular lamellar structure is formed in the gel phase, which partly preserves the pattern of molecular organization in the single crystal. The racemate of the chiral gelator shows lower gelation ability than its enantiomer because of a higher tendency to form microcrystals, as shown by X-ray diffraction analysis. The influence of fluorination on the self-assembly of the gelator and the properties of the gel was investigated in comparison to the original fluorine-free gel system. The introduction of fluorine brings two new features. The first is good recognition of o-xylene by the gelator, which induces an in situ transition from gels of o-xylene and of an o-xylene/toluene mixture to identical single crystals with unique tubular architecture. The second is the enhanced stability of the toluene gel towards ions, including quaternary ammonium salts, which enables the preparation of a stable toluene gel in the presence of chloroaurate or chloroplatinate. The gel system can be used as a template for the synthesis of spherical gold nanoparticles with a diameter of 5 to 9 nm and wormlike platinum nanostructures with a diameter of 2 to 3 nm and a length of 5 to 12 nm. This is the first example of a synthesis of platinum nanoparticles in an organogel medium. Therefore, the appropriate introduction of a fluorine atom and corresponding nonbonding interactions into a known gelator to tune the properties and functions of a gel is a simple and effective tactic for design of a gel system with specific targets. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Respiratory training during rehabilitation of acute organic fluorine-poisoned patients treated by non-invasive positive pressure ventilation.

PubMed

Liu, L; Liu, D Z; Wang, Q P; Zhu, Z L; Li, H M; Lu, X Y

2017-01-01

This paper aimed to analyze the effects of respiratory training on pulmonary function during the rehabilitation period for acute organic fluorine-poisoned patients treated by non-invasive positive pressure ventilation (NIPPV). Sixty-two acute organic fluorine-poisoned patients admitted to the Xinxiang Central Hospital, Xinxiang City, China, from May 2012 to March 2016 were selected and randomly divided into an observation group and a control group, with 31 cases in each. Both groups received NIPPV. The patients in the control group exercised daily, while the patients in the observation group received contracting lips-abdominal breathing training. The therapeutic effects, pulmonary ventilation function, serum levels of α-antitrypsin1 (α-AT1), surfactant protein D (SP-D), neutrophil elastase (NE), transforming growth factor beta 1 (TGF-β1), and quality of life were analyzed and compared between the two groups both before and after the administration of treatment. The total effective rate of the observation group was 93.55%, which was significantly higher when compared with the control group (74.19%) (P less than 0.05). The levels of forced expiratory volume in one second (FEV1), FEV1/FVC ratio, vital capacity (VC), carbon monoxide diffusion capacity (DLco), and maximal voluntary ventilation (MVV) of the observation group were better when compared with the control group and had statistical significance (P less than 0.05). Before treatment, the serum levels of α-AT1, SP-D, NE, and TGF-β1, and quality of life had no statistical significance in either group (P>0.05); after treatment, these indexes and the quality of life for the observation group were significantly higher when compared with the control group, with statistical significance (P less than 0.05). The respiratory training in acute organic fluorine-poisoned patients treated by NIPPV can improve the serum indexes, dilute toxicity, and recover pulmonary function, which play key roles in improving the therapeutic effects and quality of life of patients, and is worthy of clinical promotion.

Phosphorescent Iridium(III) Complexes Bearing Fluorinated Aromatic Sulfonyl Group with Nearly Unity Phosphorescent Quantum Yields and Outstanding Electroluminescent Properties.

PubMed

Zhao, Jiang; Yu, Yue; Yang, Xiaolong; Yan, Xiaogang; Zhang, Huiming; Xu, Xianbin; Zhou, Guijiang; Wu, Zhaoxin; Ren, Yixia; Wong, Wai-Yeung

2015-11-11

A series of heteroleptic functional Ir(III) complexes bearing different fluorinated aromatic sulfonyl groups has been synthesized. Their photophysical features, electrochemical behaviors, and electroluminescent (EL) properties have been characterized in detail. These complexes emit intense yellow phosphorescence with exceptionally high quantum yields (ΦP > 0.9) at room temperature, and the emission maxima of these complexes can be finely tuned depending upon the number of the fluorine substituents on the pendant phenyl ring of the sulfonyl group. Furthermore, the electrochemical properties and electron injection/transporting (EI/ET) abilities of these Ir(III) phosphors can also be effectively tuned by the fluorinated aromatic sulfonyl group to furnish some desired characters for enhancing the EL performance. Hence, the maximum luminance efficiency (ηL) of 81.2 cd A(-1), corresponding to power efficiency (ηP) of 64.5 lm W(-1) and external quantum efficiency (ηext) of 19.3%, has been achieved, indicating the great potential of these novel phosphors in the field of organic light-emitting diodes (OLEDs). Furthermore, a clear picture has been drawn for the relationship between their optoelectronic properties and chemical structures. These results should provide important information for developing highly efficient phosphors.

Synthesis of fluorine-18 radio-labeled serum albumins for PET blood pool imaging.

PubMed

Basuli, Falguni; Li, Changhui; Xu, Biying; Williams, Mark; Wong, Karen; Coble, Vincent L; Vasalatiy, Olga; Seidel, Jurgen; Green, Michael V; Griffiths, Gary L; Choyke, Peter L; Jagoda, Elaine M

2015-03-01

We sought to develop a practical, reproducible and clinically translatable method of radiolabeling serum albumins with fluorine-18 for use as a PET blood pool imaging agent in animals and man. Fluorine-18 radiolabeled fluoronicotinic acid-2,3,5,6-tetrafluorophenyl ester, [(18)F]F-Py-TFP was prepared first by the reaction of its quaternary ammonium triflate precursor with [(18)F]tetrabutylammonium fluoride ([(18)F]TBAF) according to a previously published method for peptides, with minor modifications. The incubation of [(18)F]F-Py-TFP with rat serum albumin (RSA) in phosphate buffer (pH9) for 15 min at 37-40 °C produced fluorine-18-radiolabeled RSA and the product was purified using a mini-PD MiniTrap G-25 column. The overall radiochemical yield of the reaction was 18-35% (n=30, uncorrected) in a 90-min synthesis. This procedure, repeated with human serum albumin (HSA), yielded similar results. Fluorine-18-radiolabeled RSA demonstrated prolonged blood retention (biological half-life of 4.8 hours) in healthy awake rats. The distribution of major organ radioactivity remained relatively unchanged during the 4 hour observation periods either by direct tissue counting or by dynamic PET whole-body imaging except for a gradual accumulation of labeled metabolic products in the bladder. This manual method for synthesizing radiolabeled serum albumins uses fluorine-18, a widely available PET radionuclide, and natural protein available in both pure and recombinant forms which could be scaled up for widespread clinical applications. These preclinical biodistribution and PET imaging results indicate that [(18)F]RSA is an effective blood pool imaging agent in rats and might, as [(18)F]HSA, prove similarly useful as a clinical imaging agent. Published by Elsevier Inc.

Mineralogical Studies Related to Endemic Diseases in Rural P. R. China

NASA Astrophysics Data System (ADS)

Belkin, H. E.; Zheng, B.; Finkelman, R. B.

2003-12-01

Domestic combustion of coal for heating and cooking is mostly confined to the world's developing countries and probably involves about 1 billion persons in China, India, Indonesia, and Africa. Various endemic diseases affecting millions of people involving arsenic, selenium, and fluorine poisoning have been associated with domestic coal combustion in rural China. We have investigated the relationship between mineralized coals (and stone coals) and disease occurrences in Guizhou and Hubei Provinces. The mineralogy of the coals has been studied by a wide variety of techniques, including optical petrography, scanning electron microscopy, electron microprobe analysis, ion probe, Synchrotron XANES-EXAFS, and Raman spectroscopy. Arsenic enrichment (up to 3 weight percent) in Upper Permian Longtan Formation coals, southwestern Guizhou Province, occurs in both 3+ and 5+ valence states. Arsenic occurs in arsenopyrite, pyrite, Al-phosphate, scorodite, Fe-oxides, and as an organically-bound species. Fluorine poisoning, much more widespread than arsenic-poisoning, is related to burning F-rich coals and F-rich clays as admixtures. Mineralogical and chemical analysis suggests that the clays contain the fluorine probably substituting for the hydroxyl group. Localized selenium poisoning in Hubei Province is related to Se-rich stone coals. The selenium occurs as a native element and in rare mandarinoite. In these three cases, knowledge of the paragenesis and mineralogy of the element enrichment in coal was vital to help understand and mitigate the endemic diseases. For the situation concerning arsenic and selenium poisoning, suspect coals have been identified and mining from these deposits has been curtailed. Fluorine has been a much more difficult problem for the local public health officials as both the coal and clay in the burning admixture can contain high fluorine. Regional geochemical and mineralogical studies will help to define coal and clay with low fluorine, suitable for domestic use.

SYNTHESIS AND STUDY OF HALOGENATED BENZYLAMIDES OF SOME ISOCYCLIC AND HETEROCYCLIC ACIDS AS POTENTIAL ANTICONVULSANTS.

PubMed

Strupińska, Marzanna; Rostafińska-Suchar, Grażyna; Pirianowicz-Chaber, Elżbieta; Grabczuk, Mateusz; Józwenko, Magdalena; Kowalczyk, Hubert; Szuba, Joanna; Wójcicka, Monika; Chen, Tracy; Mazurek, Aleksander P

2015-01-01

A series of potential anticonvulsants have been synthesized. There are eight fluorobenzylamides and three chlorobenzylamides of isocyclic or heterocyclic acids. Two not halogenated benzylamides were also synthesized to compare the effect of halogenation. The aim of the research performed was to evaluate whether halogenation of the mother structure is able to improve its anticonvulsant activity. The compounds were tested in Anticonvulsant Screening Project (ASP) of Antiepileptic Drug Development Program (ADDP) of NIH. Compound 1 showed MES ED50 = 80.32 mg/kg, PI = 3.16. Compound 7 showed CKM ED50 = 56.72 mg/kg. Compound 8 showed MES ED50 = 34.23 mg/kg and scPTZ ED50 > 300 mg/kg, PI = 8.53.Compound 13 showed 6Hz ED50 = 78.96, PI = 3.37. The results indicate that fluorination does not improve activity, whereas chlorination in our experiment even reduces it.

Docking studies on a new human immunodeficiency virus integrase-Mg-DNA complex: phenyl ring exploration and synthesis of 1H-benzylindole derivatives through fluorine substitutions.

PubMed

Ferro, Stefania; De Luca, Laura; Barreca, Maria Letizia; Iraci, Nunzio; De Grazia, Sara; Christ, Frauke; Witvrouw, Myriam; Debyser, Zeger; Chimirri, Alba

2009-01-22

A new model of HIV-1 integrase-Mg-DNA complex that is useful for docking experiments has been built. It was used to study the binding mode of integrase strand transfer inhibitor 1 (CHI-1043) and other fluorine analogues. Molecular modeling results prompted us to synthesize the designed derivatives which showed potent enzymatic inhibition at nanomolar concentration, high antiviral activity, and low toxicity. Microwave assisted organic synthesis (MAOS) was employed in several steps of the synthetic pathway, thus reducing reaction times and improving yields.

