Photochemistry of some deoxybenzoins in micellar solutions. Cage effects, isotope effects, and magnetic field effects
作者:Nicholas J. Turro、Jochen Mattay
DOI:10.1021/ja00404a037
日期:1981.7
investigated. It was found that the extent of cage disproprotionation to yield benzaldehydes 6 and ..cap alpha..-methylstyrenes 7 is enhanced by a factor of about 10 compared to the photolyses in homogeneous organic solvents. The advantage of using micelles rather than homogeneous solutions to enhance the magnitude of magnetic isotope and magnetic field effects on cage disproportionation is demonstrated. The
The present invention relates to metal complexes and to electronic devices, in particular organic electroluminescent devices, comprising these metal complexes.
The present invention relates to metal complexes and to electronic devices, in particular organic electroluminescent devices, comprising these metal complexes.
本发明涉及金属络合物和包含这些金属络合物的电子器件,特别是有机电致发光器件。
Ion−Molecule Pairs in Leaving-Group-Promoted Solvolytic Elimination Reactions
作者:Alf Thibblin、Yoshihiro Saeki
DOI:10.1021/jo9619645
日期:1997.2.1
Solvolysis of 1-(1-methyl-1-phenylethyl)pyridinium cation (1-P+) in 25% vol acetonitrile in water at 60 degrees C provides the substitution product 2-hydroxy-2-phenylpropane (1-OH) and the elimination product 2-phenylpropene (3). The fraction of elimination is about half of that obtained with an acetate leaving group of similar basicity. The total rate of reaction is dependent on the basicity of the leaving group, 1-(1-methyl-1-(4-cyanophenyl)ethyl)pyridinium cation (1-P-CN+) reacts 1100 times faster than 1-P+ which corresponds to a Bronsted parameter of beta(lg) = -0.93. Also the fraction of elimination is leaving-group dependent as expressed by a Bronsted parameter of beta = 0.12 for the dehydronation of the ion-molecule pair by the leaving group. Addition of substituted pyridines has only a minor effect on the product ratio. The reactions are concluded to occur stepwise through a common carbocation intermediate of ion-molecule pair type. The overall kinetic deuterium isotope effects using the hexadeuteriated analogs were measured as k(obs)(H)/k(obs)(D6) = 1.85 +/- 0.10 (60 degrees C) with the pyridinium ion 1-P+ and as k(obs)(H)/k(obs)(D6) = 1.53 +/- 0.06 (40 degrees C) with the 4-cyanopyridinium ion 1-P-CN+. The kinetic deuterium isotope effects on the elimination step (assuming the reaction from intermediate to alcohol is insensitive to isotopic substitution) were measured as k(e)(H)/k(e)(D6) = 2.7 +/- 0.2 for 1-P+ (60 degrees C) and 3.4 +/- 0.2 for 1-P-CN+ (40 degrees C).