نتایج جستجو برای: hammett constant

تعداد نتایج: 218513  

Journal: :Journal of chemical information and modeling 2007
Rafal Gieleciak Jaroslaw Polanski

A variety of issues decide the efficiency of 3D QSAR methods, and their practical importance for drug design is still controversial. This refers both to the predictive ability and the possibility for the indication of these areas within 3D molecular representations that are responsible for biological or chemical effects. Technically, the latter comes down to the selection or elimination of the ...

Journal: :Journal of Physical Organic Chemistry 2022

Three distinct procedures for obtaining the effective Gibbs energies of activation from computed a reaction involving multiple reactant-state (RS) and transition-state (TS) conformers are shown to be equivalent. If Boltzmann-weighted average RS TS evaluated, then energy contribution entropy mixing both must also included in order obtain correct value activation. Application solvolytic 4,4′-dime...

Journal: :Compounds 2023

The ability for density functional theory with the B3LYP lanl2dz basis set to predict 1st (Wave 1) and 2nd 2) reductions of diazine ring in a series thirty-seven (37) 1,4-di-N-oxide quinoxaline-2-carboxamide derivatives dimethylformamide was examined. B3LYP/lanl2dz method had strong correlation low experimental potentials Wave 1 2, respectively. There are nine identifiable analogs based on simi...

Journal: :Fórum de Literatura Brasileira Contemporânea 2022

Este ensaio busca analisar as masculinidades dos personagens detetivescos na ficção policial. Partindo do personagem Dupin, o detetive racional de Edgar Allan Poe, e passando por Philip Marlowe Sam Spade, os detetives “durões” Raymond Chandler Dashiell Hammett, respectivamente, pretendo me ater ao Espinosa, Luiz Alfredo Garcia-Roza, selecionando para análise romance O silêncio da chuva. Alio-me...

Journal: :Dalton transactions 2011
Hitoshi Miyasaka Natsuko Motokawa Ryo Atsuumi Hiromichi Kamo Yuichiro Asai Masahiro Yamashita

A series of paddlewheel diruthenium(ii, ii) complexes with various fluorine-substituted benzoate ligands were isolated as THF adducts and structurally characterized: [Ru(2)(F(x)PhCO(2))(4)(THF)(2)] (F(x)PhCO(2)(-) = o-fluorobenzoate, o-F; m-fluorobenzoate, m-F; p-fluorobenzoate, p-F; 2,6-difluorobenzoate, 2,6-F(2); 3,4-difluorobenzoate, 3,4-F(2); 3,5-difluorobenzoate, 3,5-F(2); 2,3,4-trifluorob...

2009
Cédric KEPKA Maël PENHOAT Didier BARBRY

Evaluation of a new proton sponge, bis-1,1,8,8-(tetramethylguanidino)naphtalene (TMGN), in substituted phenols O-alkylation by methyl iodide in DMF has been studied. Kinetic measurements were performed in N,N-dimethylformamide-d7 and followed by H NMR using stoichiometric amounts of reagents. Plot of the results shows that the reaction follows an almost perfect second order rate law. However th...

Journal: :The Yale Journal of Biology and Medicine 1942
H. S. Burr

All mature living organisms possess relatively constant potential differences ibetween any two points. To some extent, at least, these standing potential differences are a measure of an electrical reservoir, which may be called upon by the various organ systems during activity. They can be measured at all times during life and disappear upon death. They are arranged in characteristic patterns a...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2004
Michael P Doyle Marcela Valenzuela Penglin Huang

Chiral dirhodium(II) carboxamidates are highly efficient catalysts for reactions between a variety of aldehydes and activated dienes. Catalyst loadings as low at 0.01 mol % have been realized with enantioselectivities up to 97%. Kinetic investigations reveal a pronounced electronic influence on the rate of the hetero-Diels-Alder reaction with a Hammett rho value of +1.9 (versus sigma(+)). Inhib...

Journal: :The Journal of organic chemistry 2001
Z Qu W Shi J Wang

The relative rate constants for the Rh(II)-mediated diazo decomposition of a series of para- or meta-substituted diazophenylacetates were measured through intermolecular competition. The kinetic data were further subjected to Hammett correlation analysis and were found to have better linear correlation with sigma(+). Reaction constants for four Rh(II) catalysts have been obtained, Rh(2)(OAc)(4)...

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