Synthesis and Structural Characterization of New High-Valent Inorganic Fluorine Compounds and their Oxidizing Properties. Volume 1

DTIC Science & Technology

1992-02-01

G.J. Schrobilgen, unpublished work. 48. A. Zalkin, D.L. Ward, R.N. Biagioni and D.H. Templeton, Inorg. Chem., 1978, 17, 1318. 49. N. Bartlett, B.G...Spcctrochiin. Acta 1960, 10, 505. 25. This work. 26. Zalkin. A., Ward. D.L.; Biagioni , R.N.; Templetoi, DIH.; Bartlett, N. Inorg. Chem. 1978, 17, 1318. 2.7

Materials investigation and tests for the development of space compatible electrical connectors

NASA Technical Reports Server (NTRS)

Pomeroy, C.; Mccabe, T.

1971-01-01

A molding study of compounds based on copolymers of highly fluorinated olefins and of flame retardant silicone is reported. Both single cavity and four cavity molds having size 22 and 24 holes with three webs in each hole were used. Also covered are dielectric strength, arc resistance, Bashore rebound, and maintenance aging tests on the various materials that have been successfully molded.

Comparative estimation of soil and plant pollution in the impact area of air emissions from an aluminium plant after technogenic load reduction.

PubMed

Evdokimova, Galina A; Mozgova, Natalya P

2015-01-01

The work provides a comparative analysis of changes in soil properties in the last 10-13 years along the pollution gradient of air emissions from Kandalaksha aluminium plant in connection with the reduction of their volume. The content of the priority pollutant fluorine (F) in atmospheric precipitation and in the organic horizon of soil in the plant impact zone significantly decreased in 2011-2013 compared to 2001. The aluminium concentrations reduced only in immediate proximity to the plant (2 km). The fluorine, calcium (Ca) and magnesium (Mg) concentrations are higher in liquid phase compared to solid phase thus these elements can migrated to greater distances from the pollution source (up to 15-20 km). Silicon (Si), aluminium (Al), iron (Fe) and phosphorus (P) can be found only in solid phases and in fall-out within the 5 km. The acidity of soil litter reduced by 2 pH units in the proximity to the plot within the 2 km. The zone of maximum soil contamination decreased from 2.5 km to 1.5 km from the emission source, the zones of heavy and moderate pollution reduced by 5 km in connection with the reduction of pollutant emissions in the plant. A high correlation between the fluorine concentrations in vegetables and litter was found. Higher fluorine concentrations in the soil result in its accumulation in plants. Mosses accumulate fluorine most intensively.

Sulfur hexafluoride plasma surface modification of Gly-Ala and Ala-Gly as Bombyx mori silk model compounds: Mechanism investigations

NASA Astrophysics Data System (ADS)

Sangprasert, W.; Lee, V. S.; Boonyawan, D.; Tashiro, K.; Nimmanpipug, P.

2010-01-01

Low-pressure plasma has been used to improve the hydrophobicity of Thai silk. In this study, Glycine-Alanine (GA) and Alanine-Glycine (AG) were chosen to represent model compounds of Bombyx mori silk. Single crystals of the simplified model compounds were characterized by polarizing microscopy and X-ray diffraction. The space groups of P2 12 12 1 and P2 1 were found for AG and GA, respectively. The initial structures for calculation were obtained from the experimental crystal structures. Density functional theory at the BHandHLYP levels was used to investigate possible mechanisms of fluorine radicals reacting with AG and GA in the SF 6 plasma treatment. The results indicate that hydrogen atoms of silk model compounds were most likely to be abstracted from the alanine residue.

An Eco-Friendly Ultrasound-Assisted Synthesis of Novel Fluorinated Pyridinium Salts-Based Hydrazones and Antimicrobial and Antitumor Screening

PubMed Central

Rezki, Nadjet; Al-Sodies, Salsabeel A.; Aouad, Mohamed R.; Bardaweel, Sanaa; Messali, Mouslim; El Ashry, El Sayed H.

2016-01-01

The present work reports an efficient synthesis of fluorinated pyridinium salts-based hydrazones under both conventional and eco-friendly ultrasound procedures. The synthetic approach first involves the preparation of halogenated pyridinium salts through the condensation of isonicotinic acid hydrazide (1) with p-fluorobenzaldehyde (2) followed by the nucleophilic alkylation of the resulting N-(4-fluorobenzylidene)isonicotinohydrazide (3) with a different alkyl iodide. The iodide counteranion of 5–10 was subjected to an anion exchange metathesis reaction in the presence of an excess of the appropriate metal salts to afford a new series of fluorinated pyridinium salts tethering a hydrazone linkage 11–40. Ultrasound irradiation led to higher yields in considerably less time than the conventional methods. The newly synthesized ILs were well-characterized with FT-IR, 1H NMR, 13C NMR, 11B, 19F, 31P and mass spectral analyses. The ILs were also screened for their antimicrobial and antitumor activities. Within the series, the salts tethering fluorinated counter anions 11–13, 21–23, 31–33 and 36–38 were found to be more potent against all bacterial and fungal strains at MIC 4–8 µg/mL. The in vitro antiproliferative activity was also investigated against four tumor cell lines (human ductal breast epithelial tumor T47D, human breast adenocarcinoma MCF-7, human epithelial carcinoma HeLa and human epithelial colorectal adenocarcinoma Caco-2) using the MTT assay, which revealed that promising antitumor activity was exhibited by compounds 5, 12 and 14. PMID:27213367

Thermal mineralization behavior of PFOA, PFHxA, and PFOS during reactivation of granular activated carbon (GAC) in nitrogen atmosphere.

PubMed

Watanabe, Nobuhisa; Takata, Mitsuyasu; Takemine, Shusuke; Yamamoto, Katsuya

2018-03-01

Waste disposal site is one of the important sinks of chemicals. A significant amount of perfluoroalkyl and polyfluoroalkyl substances (PFASs) such as perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and perfluorohexanoic acid (PFHxA) have been brought into it. Because of their aqueous solubility, PFASs are released to landfill effluent waters, from which PFASs are efficiently collected by adsorption technique using granular activated carbon (GAC). The exhausted GAC is reactivated by heating processes. The mineralization of PFASs during the reactivation process was studied. Being thermally treated in N 2 atmosphere, the recovery rate of mineralized fluorine and PFC homologues including short-chained perfluorocarboxylic acids was determined. If the reagent form of PFOA, PFHxA, and PFOS were treated at 700 °C, the recovery of mineralized fluorine was less than 30, 46, and 72 %, respectively. The rate increased to 51, 74, and 70 %, if PFASs were adsorbed onto GAC in advance; moreover, addition of excess sodium hydroxide (NaOH) improved the recovery to 74, 91, and 90 %. Residual PFAS homologue was less than 1 % of the original amount. Steamed condition did not affect destruction. The significant role of GAC was to suppress volatile release of PFASs from thermal ambient, whereas NaOH enhanced destruction and retained mineralized fluorine on the GAC surface. Comparing the recovery of mineralized fluorine, the degradability of PFOS was considered to be higher than PFOA and PFHxA. Whole mass balance missing 9~26 % of initial amount suggested formation of some volatile organofluoro compounds beyond analytical coverage.

Amphiphilic polymer based on fluoroalkyl and PEG side chains for fouling release coating

NASA Astrophysics Data System (ADS)

Cong, W. W.; Wang, K.; Yu, X. Y.; Zhang, H. Q.; Lv, Z.; Gui, T. J.

2017-12-01

Under static conditions, fouling release coating could not express good release property to marine organisms. Amphiphilic polymer with mixture of fluorinated monomer and short side group of polyethylene glycol (PEG) was synthesized. And also we studied the ability of amphiphilic polymer to influence the surface properties and how it controlled the adhesion of marine organisms to coated surfaces. By incorporating fluorinated monomer and PEG side chain into the polymer, the effect of incorporating both polar and non-polar groups on fouling-release coating could be studied. The dry surface was characterized by three-dimensional digital microscopy and scanning electron microscopy (SEM), and the morphology of the amphiphilic fouling release coating showed just like flaky petal. The amphiphilic polymer in fouling release coating tended to reconstruct in water, and the ability was examined by static contact angle, which was smaller than the PDMS (polydimethylsiloxane) fouling release coating. Also surface energy was calculated by three solvents, and surface energy of amphiphilic fouling release coating was higher than that of the PDMS fouling release coating. To understand more about its fouling release property, seawater exposure method was adopted in gulf of Qingdao port. Fewer diatoms Navicula were found in biofilm after using amphiphilic fouling release coating. In general, coating containing both PEG and fluorinated side chain possessed certain fouling release property.

Synthesis of isocryptolepine analogues and their structure-activity relationship studies as antiplasmodial and antiproliferative agents.

PubMed

Aroonkit, Pasuk; Thongsornkleeb, Charnsak; Tummatorn, Jumreang; Krajangsri, Suppachai; Mungthin, Mathirut; Ruchirawat, Somsak

2015-04-13

Novel isocryptolepine analogues have been conveniently synthesized and evaluated for antimalarial and antiproliferative activities. We have found 3-fluoro-8-bromo-isocryptolepine (1n) to have the highest activities against chloroquine-resistant K1, chloroquine-sensitive 3D7, and chloroquine- and mefloquine-resistant SKF58 and SRIV35 strains. Several fluorine-substituted analogues (1b, 1n, and 1q) also showed excellent selectivities while maintaining good to excellent activities against all four Plasmodium falciparum strains. Additionally, antiproliferative properties of isocryptolepine derivatives against HepG2, HuCCA-1, MOLT-3 and A549 cancer cell lines are reported for the first time in this study. 2-Chloroisocryptolepine (1c) and benzo-fused-2-chloroisocryptolepine (1i) showed significant bioactivities whereas several novel fluorinated compounds and 2-chloro-8-bromoisocryptolepine (1f) displayed excellent selectivities. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

SIMS depth profiling of working environment nanoparticles

NASA Astrophysics Data System (ADS)

Konarski, P.; Iwanejko, I.; Mierzejewska, A.

2003-01-01

Morphology of working environment nanoparticles was analyzed using sample rotation technique in secondary ion mass spectrometry (SIMS). The particles were collected with nine-stage vacuum impactor during gas tungsten arc welding (GTAW) process of stainless steel and shielded metal arc welding (SMAW) of mild steel. Ion erosion of 300-400 nm diameter nanoparticles attached to indium substrate was performed with 2 keV, 100 μm diameter, Ar + ion beam at 45° ion incidence and 1 rpm sample rotation. The results show that both types of particles have core-shell morphology. A layer of fluorine, chlorine and carbon containing compounds covers stainless steel welding fume particles. The cores of these particles are enriched in iron, manganese and chromium. Outer shell of mild steel welding fume particles is enriched in carbon, potassium, chlorine and fluorine, while the deeper layers of these nanoparticles are richer in main steel components.

Trifluorostyrene containing compounds, and their use in polymer electrolyte membranes

DOEpatents

Choudhury, Biswajit [Kingston, CA; Roelofs, Mark Gerrit [Hockessin, DE; Yang,; Zhen-Yu, [Hockessin, DE

2009-07-21

A fluorinated ion exchange polymer is prepared by grafting a monomer onto a base polymer, wherein the grafting monomer is selected from the group consisting of structure 1a, 1b and mixture thereof; ##STR00001## wherein Y is selected from the group consisting of --R.sub.FSO.sub.2F, --R.sub.FSO.sub.3M, --R.sub.SO.sub.2NH.sub.2 and --R.sub.FSO.sub.2N(M)SO.sub.2R.sup.2.sub.F, where in M is hydrogen, an alkali cation or ammonium; and R.sub.F and R.sup.2.sub.F are perfluorinated or partially fluorinated, and may optionally include ether oxygens; and n is between 1 and 2 for 1a, or n is between 1 and 3 for 1b. These ion exchange polymers are useful is preparing catalyst coated membranes and membrane electrode assemblies for fuel cells.

