78186-23-9Relevant academic research and scientific papers
A classical but new kinetic equation for hydride transfer reactions
Zhu, Xiao-Qing,Deng, Fei-Huang,Yang, Jin-Dong,Li, Xiu-Tao,Chen, Qiang,Lei, Nan-Ping,Meng, Fan-Kun,Zhao, Xiao-Peng,Han, Su-Hui,Hao, Er-Jun,Mu, Yuan-Yuan
, p. 6071 - 6089 (2013/09/12)
A classical but new kinetic equation to estimate activation energies of various hydride transfer reactions was developed according to transition state theory using the Morse-type free energy curves of hydride donors to release a hydride anion and hydride acceptors to capture a hydride anion and by which the activation energies of 187 typical hydride self-exchange reactions and more than thirty thousand hydride cross transfer reactions in acetonitrile were safely estimated in this work. Since the development of the kinetic equation is only on the basis of the related chemical bond changes of the hydride transfer reactants, the kinetic equation should be also suitable for proton transfer reactions, hydrogen atom transfer reactions and all the other chemical reactions involved with breaking and formation of chemical bonds. One of the most important contributions of this work is to have achieved the perfect unity of the kinetic equation and thermodynamic equation for hydride transfer reactions. The Royal Society of Chemistry.
Kinetics of the Reduction of 3,4-Dihydroisoquinolinium Cations by 1,4-Dihydronicotinamides
Bunting, John W.,Chew, Vivian S. F.,Chu, Gary
, p. 2308 - 2312 (2007/10/02)
Pseudo-first-order rate constants for the reduction of 2-methyl-3,4-dihydroisoquinolinium cation (1) by 1-(X-benzyl)-1,4-dihydronicotinamides (3) display kinetic saturation at high concentrations of 1 (20percent CH3CN-80percent H2O, 25 deg C, ionic strength 1.0).Association constants for 1:1 complex formation are independent of X (1.4 +/- 0.2 M-1) and are most simply interpreted in terms of nonproductive complex formation.Pseudo-first-order rate constants for the reduction of 2-(Z-benzyl)-3,4-dihydroisoquinolinium cations (2) by 3 are linear for up to approximately 60 mM.Hammett correlations for the second-order rate constants for these reactions give ρx = -0.77 for the reduction of 2 (Z = 4-CN) by 3 and ρz = 0.83 for the reduction of 2 by 3 (X = H).Comparisons of ρx and ρz with equilibrium ρ values for closely related reactions indicate that the migrating hydrogen atom bears a charge of -0.33 and thus is clearly hydridic in character.These results are closely analogous to the conclusions of our earlier study of the 1,4-dihydronicotinamide reduction of 5-nitroisoquinolinium cations which have similar pKR+ values to those for 2.Thus similar reduction mechanisms apply to the reduction of aromatic and nonaromatic cations by 3. pKR+ values for pseudobase formation from 2 are correlated with a Hammett ρ = 1.72.The second-order rate constant for hydroxide ion attack on 2 (X = H) is fivefold larger than for the 2-benzyl-5-nitroisoquinolinium cation, although the second-order rate constant for reduction by 3 (X = H) is 23-fold greater for the latter cation than for 2 (X = H).This is interpreted in terms of a poorer "fit" between 2 and 3 in the transition state for the reduction, relative to the better "fit" between the planar 5-nitroisoquinolinium cations and 3.
