Results 141 to 150 of about 3,195 (187)

Selective Recognition of Alkyl Pyranosides in Protic and Aprotic Solvents

Journal of the American Chemical Society, 2008
The design and synthesis of receptors capable of selective, noncovalent recognition of carbohydrates continues to be a signature challenge in bioorganic chemistry. We report a new generation of tripodal receptors incorporating three pyridine (compound 2) or quinoline (compound 3) rings around a central cyclohexane core for use in molecular recognition ...
Prakash B, Palde, Peter C, Gareiss, Benjamin L, Miller   +2 more
openaire   +2 more sources

Photooxidation of Co-thiolato complexes in protic and aprotic solvents

Chemical Communications, 2006
Protic solvents decrease the susceptibility of the thiolate ligand in Co(III) thiolato complexes toward attack by singlet oxygen, but greatly increase the conversion of the peroxidic intermediate to the sulfenato product.
Billy, Hernandez, Yanju, Wang, Dong, Zhang, Matthias, Selke   +3 more
openaire   +2 more sources

New protic salts of aprotic polar solvents

Tetrahedron Letters, 2004
Abstract Aprotic polar solvents such as DMF, acetonitrile or DMSO can be protonated to form stable triflate salts when treated with triflic acid. The reaction of the same solvents with N , N -bis(trifluoromethanesulfonyl)imide led to the isolation of the corresponding N , N -bis(trifluoromethanesulfonyl)imide salts.
Isabelle Favier, Elisabet Duñach
openaire   +1 more source

Aminolysis of oxime ethers in protic and aprotic solvents

Journal of the Chemical Society, Perkin Transactions 2, 1989
Reactions of oxime ethers with the primary amines, n-propyl-, n-butyl-, n-pentyl-, and n-hexylamine in DMSO, DMF, and MeCN are strongly catalysed by general bases. The observed secondorder rate constants (kA) exhibit a curvilinear dependence on amine concentration leaving a positive intercept.
Ajay K. Jain, Anurag Kumar, Kula N. Sarma   +2 more
openaire   +1 more source

Solvation of acetone in protic and aprotic solvents and binary solvent mixtures

Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, 1985
The infrared spectra of dilute solutions of acetone in a range of protic and aprotic solvents have been measured in the C—O stretch region. Band maxima are shown to correlate linearly with 13C n.m.r. shifts for the carbonyl carbon and, after suitable corrections, with solvent acceptor numbers.
Martyn C. R. Symons, Graham Eaton
openaire   +1 more source

Isotropic magnetic shielding constants of retinal derivatives in aprotic and protic solvents

The Journal of Chemical Physics, 2013
We investigate the nuclear isotropic shielding constants σ(13C) and σ(17O) of isomers of retinoic acid and retinal in gas-phase and in chloroform, acetonitrile, methanol, and water solutions via Monte Carlo simulation and quantum mechanics calculations using the GIAO-B3LYP/6-311++G(2d,2p) approach.
G, Colherinhas, T L, Fonseca, M A, Castro, K, Coutinho, S, Canuto   +4 more
openaire   +2 more sources

DPPH assay of vegetable oils and model antioxidants in protic and aprotic solvents

Talanta, 2013
The rate of reaction of phenolic antioxidants with DPPH depends on solvent composition. The rate constants can differ by more than two orders of magnitude for the same phenolic compound. Reactions are faster in alcohols than in ethyl acetate that is used routinely for the analysis of antioxidant potential (AOP) of nonpolar samples such as vegetable ...
Tjaša, Prevc, Nataša, Segatin, Nataša Poklar, Ulrih, Blaž, Cigić   +3 more
openaire   +2 more sources

Solvent effect on nonradiative process of pyronin B in protic and aprotic solvent systems

Journal of Luminescence, 2002
Abstract Absorption and emission spectra of pyronin B were taken in acetonitrile and acetonitrile-benzene solvent mixtures. Fluorescence lifetime (τf) and quantum yield (Φf) were determined as a function of temperature and nonradiative rate constant (knr) was calculated from τf and Φf.
ARIK, M, ACEMIOGLU, B, Onganer, Yavuz
openaire   +2 more sources

Diffusion of symmetrical and spherical solutes in protic, aprotic, and hydrocarbon solvents

Journal of Solution Chemistry, 1979
The diffusion coefficients of a series of symmetrical tetraalkyltins (tetramethyltin, tetraethyltin, tetrapropyltin, tetrabutyltin, tetradodecyltin) of the gases argon, krypton, xenon, methane, and tetramethylmethane and of carbon tetrachloride and tetraethylmethane in hexane, decane, and tetradecane at 25°C have been determined using the Taylor ...
D. Fennell Evans, Toshihiro Tominaga, C. Chan   +2 more
openaire   +1 more source

Dipolar aprotic–protic solvent influences in the hydrolysis of diol monoesters

International Journal of Chemical Kinetics, 1974
AbstractThe kinetics of the alkaline hydrolysis of five diol monoesters and related esters in aqueous DMSO, aqueous acetone, and aqueous ethanol are reported. A novel solvent dependency of the reactivity pattern of the various esters is noticed.
M. Balakrishnan, G. Venkoba Rao, N. Venkatasubramanian   +2 more
openaire   +1 more source