Fluorotelomer ethoxylates: sources of highly fluorinated environmental contaminants part I: biotransformation.

PubMed

Frömel, Tobias; Knepper, Thomas P

2010-09-01

Polyethoxylated 2-perfluoroalkylethanols ('fluorotelomer ethoxylates', F-(CF(2)-CF(2)-)(x)-(CH(2)-CH(2)-O)(y)-H, FTEO) are an important class of non-ionic fluorinated surfactants, which have been disregarded as potential source of per- and polyfluorinated organic pollutants despite their high production and application amounts. A commercial mixture of FTEO with a perfluoroalkyl chain length between 6 and 10 carbon atoms and an ethoxymer distribution between 0 and 13 was subjected to a biodegradation test. Monitoring of the aerobic biotransformation process by HPLC-ESI-MS/MS showed that FTEO are rapidly transformed with a half-life of approximately 1d. Structural elucidation of the biotransformation products with the help of hybrid quadrupole--linear ion trap tandem mass spectrometry revealed oxidation to the respective carboxylic acid followed by sequential shortening of ethoxylate units which led to FTEO carboxylates (FTEOC). The conversion rate of FTEOC was found to diminish with decreasing number of ethoxylate units and virtually ceased for compounds with seven intact ethoxy units. These short-chain FTEOC were not further degraded within 48d. Nonetheless, perfluorohexanoic acid (PFHxA) and perfluorooctanoic acid (PFOA) were detected, whose formation is ascribed to degradation of residual fluorotelomer alcohols present in the commercial product. This article represents the first of two parts of a series concerning FTEO. Whilst this part is clearly focused on results of a biodegradation study of FTEO, part two will pinpoint analytical aspects, synthesis of biotransformation products and first evidence of environmental presence of the biotransformation products. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Water, Water Everywhere but is it Safe to Drink? Some Detrimental Health Effects Associated with Consumption of Groundwater Enriched in Naturally-Occurring Contaminants

NASA Astrophysics Data System (ADS)

Fuge, R.

2007-05-01

Drinking water represents a major pathway of trace elements into the human body. As such, groundwaters, the chemistry of which reflect water/rock interaction, can be a source of trace elements which will have a marked health effect on humans consuming them. Health problems associated with the consumption of groundwater enriched in various elements and compounds have been recorded for many years. For example, high-arsenic groundwaters used for public water supply were first associated with harmful health effects as early as 1917 in Córdoba Province in Argentina, where the local population suffered from skin disorders. Subsequently, in the 1960s consumption of high-arsenic groundwaters was identified as a factor in the aetiology of "black foot disease", an endemic vascular disease, in Taiwan. However, it is problems associated with the very high-arsenic groundwaters of the highly populous Ganges delta area of Bangladesh and West Bengal that has more recently highlighted the health problem of consuming high-arsenic waters. The most obvious problems of excess arsenic consumption through drinking water are arsenical skin lesions, the severity of which being generally correlated with arsenic content of the water. A high incidence of cancers of the skin, bladder and other organs has been recorded in the high-arsenic drinking water areas of the world. A high incidence of vascular disease, found in the arsenic-rich area of Taiwan, has also been shown to occur in Bangladesh. In addition, it has been suggested that high arsenic in drinking water results in increased incidence of diabetes mellitus. Fluorine is another element long recognised as having a major effect on the well-being of humans. Consumption of high-fluorine waters were first identified as having a detrimental effect on teeth in the 1920s and 30s. It was subsequently shown that where fluorine is present in drinking waters at concentrations of around 0.5 to 1 mg/L it can have beneficial effects on humans, resulting in healthy teeth and bones. However, several areas of the world where potable waters derive from the ground, very high concentrations of fluorine, generally in excess of 4 mg/L have resulted in dental fluorosis and, at very high concentrations, crippling skeletal fluorosis. The detrimental effects of consuming elevated amounts of fluorine-rich drinking water are exacerbated by a poor, low-protein diet. Radioactive elements such as radon and uranium can be transported in groundwater. Domestic water supplies enriched in radon can in some areas represent a major pathway into humans, being released during showering etc, it can be inhaled and as such contributes to the incidence of lung cancer. In addition to the potential health problems of its radioactivity, uranium has been shown to be a nephrotoxin. High-uranium groundwaters consumed by humans over the short term can result in kidney damage.

Synthesis and bioactivities of halogen bearing phenolic chalcones and their corresponding bis Mannich bases.

PubMed

Yamali, Cem; Gul, Halise Inci; Sakagami, Hiroshi; Supuran, Claudiu T

2016-01-01

Phenolic bis Mannich bases having the chemical structure of 1-[3,5-bis-aminomethyl-4-hydroxyphenyl]-3-(4-halogenophenyl)-2-propen-1-ones (1a-c, 2a-c, 3a-c) were synthesized (Numbers 1, 2, and 3 represent fluorine, chlorine, and bromine bearing compounds, respectively, while a, b, and c letters represent the compounds having piperidine, morpholine, and N-methyl piperazine) and their cytotoxic and carbonic anhydrase (CA, EC 4.2.1.1) enzyme inhibitory effects were evaluated. Lead compounds should possess both marked cytotoxic potencies and selective toxicity for tumors. To reflect this potency, PSE values of the compounds were calculated. According to PSE values, the compounds 2b and 3b may serve as lead molecules for further anticancer drug candidate developments. Although the compounds showed a low inhibition potency toward hCA I (25-43%) and hCA II (6-25%) isoforms at 10 μM concentration of inhibitor, the compounds were more selective (1.5-5.2 times) toward hCA I isoenzyme. It seems that the compounds need molecular modifications for the development of better CA inhibitors.

Reaction of hydroxy and carbonyl compounds with sulfur tetrafluoride. XVI. Reactions of vicinal dihydric alcohols with sulfur tetrafluoride (in Russian)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burmakov, A.I.; Hassanein, S.M.; Kunshenko, B.V.

1986-11-20

During the action of sulfur tetrafluoride on ethanediol, d,l-1,2-propanediol, d,l-3,3,3-trifluoro-1,2-propanediol regioselective substitution of one of the hydroxyl groups by a fluorine atom occurs, depending on the electronic nature of the groups present in the molecule. The second hydroxy group in converted into a fluorosulfite group.

Surey of Alternate Stored Chemical Energy Reactions.

DTIC Science & Technology

1985-12-01

Fr., Report No. CEA-N-1293, 36 p. Pilipovich. D.; Rogers, H. H. and Wilson, R. D., 1972, Chlorine trifluoride oxide. II. Photochemical synthesis...some fluorine and chlorine compounds: Zh. Fiz. Khim., V. 43, No. 2, p. 386-9. Rogers, H. H. and Pilipovich, D., 1973, Oxychlorine trifluoride (Patent...chemical energy reactions has been made for purposes of comparison with the lithium- aluminum /water, lithium/sulfur hexafluoride, and other reaction schemes

Perovskite-like fluorides and oxyfluorides: Phase transitions and caloric effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flerov, I. N., E-mail: flerov@iph.krasn.ru; Gorev, M. V., E-mail: gorev@iph.krasn.ru; Tressaud, A.

2011-01-15

An analysis of the effect that chemical and hydrostatic pressures have on the thermodynamic properties of perovskite-like fluorine-oxygen compounds A{sub 2}A Prime MeO{sub x}F{sub 6-x} has revealed that materials under-going order-disorder transitions and having significant external-pressure compliance have the highest caloric efficiency. Some of the fluorides and oxyfluorides under study can be considered promising solid coolants.

Method for fluorinating coal

DOEpatents

Huston, John L.; Scott, Robert G.; Studier, Martin H.

1978-01-01

Coal is fluorinated by contact with fluorine gas at low pressure. After pial fluorination, when the reaction rate has slowed, the pressure is slowly increased until fluorination is complete, forming a solid fluorinated coal of approximate composition CF.sub.1.55 H.sub.0.15. The fluorinated coal and a solid distillate resulting from vacuum pyrolysis of the fluorinated coal are useful as an internal standard for mass spectrometric unit mass assignments from about 100 to over 1500.

Low Temperature Fluorination of Aerosol and Condensed Phase Sol Suspensions of Hydrocarbons Utilizing Elemental Fluorine.

DTIC Science & Technology

1980-10-01

NEOPENTANE FLUORINATIONS Ref. No. Structure Name NA F-C(CF3)3 perfluoroisobutane NB C (CF3)4. perfluoroneopentane 14 ,3 2 NC CFH-C(CF3)3...Photochemical Fluorination Fluorination Perfluorination El~mental Fluorine 20. APOWACT (Continue on rover** aide It necessary and identify by block...aerosol fluorinator capable of achieving high yields of perfluorinated hydrocarbons via a photo- chemical fluorination stage. The aerosol system also

Transport of organic solutes through amorphous teflon AF films.

PubMed

Zhao, Hong; Zhang, Jie; Wu, Nianqiang; Zhang, Xu; Crowley, Katie; Weber, Stephen G

2005-11-02

Fluorous media have great potential for selective extraction (e.g., as applied to organic synthesis). Fluorous polymer films would have significant advantages in fluorous separations. Stable films of Teflon AF 2400 were cast from solution. Films appear defect-free (SEM; AFM). Rigid aromatic solutes are transported (from chloroform solution to chloroform receiving phase) in a size-dependent manner (log permeability is proportional to -0.0067 times critical volume). Benzene's permeability is about 2 orders of magnitude higher than in comparable gas-phase experiments. The films show selectivity for fluorinated solutes in comparison to the hydrogen-containing control. Transport rates are dependent on the solvent making up the source and receiving phases. The effect of solvent is, interestingly, not due to changes in partition ratio, but rather it is due to changes in the solute diffusion coefficient in the film. Solvents plasticize the films. A less volatile compound, -COOH-terminated poly(hexafluoropropylene oxide) (4), plasticizes the films (T(g) = -40 degrees C). Permeabilities are decreased in comparison to 4-free films apparently because of decreased diffusivity of solutes. The slope of dependence of log permeability on critical volume is not changed, however.

Isolation and survey of novel fluoroacetate-degrading bacteria belonging to the phylum Synergistetes.

