نتایج جستجو برای: fluorine

تعداد نتایج: 7204  

Journal: :Angewandte Chemie 2013
Theresa Liang Constanze N Neumann Tobias Ritter

Over the past decade, the most significant, conceptual advances in the field of fluorination were enabled most prominently by organo- and transition-metal catalysis. The most challenging transformation remains the formation of the parent C-F bond, primarily as a consequence of the high hydration energy of fluoride, strong metal-fluorine bonds, and highly polarized bonds to fluorine. Most fluori...

Journal: :Epidemiology and Infection 1946

2010
David O'Hagan

It is a pleasure to be able to introduce this second Thematic Series on ‘organo-fluorine chemistry’ within the Beilstein Journal of Organic Chemistry. The series now embeds the subject firmly as a special interest area of the journal. The first series in 2008 presented contributions representing a wide range of organic fluorine chemistry [1-10] and this series continues that trend exploring the...

Journal: :Science 2009

2004
Anna Strunecká Jiří Patočka Paul Connett

Fluoride has long been known to influence the activity of various enzymes in vitro. Latterly it has been demonstrated that many effects primarily attributed to fluoride are caused by a synergistic action of fluoride plus aluminum. Fluorinated chemicals are of growing importance, with applications in medicine. Fluorine substitution has profound effects on the properties of organic compounds. The...

Journal: :Dalton transactions 2015
Elisa I Carrera Dwight S Seferos

We present the reactivity and photochemistry of 2,5-diphenyltellurophene. A change in oxidation state from Te(ii) to Te(iv) occurs by oxidative addition of bromine, chlorine, and fluorine from appropriate halogen sources. Photoreductive halogen elimination is demonstrated using optical absorption spectroscopy and NMR spectroscopy. The photodebromination reaction occurs with 16.9% quantum yield,...

2006
K. Szymańska F. Domka

The effect of soluble fluorine species in different concentrations on the catabolic activity of Desulfotomaculum ruminis bacteria has been studied. The fluoride concentrations tolerated by and toxic to the bacteria have been determined. The degree of fluorine species toxicity was found to depend on the form in which fluorine is introduced into the medium and increases in the following order: Na...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1976
K J Longmuir F W Dahlquist

Distearoylphosphatidylcholines labeled with gem-difluoro groups at selected positions of the fatty acid chains have been prepared. These lipids were incorporated into sonicated vesicles and were examined by fluorine nuclear magnetic resonance spectroscopy. All spectra are characterized by two well-separated fluorine resonances. Paramagnetic ions added to the exterior solution of vesicles of flu...

Journal: :Journal of the American Chemical Society 2011
Justin Wu Liming Xie Yanguang Li Hailiang Wang Yijian Ouyang Jing Guo Hongjie Dai

We investigated the chlorine plasma reaction with graphene and graphene nanoribbons and compared it with the hydrogen and fluorine plasma reactions. Unlike the rapid destruction of graphene by hydrogen and fluorine plasmas, much slower reaction kinetics between the chlorine plasma and graphene were observed, allowing for controlled chlorination. Electrical measurements on graphene sheets, graph...

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