PubMed

Davis, Carl K; Webb, Richard I; Sly, Lindsay I; Denman, Stuart E; McSweeney, Chris S

2012-06-01

Microbial dehalogenation of chlorinated compounds in anaerobic environments is well known, but the degradation of fluorinated compounds under similar conditions has rarely been described. Here, we report on the isolation of a bovine rumen bacterium that metabolizes fluoroacetate under anaerobic conditions, the mode of degradation and its presence in gut ecosystems. The bacterium was identified using 16S rRNA gene sequence analysis as belonging to the phylum Synergistetes and was designated strain MFA1. Growth was stimulated by amino acids with greater quantities of amino acids metabolized in the presence of fluoroacetate, but sugars were not fermented. Acetate, formate, propionate, isobutryate, isovalerate, ornithine and H(2) were end products of amino acid metabolism. Acetate was the primary end product of fluoroacetate dehalogenation, and the amount produced correlated with the stoichiometric release of fluoride which was confirmed using fluorine nuclear magnetic resonance ((19) F NMR) spectroscopy. Hydrogen and formate produced in situ were consumed during dehalogenation. The growth characteristics of strain MFA1 indicated that the bacterium may gain energy via reductive dehalogenation. This is the first study to identify a bacterium that can anaerobically dehalogenate fluoroacetate. Nested 16S rRNA gene-specific PCR assays detected the bacterium at low numbers in the gut of several herbivore species. © 2012 Commonwealth of Australia.

Occurrence and source apportionment of Per- and poly-fluorinated compounds (PFCs) in North Canal Basin, Beijing

PubMed Central

Zhang, Yi-Zhe; Wang, Bin; Wang, Wei; Li, Wen-Chao; Huang, Jun; Deng, Shu-Bo; Wang, Yu-Jue; Yu, Gang

2016-01-01

Various per- and poly-fluorinated compounds (PFCs) were first systematically investigated in North Canal Basin, Beijing, China. A total of 68 surface water samples were collected from North Canal Basin, Beijing, at high spatial resolution. The seasonal disparity was compared and associated with source variation. PFCs concentrations in low-water period ranged from 26 to 207 ng/L, and significantly declined levels were found in high-water period. The individual component proportions among different sites varied less in high-water period, when runoff played a role in mixing and diluting PFCs. A methodology combined with principal component analysis (PCA), heat map-hierarchical cluster analysis (HM-HCA), and correlation analysis were introduced to discriminate sources of PFCs in surface water. The statistical results agreed with each other, and daily domestic consumption, fire-fighting products and related industries were identified as sources of PFCs in this region. In addition, two composition ratios were proposed through the methodology to distinguish the impact of nonpoint source, and the outcome demonstrates that great disparities exist in compositional profiles between nonpoint source and others. Overall, the results showed that this comprehensive analysis method has great potential for source apportionment in surface water and other environmental compartments. PMID:27845351

Structure-activity relationships of fluorinated dendrimers in DNA and siRNA delivery.

PubMed

Wang, Mingming; Cheng, Yiyun

2016-12-01

Fluorinated dendrimers have shown great promise in gene delivery due to their high transfection efficacy and low cytotoxicity, however, the structure-activity relationships of these polymers still remain unknown. Herein, we synthesized a library of fluorinated dendrimers with different dendrimer generations and fluorination degrees and investigated their behaviors in both DNA and siRNA delivery. The results show that fluorination significantly improves the transfection efficacy of G4-G7 polyamidoamine dendrimers in DNA and siRNA delivery. Fluorination on generation 5 dendrimer yields the most efficient polymers in gene delivery, and the transfection efficacy of fluorinated dendrimers depends on fluorination degree. All the fluorinated dendrimers cause minimal toxicity on the transfected cells at their optimal transfection conditions. This study provides a general and facile strategy to prepare high efficient and low cytotoxic gene carriers based on fluorinated polymers. The structure-activity relationships of fluorinated dendrimers in gene delivery is still unknown and the behavior of fluorinated dendrimers in siRNA delivery has not yet been investigated. Herein, we synthesized a library of fluorinated PAMAM dendrimers with different dendrimer generations and fluorination degrees and investigated their behaviors in both DNA and siRNA delivery. The results clearly indicate that fluorination significantly improves the transfection efficacy of dendrimers in both DNA and siRNA delivery without causing additional toxicity. G5 PAMAM dendrimer is best scaffold to synthesize fluorinated dendrimers and the transfection efficacy of fluorinated dendrimers depends on fluorination degree. This systematic study provides a general and facile strategy to prepare high efficient and low cytotoxic gene carriers based on fluorinated polymers. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Fluorine--a current literature review. An NRC and ATSDR based review of safety standards for exposure to fluorine and fluorides.

PubMed

Prystupa, Jeff

2011-02-01

A review of the literature of the element fluorine and its bonded-form, fluoride, was undertaken. Generally regarded as safe, an expanding body of literature reveals that fluoride's toxicity has been unappreciated, un-scrutinized, and hidden for over 70 years. The context for the literature search and review was an environmental climate-change study, which demonstrated widespread fluoride contamination by smokestack emissions from coal-fired electricity-generating plants. The objective of this review is to educate and inform regarding the ubiquitous presence and harmful nature of this now ever-present corrosive and reactive toxin. Methods include examination of national health agency reviews, primarily the National Research Council (NRC), Agency for Toxic Substances & Disease Registry (ATSDR), standard medical toxicology references, text books, as well as reports and documents from both private and public research as well as consumer-based NGOs. Study criteria were chosen for relevancy to the subject of the toxicity of fluoride. Fluoride is the extreme electron scavenger, the most corrosive of all elements, as well as the most-reactive. Fluoride appears to attack living tissues, via several mechanisms. Fluoride renders strong evidence that it is a non-biological chemical, demonstrating no observed beneficial function or role in organic chemistry, beyond use as a pesticide or insecticide. Fluorine has a strong role to play in industry, having been utilized extensively in metals, plastics, paints, aluminium, steel, and uranium production. Due to its insatiable appetite for calcium, fluorine and fluorides likely represent a form of chemistry that is incompatible with biological tissues and organ system functions. Based on an analysis of the affects of fluoride demonstrated consistently in the literature, safe levels have not been determined nor standardized. Mounting evidence presents conflicting value to its presence in biological settings and applications. Evidence examined in this review of the literature, and specifically the recent report by the National Research Council (NRC), offer strong support for an immediate reconsideration concerning risk vs benefit. Consensus recommendations from several sources are presented.

Gallium Compounds: A Possible Problem for the G2 Approaches

NASA Technical Reports Server (NTRS)

Bauschlicher, Charles W., Jr.; Melius, Carl F.; Allendorf, Mark D.; Arnold, James (Technical Monitor)

1998-01-01

The G2 atomization energies of fluorine and oxygen containing Ga compounds are greatly in error. This arises from an inversion of the Ga 3d core orbital and the F 2s or O 2s valence orbitals. Adding the Ga 3d orbital to the correlation treatment or removing the F 2s orbitals from the correlation treatment are shown to eliminate the problem. Removing the O 2s orbital from the correlation treatment reduces the error, but it can still be more than 6 kcal/mol. It is concluded that the experimental atomization energy of GaF2 is too large.

An Ultrahydrophobic Fluorous Metal-Organic Framework Derived Recyclable Composite as a Promising Platform to Tackle Marine Oil Spills.

PubMed

Mukherjee, Soumya; Kansara, Ankit M; Saha, Debasis; Gonnade, Rajesh; Mullangi, Dinesh; Manna, Biplab; Desai, Aamod V; Thorat, Shridhar H; Singh, Puyam S; Mukherjee, Arnab; Ghosh, Sujit K

2016-07-25

Derived from a strategically chosen hexafluorinated dicarboxylate linker aimed at the designed synthesis of a superhydrophobic metal-organic framework (MOF), the fluorine-rich nanospace of a water-stable MOF (UHMOF-100) exhibits excellent water-repellent features. It registered the highest water contact angle (≈176°) in the MOF domain, marking the first example of an ultrahydrophobic MOF. Various experimental and theoretical studies reinforce its distinctive water-repellent characteristics, and the conjugation of superoleophilicity and unparalleled hydrophobicity of a MOF material has been coherently exploited to achieve real-time oil/water separation in recyclable membrane form, with significant absorption capacity performance. This is also the first report of an oil/water separating fluorinated ultrahydrophobic MOF-based membrane material, with potential promise for tackling marine oil spillages. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantification of the fluorine containing drug 5-fluorouracil in cancer cells by GaF molecular absorption via high-resolution continuum source molecular absorption spectrometry

NASA Astrophysics Data System (ADS)

Krüger, Magnus; Huang, Mao-Dong; Becker-Roß, Helmut; Florek, Stefan; Ott, Ingo; Gust, Ronald

The development of high-resolution continuum source molecular absorption spectrometry made the quantification of fluorine feasible by measuring the molecular absorption as gallium monofluoride (GaF). Using this new technique, we developed on the example of 5-fluorouracil (5-FU) a graphite furnace method to quantify fluorine in organic molecules. The effect of 5-FU on the generation of the diatomic GaF molecule was investigated. The experimental conditions such as gallium nitrate amount, temperature program, interfering anions (represented as corresponding acids) and calibration for the determination of 5-FU in standard solution and in cellular matrix samples were investigated and optimized. The sample matrix showed no effect on the sensitivity of GaF molecular absorption. A simple calibration curve using an inorganic sodium fluoride solution can conveniently be used for the calibration. The described method is sensitive and the achievable limit of detection is 0.23 ng of 5-FU. In order to establish the concept of "fluorine as a probe in medicinal chemistry" an exemplary application was selected, in which the developed method was successfully demonstrated by performing cellular uptake studies of the 5-FU in human colon carcinoma cells.

Gold nanoparticles protected by mixed hydrogenated/fluorinated monolayers: controlling and exploring the surface features

NASA Astrophysics Data System (ADS)

Şologan, Maria; Gentilini, Cristina; Bidoggia, Silvia; Boccalon, Mariangela; Pace, Alice; Pengo, Paolo; Pasquato, Lucia

2018-06-01

Harnessing the reciprocal phobicity of hydrogenated and fluorinated thiolates proved to be a valuable strategy in preparing gold nanoparticles displaying mixed monolayers with a well-defined and pre-determined morphology. Our studies display that the organisation of the fluorinated ligands in phase-separated domains takes place even when these represent a small fraction of the ligands grafted on the gold surface. Using simple model ligands and by combining 19F NMR or ESR spectroscopies, and multiscale molecular simulations, we could demonstrate how the monolayer morphology responds in a predictable manner to structural differences between the thiolates. This enables a straightforward preparation of gold nanoparticles with monolayers displaying stripe-like, Janus, patchy, and random morphologies. Additionally, solubility properties may be tuned as function of the nature of the ligands and of the monolayer morphology obtaining gold nanoparticles soluble in organic solvents or in aqueous solutions. Most importantly, this rich diversity can be achieved not by resorting to ad hoc developed fabrication techniques, but rather relying on the spontaneous self-sorting of the ligands upon assembly on the nanoparticle surface. Besides enabling control over the monolayer morphology, fluorinated ligands endow the nanoparticles with several properties that can be exploited in the development of novel materials with applications, for instance in drug delivery and diagnostic imaging.

Surfaces of Fluorinated Pyridinium Block Copolymers with Enhanced Antibacterial Activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krishnan,S.; Ward, R.; Hexemer, A.

2006-01-01

Polystyrene-b-poly(4-vinylpyridine) copolymers were quaternized with 1-bromohexane and 6-perfluorooctyl-1-bromohexane. Surfaces prepared from these polymers were characterized by contact angle measurements, near-edge X-ray absorption fine structure spectroscopy and X-ray photoelectron spectroscopy. The fluorinated pyridinium surfaces showed enhanced antibacterial activity compared to their nonfluorinated counterparts. Even a polymer with a relatively low molecular weight pyridinium block showed high antimicrobial activity. The bactericidal effect was found to be related to the molecular composition and organization in the top 2-3 nm of the surface and increased with increasing hydrophilicity and pyridinium concentration of the surface.

Data-mining for sulfur and fluorine: an evaluation of pharmaceuticals to reveal opportunities for drug design and discovery.

PubMed

Ilardi, Elizabeth A; Vitaku, Edon; Njardarson, Jon T

2014-04-10

Among carbon, hydrogen, oxygen, and nitrogen, sulfur and fluorine are both leading constituents of the pharmaceuticals that comprise our medicinal history. In efforts to stimulate the minds of both the general public and expert scientist, statistics were collected from the trends associated with therapeutics spanning 12 disease categories (a total of 1969 drugs) from our new graphical montage compilation: disease focused pharmaceuticals posters. Each poster is a vibrant display of a collection of pharmaceuticals (including structural image, Food and Drug Administration (FDA) approval date, international nonproprietary name (INN), initial market name, and a color-coded subclass of function) organized chronologically and classified according to an association with a particular clinical indication. Specifically, the evolution and structural diversity of sulfur and the popular integration of fluorine into drugs introduced over the past 50 years are evaluated. The presented qualitative conclusions in this article aim to promote innovative insights into drug development.

Influence of Nanosegregation on the Surface Tension of Fluorinated Ionic Liquids

PubMed Central

Luís, Andreia; Shimizu, Karina; Araújo, João M. M.; Carvalho, Pedro J.; Lopes-da-Silva, José A.; Canongia Lopes, José N.; Rebelo, Luís Paulo N.; Coutinho, João A. P.; Freire, Mara G.; Pereiro, Ana B.

2017-01-01

We have investigated, both theoretically and experimentally, the balance between the presence of alkyl and perfluoroalkyl side chains on the surface organization and surface tension of fluorinated ionic liquids (FILs). A series of ILs composed of 1-alkyl-3-methylimidazolium cations ([CnC1im] with n = 2, 4, 6, 8, 10 or 12) combined with the perfluorobutanesulfonate anion was used. The surface tensions of the investigated liquid salts are considerably lower than those reported for non-fluorinated ionic liquids. The most surprising and striking feature was the identification, for the first time, of a minimum at n = 8 in the surface tension versus the length of the IL cation alkyl side chain. Supported by molecular dynamic simulations it was found that this trend is a result of the competition between the two nonpolar domains (perfluorinated and aliphatic) on pointing towards the gas-liquid interface, a phenomenon which occurs in ionic liquids with perfluorinated anions. Furthermore, these ionic liquids present the lowest surface entropy reported to date. PMID:27218210

Perfluoroalkyl acids: recent research highlights | Science ...

EPA Pesticide Factsheets

Perfluorinated compounds are organic chemicals in which all hydrogen molecules of the carbon-chain are substituted by fluorine molecules. Generally, there are two types of perfluorinated compounds, the perfluoroalkanes that are primarily used clinically for oxygenation and respiratory ventilation, and the perfluoroalkyl acids (PFAAs). Environmentally relevant PFAAs are a family of about 30 chemicals that consist of a carbon backbone typically 4-14 molecules in length and a charged functional group composed of either sulfonates, carboxylates or phosphonates (and to a lesser extent, phosphinates). While many (>100) derivatives ofPFAAs (such as alcohols, amides, esters and acids) are used for industrial and consumer applications, they can be degraded or metabolized to PFAAs as end-stage products. Thus, PFAAs, rather than their intermediates or derivatives, have drawn the most public attention and research interest. The most widely known PFAAs are the eight-carbon (C8) sulfonate (perfluorooctane sulfonate, PFOS) and carboxylate (perfluorooctanoic acid, PFOA), although the C4 (perfluorobutane) and C6 (perfluorohexane) sulfonates, as well as the C4, C6 and C9 (perfluorononanoic) carboxylates have also been used in commerce. The perfluoroalkyl phosphonates (PFPAs) are fairly new entities for this class ofchemicals. They are typically used as leveling and wetting agents, and defoaming additives in the production of pesticides. They were considered biologically inert by

Sources of halogens in the environment, influences on human and animal health.

PubMed

Fuge, R

1988-06-01

Of the halogens, fluorine has the highest crustal abundance (544 mg/kg) while iodine has the lowest (0.25 mg/kg), however, chlorine is by far the most abundant halogen in the cosmos. The geochemistries of the four naturally occurring halogens have some similarities with fluorine, chlorine and bromine being classified as lithophile elements while iodine is more chalcophile in nature. Bromine and iodine behave in a similar fashion in the secondary environment and could be classified as biophile elements being concentrated in organic matter. Chlorine, bromine and iodine are strongly enriched in the sea while iodine and to a lesser extent bromine are further concentrated in the marine algae.Apart from the occurrence of fluorine in fluorite (CaF2) there are few commonly occurring minerals which contain the halogens as essential constituents. In the igneous environment fluorine and chlorine tend to occupy hydroxyl lattice sites in micas, amphiboles, apatites etc., while in sediments clays can contain appreciable quantities of these elements. Bromine and iodine, however, would be unlikely to fit into the lattice sites of common rock-forming minerals.Bromine, like iodine, is probably volatilised from the marine environment and is carried on to land surfaces. This behaviour of iodine and bromine is reflected in the increased I/CI and Br/CI ratios of surface run-off in continental compared with near coastal environments.Limited information on the soil geochemistry of the halogens suggests that the soil contents of chlorine, bromine and iodine are influenced by proximity to the sea. Soil fluorine, however, is generally dependent on its content in the parent material. In some areas pollutant sources of the halogens contribute appreciably to their concentration in the environment.Iodine and chlorine are essential elements for mammals and fluorine has been shown to have beneficial effects on bone and tooth formation. However, excess quantities of dietary fluorine can be harmful. It is possible, in view of its ubiquitous occurrence in the biosphere, that bromine has a hitherto unknown function in human and animal health.

Synthesis, quantitative structure-property relationship study of novel fluorescence active 2-pyrazolines and application.

PubMed

Girgis, Adel S; Basta, Altaf H; El-Saied, Houssni; Mohamed, Mohamed A; Bedair, Ahmad H; Salim, Ahmad S

2018-03-01

A variety of fluorescence-active fluorinated pyrazolines 13-33 was synthesized in good yields through cyclocondensation reaction of propenones 1-9 with aryl hydrazines 10-12 . Some of the synthesized compounds provided promising fluorescence properties with quantum yield ( Φ ) higher than that of quinine sulfate (standard reference). Quantitative structure-property relationship studies were undertaken supporting the exhibited fluorescence properties and estimating the parameters governing properties. Five synthesized fluorescence-active pyrazolines ( 13 , 15 , 18 , 19 and 23 ) with variable Φ were selected for treating two types of paper sheets (Fabriano and Bible paper). These investigated fluorescence compounds, especially compounds 19 and 23 , provide improvements in strength properties of paper sheets. Based on the observed performance they can be used as markers in security documents.

Synthesis, quantitative structure–property relationship study of novel fluorescence active 2-pyrazolines and application

PubMed Central

Girgis, Adel S.; El-Saied, Houssni; Mohamed, Mohamed A.; Bedair, Ahmad H.; Salim, Ahmad S.

2018-01-01

A variety of fluorescence-active fluorinated pyrazolines 13–33 was synthesized in good yields through cyclocondensation reaction of propenones 1–9 with aryl hydrazines 10–12. Some of the synthesized compounds provided promising fluorescence properties with quantum yield (Φ) higher than that of quinine sulfate (standard reference). Quantitative structure–property relationship studies were undertaken supporting the exhibited fluorescence properties and estimating the parameters governing properties. Five synthesized fluorescence-active pyrazolines (13, 15, 18, 19 and 23) with variable Φ were selected for treating two types of paper sheets (Fabriano and Bible paper). These investigated fluorescence compounds, especially compounds 19 and 23, provide improvements in strength properties of paper sheets. Based on the observed performance they can be used as markers in security documents. PMID:29657796

Synthesis, quantitative structure-property relationship study of novel fluorescence active 2-pyrazolines and application

NASA Astrophysics Data System (ADS)

Girgis, Adel S.; Basta, Altaf H.; El-Saied, Houssni; Mohamed, Mohamed A.; Bedair, Ahmad H.; Salim, Ahmad S.

2018-03-01

A variety of fluorescence-active fluorinated pyrazolines 13-33 was synthesized in good yields through cyclocondensation reaction of propenones 1-9 with aryl hydrazines 10-12. Some of the synthesized compounds provided promising fluorescence properties with quantum yield (Φ) higher than that of quinine sulfate (standard reference). Quantitative structure-property relationship studies were undertaken supporting the exhibited fluorescence properties and estimating the parameters governing properties. Five synthesized fluorescence-active pyrazolines (13, 15, 18, 19 and 23) with variable Φ were selected for treating two types of paper sheets (Fabriano and Bible paper). These investigated fluorescence compounds, especially compounds 19 and 23, provide improvements in strength properties of paper sheets. Based on the observed performance they can be used as markers in security documents.

Induction slag reduction process for purifying metals

DOEpatents

Traut, Davis E.; Fisher, II, George T.; Hansen, Dennis A.

1991-01-01

A continuous method is provided for purifying and recovering transition metals such as neodymium and zirconium that become reactive at temperatures above about 500.degree. C. that comprises the steps of contacting the metal ore with an appropriate fluorinating agent such as an alkaline earth metal fluosilicate to form a fluometallic compound, and reducing the fluometallic compound with a suitable alkaline earth or alkali metal compound under molten conditions, such as provided in an induction slag metal furnace. The method of the invention is advantageous in that it is simpler and less expensive than methods used previously to recover pure metals, and it may be employed with a wide range of transition metals that were reactive with enclosures used in the prior art methods and were hard to obtain in uncontaminated form.

Space charge characteristics of fluorinated polyethylene: Different effects of fluorine and oxygen

NASA Astrophysics Data System (ADS)

Zhao, Ni; Nie, Yongjie; Li, Shengtao

2018-04-01

Direct fluorination are proved having obvious effect on space charge characteristics of polyethylene. It is believed that fluorine has a positive effect on suppressing space charge injection while oxygen impurity has a negative effect. However, the mechanism for the opposite effect of fluorine and oxygen is still not clear. In this paper, the different effects of fluorine and oxygen on space charge characteristics of fluorinated low density polyethylene (LDPE) are investigated on the basis of dielectric property, chemical constitutes and trap performance of surface fluorinated layers. The results show that direct fluorination has obvious effect on chemical constitutes and dielectric properties of surface fluorinated layer. Introduced fluorine is the main factor for suppressing charge injection from the electrodes, because it seriously changes the chemical constitutes and further the trap properties of the surface fluorinated layer. While introduction of oxygen results in heterocharges and makes space charge distribution complex, due to the ionization of generated small groups like C=O containing groups. Moreover, direct fluorination will result in cleavage of some LDPE molecules whatever there is oxygen impurity or not.

Identifying anthropogenic uranium compounds using soft X-ray near-edge absorption spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ward, Jesse D.; Bowden, Mark; Tom Resch, C.

2017-01-01

Uranium ores mined for industrial use are typically acid-leached to produce yellowcake and then converted into uranium halides for enrichment and purification. These anthropogenic chemical forms of uranium are distinct from their mineral counterparts. The purpose of this study is to use soft X-ray absorption spectroscopy to characterize several common anthropogenic uranium compounds important to the nuclear fuel cycle. Non-destructive chemical analyses of these compounds is important for process and environmental monitoring and X-ray absorption techniques have several advantages in this regard, including element-specificity, chemical sensitivity, and high spectral resolution. Oxygen K-edge spectra were collected for uranyl nitrate, uranyl fluoride,more » and uranyl chloride, and fluorine K-edge spectra were collected for uranyl fluoride and uranium tetrafluoride. Interpretation of the data is aided by comparisons to calculated spectra. These compounds have unique spectral signatures that can be used to identify unknown samples.« less

Reactivity of molecular dioxygen towards a series of isostructural dichloroiron(III) complexes with tripodal tetraamine ligands: general access to mu-oxodiiron(III) complexes and effect of alpha-fluorination on the reaction kinetics.

PubMed

Thallaj, Nasser K; Rotthaus, Olaf; Benhamou, Leila; Humbert, Nicolas; Elhabiri, Mourad; Lachkar, Mohammed; Welter, Richard; Albrecht-Gary, Anne-Marie; Mandon, Dominique

2008-01-01

We have synthesized the mono, di-, and tri-alpha-fluoro ligands in the tris(2-pyridylmethyl)amine (TPA) series, namely, FTPA, F(2)TPA and F(3)TPA, respectively. Fluorination at the alpha-position of these nitrogen-containing tripods shifts the oxidation potential of the ligand by 45-70 mV per added fluorine atom. The crystal structures of the dichloroiron(II) complexes with FTPA and F(2)TPA reveal that the iron center lies in a distorted octahedral geometry comparable to that already found in TPAFeCl(2). All spectroscopic data indicate that the geometry is retained in solution. These three isostructural complexes all react with molecular dioxygen to yield stable mu-oxodiiron(III) complexes. Crystal structure analyses are reported for each of these three mu-oxo compounds. With TPA, a symmetrical structure is obtained for a dicationic compound with the tripod coordinated in the kappa(4)N coordination mode. With FTPA, the compound is a neutral mu-oxodiiron(III) complex with a kappa(3)N coordination mode of the ligand. Oxygenation of the F(2)TPA complex gave a neutral unsymmetrical compound, the structure of which is reminiscent of that already found with the trifluorinated ligand. On reduction, all mu-oxodiiron(III) complexes revert to the starting iron(II) species. The oxygenation reaction parallels the well-known formation of mu-oxo derivatives from dioxygen in the chemistry of porphyrins reported almost three decades ago. The striking feature of the series of iron(II) precursors is the effect of the ligand on the kinetics of oxygenation of the complexes. Whereas the parent complex undergoes 90 % conversion over 40 h, the monofluorinated ligand provides a complex that has fully reacted after 30 h, whereas the reaction time for the complex with the difluorinated ligand is only 10 h. Analysis of the spectroscopic data reveals that formation of the mu-oxo complexes proceeds in two distinct reversible kinetic steps with k(1) approximately 10 k(2). For TPAFeCl(2) and FTPAFeCl(2) only small variations in the k(1) and k(2) values are observed. By contrast, F(2)TPAFeCl(2) exhibits k(1) and k(2) values that are ten times higher. These differences in kinetics are interpreted in the light of structural and electronic effects, especially the Lewis acidity at the metal center. Our results suggest coordination of dioxygen as an initial step in the process leading to formation of mu-oxodiiron(III) compounds, by contrast with an unlikely outer-sphere reduction of dioxygen, which generally occurs at negative potentials.

Copper-free Sonogashira cross-coupling for functionalization of alkyne-encoded proteins in aqueous medium and in bacterial cells.

PubMed

Li, Nan; Lim, Reyna K V; Edwardraja, Selvakumar; Lin, Qing

2011-10-05

Bioorthogonal reactions suitable for functionalization of genetically or metabolically encoded alkynes, for example, copper-catalyzed azide-alkyne cycloaddition reaction ("click chemistry"), have provided chemical tools to study biomolecular dynamics and function in living systems. Despite its prominence in organic synthesis, copper-free Sonogashira cross-coupling reaction suitable for biological applications has not been reported. In this work, we report the discovery of a robust aminopyrimidine-palladium(II) complex for copper-free Sonogashira cross-coupling that enables selective functionalization of a homopropargylglycine (HPG)-encoded ubiquitin protein in aqueous medium. A wide range of aromatic groups including fluorophores and fluorinated aromatic compounds can be readily introduced into the HPG-containing ubiquitin under mild conditions with good to excellent yields. The suitability of this reaction for functionalization of HPG-encoded ubiquitin in Escherichia coli was also demonstrated. The high efficiency of this new catalytic system should greatly enhance the utility of Sonogashira cross-coupling in bioorthogonal chemistry.

Synthesis and spectroscopic characterization of fluorescent 4-aminoantipyrine analogues: Molecular docking and in vitro cytotoxicity studies

NASA Astrophysics Data System (ADS)

Premnath, D.; Mosae Selvakumar, P.; Ravichandiran, P.; Tamil Selvan, G.; Indiraleka, M.; Jannet Vennila, J.

2016-01-01

Two substituted aromatic carbonyl compounds (compounds 1 and 2) of 4-aminoantipyrine were synthesized by condensation of fluorine substituted benzoyl chlorides and 4-aminoantipyrine. The structures of synthesized derivatives were established on the basis of UV-Vis, IR, and Mass, 1H, 13C NMR and Fluorescence spectroscopy. Both compounds showed significant fluorescence emission and two broad emission bands were observed in the region at 340 nm and 450 nm on excitation at 280 nm. Theoretically to prove that the molecule has anticancer activity against cervical cancer cells, the compounds were analyzed for molecular docking interactions with HPV16-E7 target protein by Glide protocol. Furthermore, 4-aminoantipyrine derivatives were evaluated for their in vitro cytotoxic activity against human cervical cancer cells (SiHa) by MTT assay. Compound 1 showed two fold higher activity (IC50 = 0.912 μM) over compound 2, and its activity was similar to that of Pazopanib, suggesting that although the two compounds were chemically very similar the difference in substituent on the phenyl moiety caused changes in properties.

Waste Minimization in Circuit Board Manufacturing by PARMOD(TM) Technology

DTIC Science & Technology

1998-06-24

a foil package in air or in a plastic syringe. Thermogravimetric Analysis (TGA) Ink samples were evaluated using thermogravimetric analysis in...DTA Differential Thermal Analysis FEP Fluorinated Ethylene Propylene (Teflon®) FTIR Fourier Transform Infrared spectroscopy MOD Metallo-Organic...Decomposition ROM Reactive Organic Medium SEM Scanning Electron Microscopy TGA Thermal Gravimetry Analysis Torr Unit of pressure (one mm mercury

The unique role of halogen substituents in the design of modern agrochemicals.

PubMed

Jeschke, Peter

2010-01-01

The past 30 years have witnessed a period of significant expansion in the use of halogenated compounds in the field of agrochemical research and development. The introduction of halogens into active ingredients has become an important concept in the quest for a modern agrochemical with optimal efficacy, environmental safety, user friendliness and economic viability. Outstanding progress has been made, especially in synthetic methods for particular halogen-substituted key intermediates that were previously prohibitively expensive. Interestingly, there has been a rise in the number of commercial products containing 'mixed' halogens, e.g. one or more fluorine, chlorine, bromine or iodine atoms in addition to one or more further halogen atoms. Extrapolation of the current trend indicates that a definite growth is to be expected in fluorine-substituted agrochemicals throughout the twenty-first century. A number of these recently developed agrochemical candidates containing halogen substituents represent novel classes of chemical compounds with new modes of action. However, the complex structure-activity relationships associated with biologically active molecules mean that the introduction of halogens can lead to either an increase or a decrease in the efficacy of a compound, depending on its changed mode of action, physicochemical properties, target interaction or metabolic susceptibility and transformation. In spite of modern design concepts, it is still difficult to predict the sites in a molecule at which halogen substitution will result in optimal desired effects. This review describes comprehensively the successful utilisation of halogens and their unique role in the design of modern agrochemicals, exemplified by various commercial products from Bayer CropScience coming from different agrochemical areas.

Coordination of XeF2 to calcium and cadmium hexafluorophosphates(V).

PubMed

Bunic, Tina; Tavcar, Gasper; Tramsek, Melita; Zemva, Boris

2006-02-06

[M(XeF2)5](PF6)2 (M = Ca, Cd) complexes were prepared by the reaction of MF2 and XeF2 under pressure of gaseous PF5 in anhydrous HF as solvent. The coordination sphere of the Ca atom consists of nine fluorine atoms: three from two PF6(-) units (one bidentate and one monodentate) and one from each of six XeF2 molecules. The coordination sphere of the Cd atom consists of eight fluorine atoms: one from each of two PF6(-) units and one from each of six XeF2 molecules. Two of the XeF2 ligands about M in each compound are bridging ligands and are each linked to two M, generating infinite (-M-F-Xe-F-M-F-Xe-F-) chains along the b-axis in the Ca salt and along the c-axis in the Cd compound. The Cd2+ cation is smaller and more electronegative than the Ca2+ cation. These differences account for the higher F ligand coordination in the Ca2+ salt and for other structural features that distinguish them. The different stoichiometry of the PF6(-) salts when compared with their AsF6(-) analogues, which have the composition [M(XeF2)4](AsF6)2 (M = Ca, Cd), is in accord with the lower F ligand charge in the AsF6(-) when compared with that in the PF6(-) compound. Indeed, the AsF6(-) ligand charges appear to be similar to those in the XeF2-bridged species.

Microbial toxicity and biodegradability of perfluorooctane sulfonate (PFOS) and shorter chain perfluoroalkyl and polyfluoroalkyl substances (PFASs).

PubMed

Ochoa-Herrera, Valeria; Field, Jim A; Luna-Velasco, Antonia; Sierra-Alvarez, Reyes

2016-09-14

Perfluorooctane sulfonate (PFOS) and related perfluoroalkyl and polyfluoroalkyl substances (PFASs) are emerging contaminants that have been widely applied in consumer and industrial applications for decades. However, PFOS has raised public concern due to its high bioaccumulative character, environmental persistence, and toxicity. Shorter PFASs such as perfluorobutane sulfonate (PFBS) and polyfluoroalkyl compounds have been proposed as alternatives to PFOS but it is unclear whether these fluorinated substances pose a risk for public health and the environment. The objective of this research was to investigate the microbial toxicity and the susceptibility to microbial degradation of PFOS and several related fluorinated compounds, i.e., short-chain perfluoroalkyl and polyfluoroalkyl sulfonic and carboxylic acids. None of the compounds tested were toxic to the methanogenic activity of anaerobic wastewater sludge even at very high concentrations (up to 500 mg L -1 ). All PFASs evaluated were highly resistant to microbial degradation. PFOS was not reductively dehalogenated by the anaerobic microbial consortium even after very long periods of incubation (3.4 years). Similarly, the tested short chain perfluoroalkyl substances (i.e., PFBS and trifluoroacetic acid) and a polyfluoroalkyl PFOS analogue, 6 : 2 fluorotelomer sulfonic acid (FTSA) were also resistant to anaerobic biodegradation. Likewise, no conclusive evidence of microbial degradation was observed under aerobic conditions for any of the short-chain perfluoroalkyl and polyfluoroalkyl carboxylic acids tested after 32 weeks of incubation. Collectively, these results indicate that PFOS and its alternatives such as short chain perfluoroalkyl sulfonates and carboxylates and their polyfluorinated homologues are highly resistant to microbial degradation.

Fluorine-fixing efficiency on calcium-based briquette: pilot experiment, demonstration and promotion.

PubMed

Yang, Jiao-lan; Chen, Dong-qing; Li, Shu-min; Yue, Yin-ling; Jin, Xin; Zhao, Bing-cheng; Ying, Bo

2010-02-05

The fluorosis derived from coal burning is a very serious problem in China. By using fluorine-fixing technology during coal burning we are able to reduce the release of fluorides in coal at the source in order to reduce pollution to the surrounding environment by coal burning pollutants as well as decrease the intake and accumulating amounts of fluorine in the human body. The aim of this study was to conduct a pilot experiment on calcium-based fluorine-fixing material efficiency during coal burning to demonstrate and promote the technology based on laboratory research. A proper amount of calcium-based fluorine sorbent was added into high-fluorine coal to form briquettes so that the fluorine in high-fluorine coal can be fixed in coal slag and its release into atmosphere reduced. We determined figures on various components in briquettes and fluorine in coal slag as well as the concentrations of indoor air pollutants, including fluoride, sulfur dioxide and respirable particulate matter (RPM), and evaluated the fluorine-fixing efficiency of calcium-based fluorine sorbents and the levels of indoor air pollutants. Pilot experiments on fluorine-fixing efficiency during coal burning as well as its demonstration and promotion were carried out separately in Guiding and Longli Counties of Guizhou Province, two areas with coal burning fluorosis problems. If the calcium-based fluorine sorbent mixed coal was made into honeycomb briquettes the average fluorine-fixing ratio in the pilot experiment was 71.8%. If the burning calcium-based fluorine-fixing bitumite was made into a coalball, the average of fluorine-fixing ratio was 77.3%. The concentration of fluoride, sulfur dioxide and PM10 of indoor air were decreased significantly. There was a 10% increase in the cost of briquettes due to the addition of calcium-based fluorine sorbent. The preparation process of calcium-based fluorine-fixing briquette is simple yet highly flammable and it is applicable to regions with abundant bitumite coal. As a small scale application, villagers may make fluorine-fixing coalballs or briquettes by themselves, achieving the optimum fluorine-fixing efficiency and reducing indoor air pollutants providing environmental and social benefits.

Copper-catalyzed intermolecular and regioselective aminofluorination of styrenes: facile access to β-fluoro-N-protected phenethylamines.

PubMed

Saavedra-Olavarría, Jorge; Arteaga, Gean C; López, Jhon J; Pérez, Edwin G

2015-02-25

A copper-catalyzed regio- and intermolecular aminofluorination of styrenes has been developed. In this reaction Ph-I=N-Ts and Et3N·3HF act as nitrogen and fluorine sources, respectively. The obtained β-fluoro-N-Ts-phenethylamines can be N-alkylated with subsequent deprotection affording the corresponding β-fluoro-N-alkylated phenethylamines, which are interesting building blocks for compounds acting on neuronal targets.

Reclassification of Materials Listed as Transportation Health Hazards

DTIC Science & Technology

1972-08-01

f. Hyg., 7:233, 1887. 152.3 Prentiss, A. M., Chemicals in War, McGrall-Hill, N. Y., 1937. A-183 TOXICITY DATA SHEET COMPOUND: CHLORINE TRIFLUORIDE ...l%3 Chlorine Trifluoride to # 161 Diborane Highly Toxic Extrenmely Toxic 169 Fluorine 171 Hlydrazine. anhydrous Toxic- Highly Toxic. 1I 172...were run on mice and rats exposed to chlorine , anhy lrous ammonia and hydrogen sulfide. Results have been included and reflected in the

REFINING FLUORINATED COMPOUNDS

DOEpatents

Linch, A.L.

1963-01-01

This invention relates to the method of refining a liquid perfluorinated hydrocarbon oil containing fluorocarbons from 12 to 28 carbon atoms per molecule by distilling between 150 deg C and 300 deg C at 10 mm Hg absolute pressure. The perfluorinated oil is washed with a chlorinated lower aliphatic hydrocarbon, which mairtains a separate liquid phase when mixed with the oil. Impurities detrimental to the stability of the oil are extracted by the chlorinated lower aliphatic hydrocarbon. (AEC)

Improving Photoconductance of Fluorinated Donors with Fluorinated Acceptors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garner, Logan E.; Larson, Bryon; Oosterhout, Stefan

2016-11-21

This work investigates the influence of fluorination of both donor and acceptor materials on the generation of free charge carriers in small molecule donor/fullerene acceptor BHJ OPV active layers. A fluorinated and non-fluorinated small molecule analogue were synthesized and their optoelectronic properties characterized. The intrinsic photoconductance of blends of these small molecule donors was investigated using time-resolved microwave conductivity. Blends of the two donor molecules with a traditional non-fluorinated fullerene (PC70BM) as well as a fluorinated fullerene (C60(CF3)2-1) were investigated using 5% and 50% fullerene loading. We demonstrate for the first time that photoconductance in a 50:50 donor:acceptor BHJ blendmore » using a fluorinated fullerene can actually be improved relative to a traditional non-fluorinated fullerene by fluorinating the donor molecule as well.« less

Nonmetallic Material Compatibility with Liquid Fluorine

NASA Technical Reports Server (NTRS)

Price, Harold G , Jr; Douglass, Howard W

1957-01-01

Static tests were made on the compatibility of liquid fluorine with several nonmetallic materials at -3200 F and at pressures of 0 and 1500 pounds per square inch gage. The results are compared with those from previous work with gaseous fluorine at the same pressures, but at atmospheric temperature. In general, although environmental effects were not always consistent, reactivity was least with the low-temperature, low-pressure liquid fluorine. Reactivity was greatest with the warm, high-pressure gaseous fluorine. None of the liquids and greases tested was found to be entirely suitable for use in fluorine systems. Polytrifluorochloroethylene and N-43, the formula for which is (C4F9)3N, did not react with liquid fluorine at atmospheric pressure or 1500 pounds per square inch gage under static conditions, but they did react when injected into liquid fluorine at 1500 pounds per square inch gage; they also reacted with gaseous fluorine at 1500 pounds per square inch gage. While water did not react with liquid fluorine at 1500 pounds per square inch gage, it is known to react violently with fluorine under other conditions. The pipe-thread lubricant Q-Seal did not react with liquid fluorine, but did react with gaseous fluorine at 1500 pounds per square inch gage. Of the solids, ruby (Al2O3) and Teflon did not react under the test conditions. The results show that the compatibility of fluorine with nonmetals depends on the state of the fluorine and the system design.

Perfluoroalkyl acids : Recent activities and research progress

EPA Science Inventory

The perfluoroalkyl acids (PFAAs) are a family of man-made fluorinated organic chemicals consisting of a carbon backbone typically of four to fourteen in length and a charged functional moiety (primarily carboxylate, sulfonate or phosphonate). The two most widely known PFAAs are ...

DEVELOPMENTAL TOXICITY OF PFOS AND PFOA

EPA Science Inventory

Perfluoroalkyl acids (PFAA) are fully-fluorinated organic chemicals with a carbon backbone (typically varying from C-4 to C-14) and a functional group (usually carboxylic acid or sulfonic acid). These chemicals are man-made, exceptionally stable to metabolic and environmental de...

Synthesis and animal studies of L-para-(/sup 18/F)-fluorophenyl-alanine as probe for in vivo cerebral protein synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coenen, H.H.; Bodsch, W.; Takahashi, K.

For the quantitation of cerebral protein synthesis in man by dynamic PET studies, fluorine-18 analogues seem superior to carbon-11 labeled substrates with respect to half-life and interference of amino acid metabolism giving rise to reutilization. Therefore, para- and ortho- /sup 18/F- fluorophenylalanine were prepared to study its metabolism in neuronal tissue. A labeling method was developed using direct electrophilic fluorination with (/sup 18/F)-F/sub 2/. Reaction of fluorine with L-phenylalanine in CF/sub 3/CO/sub 2/H at O/sup 0/C yielded 12-15% of ortho- and 6-8% of para-/sup 18/F-flurorophenylalanine. Isolation of the isomers was achieved by means of repeated RP-HPLC. The specific activity wasmore » about 2 Ci/mmole at 100 min after EOB. Both compounds showed a pharmacokinetic behaviour in mice after i.v. injection typical for natural amino acids. The accumulation in mice brain tissue reaches a plateau value after 5 min with 1.7% of the injected dose/g for para (2.5% in gerbils) and 2% for ortho. In a pilot study, about 1 mCi of p-/sup 18/F-phenylalanine was coinjected with 0.3 mCi (100 Ci/mmole) /sup 3/H-phenylalanine into the femoral vein of halothane-anesthetized Mongolian gerbils. The distribution obtained autoradiographyically in 20 ..mu..m sections of the frozen brain of an animal after 45 min revealed a similar pattern for both compounds indicating protein synthesis. In a parallel study 3-/sup 14/C-para-fluorophenylalanine was used to determine the chemical form of radioactivity in brain by means of HPLC. After 45 minutes, 7% of total brain activity was found as free amino acid and 60% was incorporated into proteins.« less

K- and L-edge X-ray absorption spectrum calculations of closed-shell carbon, silicon, germanium, and sulfur compounds using damped four-component density functional response theory.

PubMed

Fransson, Thomas; Burdakova, Daria; Norman, Patrick

2016-05-21

X-ray absorption spectra of carbon, silicon, germanium, and sulfur compounds have been investigated by means of damped four-component density functional response theory. It is demonstrated that a reliable description of relativistic effects is obtained at both K- and L-edges. Notably, an excellent agreement with experimental results is obtained for L2,3-spectra-with spin-orbit effects well accounted for-also in cases when the experimental intensity ratio deviates from the statistical one of 2 : 1. The theoretical results are consistent with calculations using standard response theory as well as recently reported real-time propagation methods in time-dependent density functional theory, and the virtues of different approaches are discussed. As compared to silane and silicon tetrachloride, an anomalous error in the absolute energy is reported for the L2,3-spectrum of silicon tetrafluoride, amounting to an additional spectral shift of ∼1 eV. This anomaly is also observed for other exchange-correlation functionals, but it is seen neither at other silicon edges nor at the carbon K-edge of fluorine derivatives of ethene. Considering the series of molecules SiH4-XFX with X = 1, 2, 3, 4, a gradual divergence from interpolated experimental ionization potentials is observed at the level of Kohn-Sham density functional theory (DFT), and to a smaller extent with the use of Hartree-Fock. This anomalous error is thus attributed partly to difficulties in correctly emulating the electronic structure effects imposed by the very electronegative fluorines, and partly due to inconsistencies in the spurious electron self-repulsion in DFT. Substitution with one, or possibly two, fluorine atoms is estimated to yield small enough errors to allow for reliable interpretations and predictions of L2,3-spectra of more complex and extended silicon-based systems.

Electrolytes including fluorinated solvents for use in electrochemical cells

DOEpatents

Tikhonov, Konstantin; Yip, Ka Ki; Lin, Tzu-Yuan

2015-07-07

Provided are electrochemical cells and electrolytes used to build such cells. The electrolytes include ion-supplying salts and fluorinated solvents capable of maintaining single phase solutions with the salts at between about -30.degree. C. to about 80.degree. C. The fluorinated solvents, such as fluorinated carbonates, fluorinated esters, and fluorinated esters, are less flammable than their non-fluorinated counterparts and increase safety characteristics of cells containing these solvents. The amount of fluorinated solvents in electrolytes may be between about 30% and 80% by weight not accounting weight of the salts. Fluorinated salts, such as fluoroalkyl-substituted LiPF.sub.6, fluoroalkyl-substituted LiBF.sub.4 salts, linear and cyclic imide salts as well as methide salts including fluorinated alkyl groups, may be used due to their solubility in the fluorinated solvents. In some embodiments, the electrolyte may also include a flame retardant, such as a phosphazene or, more specifically, a cyclic phosphazene and/or one or more ionic liquids.

Soils as sinks or sources for diffuse pollution of the water cycle

NASA Astrophysics Data System (ADS)

Grathwohl, Peter

2010-05-01

Numerous chemical compounds have been released into the environment by human activities and can nowadays be found everywhere, i.e. in the compartments water, soil, and air, at the poles and in high mountains. Examples for a global distribution of toxic compounds are the persistent organic pollutants (PCB, dioxins, PAH, fluorinated surfactants and flame retardants, etc.: "the Stockholm dirty dozen") but also mercury and other metals. Many of these compounds reached a global distribution via the atmo¬sphere; others have been and are still directly applied to top soils at the large scale by agriculture or are released into groundwater at landfill sites or by discharge of treated or untreated waste waters. Sooner or later such compounds end up in the water cycle - often via an intermediate storage in soils. Pollutants in soils are leached by seepage waters, transferred to ground¬water, and transported to rivers via groundwater flow. Adsorbed compounds may be transported from soils into surface waters by erosion processes and will end up in the sediments. Diffuse pollution of the subsurface environment not only reflects the history of the economic development of the modern society but it is still ongoing - e.g. the number of organic pollutants released into the environment is increasing even though the con¬centrations may decrease compared to the past. Evidence shows that many compounds are persistent in the subsurface environment at large time scales (up to centuries). Thus polluted soils already are or may become a future source for pollution of adjacent compartments such as the atmosphere and groundwater. A profound understanding on how diffuse pollutants are stored and processed in the subsurface environment is crucial to assess their long term fate and transport at large scales. Thus integrated studies e.g. at the catchment scale and models are needed which couple not only the relevant compartments (soil - atmosphere - groundwater/surface waters) but also flow and reactive transport. Field observations must allow long-term monitoring (e.g. in hydrological observatories, TERENO etc.), new cross-compartment monitoring strategies need to be applied, and massive parallel numerical codes for prediction of reactive transport of potential water pollutants at catchment scale have to be developed. This is also a prerequisite to assess the impact of climate change as well as land use change on future surface and groundwater quality.

Comparative in vitro toxicity assessment of perfluorinated carboxylic acids.

PubMed

Mahapatra, Cecon T; Damayanti, Nur P; Guffey, Samuel C; Serafin, Jennifer S; Irudayaraj, Joseph; Sepúlveda, Maria S

2017-06-01

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are synthetic fluorinated compounds that are highly bioaccumulative and persistent organic pollutants. Perfluorooctanoic acid (PFOA), an eight-carbon chain perfluorinated carboxylic acid, was used heavily for the production of fluoropolymers, but concerns have led to its replacement by shorter carbon chain homologues such as perfluorohexanoic acid (PFHxA) and perfluorobutanoic acid (PFBA). However, limited toxicity data exist for these substitutes. We evaluated the toxicity of PFOA, PFHxA and PFBA on a zebrafish liver cell line and investigated the effects of exposure on cell metabolism. Gross toxicity after 96 h of exposure was highest for PFOA and PFO - , while PFHxA and PFBA exhibited lower toxicity. Although the structural similarity of these compounds to fatty acids suggests the possibility of interference with the transport and metabolism of lipids, we could not detect any differential expression of peroxisome proliferator-activated receptor (ppar-α, -β and -γ), fabp3 and crot genes after 96 h exposure to up to 10 ppm of the test compounds. However, we observed localized lipid droplet accumulation only in PFBA-exposed cells. To study the effects of these compounds on cell metabolism, we conducted fluorescence lifetime imaging microscopy using naturally fluorescent biomarkers, NADH and FAD. The fluorescence lifetimes of NADH and FAD and the bound/free ratio of each of these coenzymes decreased in a dose- and carbon length-dependent manner, suggesting disruption of cell metabolism. In sum, our study revealed that PFASs with shorter carbon chains are less toxic than PFOA, and that exposure to sublethal dosage of PFOA, PFHxA or PFBA affects cell metabolism. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Dental caries in fluorine exposure areas in China.

PubMed

Binbin, Wang; Baoshan, Zheng; Hongying, Wang; Yakun, Ping; Yuehua, Tao

2005-12-01

In this study, fluorine concentrations in drinking water and in urine of residents from a fluorine exposure area in China were tested. DMFT (average number of decayed, missing and filled teeth) of local residents in four age groups were also determined. The results of the study indicate that in fluorine exposure areas, there is a strictly positive correlation between fluorine content in urine and the fluorine content in drinking water. Effect of dental caries by high fluorine content drinking water is different for the different age groups. High fluorine content drinking water is more dangerous for 15-and 18-year-old groups than 5- and 12-year-old groups.

Fluorine, fluorite, and fluorspar in central Colorado

USGS Publications Warehouse

Wallace, Alan R.

2010-01-01

Fluorine (F) is a widespread element that was deposited in a variety of rocks, minerals, and geologic environments in central Colorado. It occurs as a trace element, as a major component of the mineral fluorite (CaFs), and as a major economic source of fluorine in fluorspar deposits, which are massive concentrations of fluorite. This study has compiled available geochemical analyses of rocks, both unmineralized and mineralized, to determine the distribution of fluorine in specific age-lithologic categories, ranging from 1.8-giga-annum (Ga) metamorphic rocks to modern soils, throughout central Colorado. It also draws upon field studies of fluorine-rich mineral deposits, including fluorspar deposits, to decipher the nearly two-billion-year-long geologic history of fluorine in the study area, with implications for mineral-resource evaluations and exploration. The resulting compilation provides an important inventory of the naturally occurring levels and sources of fluorine that ultimately weather, erode, and become part of surface waters that are used for domestic water supplies in densely populated areas along the Colorado Front Range. Most commonly, fluorine is a trace element in virtually all rocks in the region. In the 3,798 unmineralized rocks that were analyzed for fluorine in the study area, the average fluorine content was 1,550 parts per million (ppm). The median was 640 ppm, nearly identical to the average crustal abundance of 650 ppm, and some high-fluorine rocks in the Pikes Peak area skewed the average to a value much greater than the median. Most unmineralized age-lithologic rock suites, including Proterozoic metamorphic rocks, 1.7- and 1.4-Ga granitic batholiths, Cambrian igneous rocks, Phanerozoic sedimentary rocks, and Laramide and Tertiary igneous rocks, had median fluorine values of 400 to 740 ppm fluorine. In all suites, however, a small number of analyzed samples contained more than 1 percent (10,000 ppm) fluorine. The 1.1-Ga plutonic rocks related to the Pikes Peak batholith had a mean fluorine content of 1,700 ppm, and primary magmatic fluorite and fluorite-bearing pegmatites are common throughout that igneous mass. Fluorine was deposited in many types of economic mineral deposits in central Colorado, and it currently is a significant trace element in some thermal springs. In the fluorspar deposits, fluorine contents were as high as 37 percent. Some fluorine-rich porphyry systems, such as Jamestown, had fluorine values that ranged from 200 ppm to nearly 37 percent fluorine, and veins in other deposits contained hydrothermal fluorite, although it was not ubiquitous. For the 495 samples from non-fluorspar mining districts (and excluding Jamestown), however, the median fluorine content was 990 ppm. This is above the crustal average but still relatively modest compared to the fluorspar deposits, and it indicates that the majority of the mineralizing systems in central Colorado did not deposit large amounts of fluorine. Nevertheless, the fluorine- and fluorite-rich mineral deposits could be used as guides for the evaluation and discovery of related but concealed porphyry and epithermal base- and precious-metal deposits. The Cenozoic geologic history of central Colorado included multiple periods during which fluorine-bearing rocks and mineral deposits were exposed, weathered, and eroded. This protracted history has released fluorine into soils and regoliths, and modern rainfall and snowmelt interact with these substrates to add fluorine to the hydrosphere. This study did not evaluate the fluorine contents of water or make any predictions about what areas might be major sources for dissolved fluorine. However, the abundant data that are available on fluorine in surface water and ground water can be coupled with the results of this study to provide additional insight into natural sources of fluorine in domestic drinking water.

Polymer-Supported Reagents and [to the first power]H-[to the nineteenth power]F NMR Couplings: The Synthesis of 2-Fluoroacetophenone

ERIC Educational Resources Information Center

Pohl, Nicola; Schwarz, Kimberly

2008-01-01

We describe an experiment for the undergraduate organic laboratory curriculum in which 2-bromoacetophenone is converted to 2-fluoroacetophenone using a solid-phase nucleophilic fluorine source. The experiment introduces students to the utility of solid-phase reagents in organic synthesis, to NMR-active nuclei other than [to the first power]H…

Comparative pharmacokinetics of perfluorononanoic acid in rat and mouse

EPA Science Inventory

Perfluorononanoic acid (PFNA) is a fluorinated organic chemical found at low levels in the environment, but is detectable in humans and wildlife. The present study compared the pharmacokinetic properties of PFNA in two laboratory rodent species. Male and female Sprague-Dawley rat...

Comparative Pharmacokinetics of Perfluorononanoic acid in Rats and Mice

EPA Science Inventory

Perfluorononanoic acid (PFNA) is a fluorinated organic chemical found at low levels in the environment, but is detectable in humans and wildlife. This study compared the pharmacokinetic properties of PFNA in two laboratory rodent species. Male and female Sprague-Dawley rats (n ...

Structure-activity relationships among substituted N-benzoyl derivatives of phenylalanine and its analogs in a microbial antitumor prescreen I: Derivatives of o-fluoro-DL-phenylalanine.

PubMed

Otani, T T; Briley, M R

1982-02-01

Twelve derivatives of 0-fluoro-dl-phenylalanine containing fluorine, chlorine, methoxy, and nitro radicals in various positions of the aromatic ring of the benzoyl group were prepared and tested in a Lactobacillus casei system. It was found that most substitutions in the benzoyl phenyl ring resulted in a compound exhibiting greater growth-inhibiting activity than the nonsubstituted benzoyl-o-fluorophenylalanine. The greatest activity was observed in the ortho-substituted fluoro compound and the meta- and para-substituted chloro and nitro compounds. With the methoxy group, the position of substitution appeared unimportant, since all three methoxy isomers exhibited essentially equal inhibition. Nitro substitution in the ortho position had a protective effect in that the product was less active than the unsubstituted benzoyl-o-fluoro-dl-phenylalanine.