Hydrogen Bonding Lowers Intrinsic Nucleophilicity of Solvated Nucleophiles
作者:Xin Chen、John I. Brauman
DOI:10.1021/ja802814a
日期:2008.11.12
The relationship between nucleophilicity and the structure/environment of the nucleophile is of fundamental importance in organic chemistry. In this work, we have measured nucleophilicities of a series of substituted alkoxides in the gasphase. The functional group substitutions affect the nucleophiles through ion-dipole, ion-induced dipole interactions and through hydrogen bonding whenever structurally
亲核性与亲核试剂的结构/环境之间的关系在有机化学中至关重要。在这项工作中,我们测量了一系列取代醇盐在气相中的亲核性。官能团取代通过离子-偶极子、离子诱导偶极子相互作用和结构上可能的氢键影响亲核试剂。这组醇盐是在微溶剂化设置下研究亲核试剂的理想模型系统。应用马库斯理论来分析结果。使用 Marcus 理论,我们将亲核性分成两个独立的部分,即内在亲核性和仅由总反应放热性决定的热力学驱动力。发现取代醇盐的表观亲核性总是远低于未取代醇盐的亲核性。然而,离子-偶极子、离子诱导的偶极子相互作用本身不会显着影响固有的亲核性。表观亲核性的降低是由于较弱的热力学驱动力造成的。另一方面,氢键不仅可以稳定亲核试剂,还可以将本征势垒高度增加 3 至大约 4 kcal mol (-1)。在这方面,氢键不是作为外部偶极子意义上的扰动,而是更直接地影响亲核醇盐的电子结构和反应性。这一发现让我们更深入地了解溶剂化对亲核性的影响,
MOGER, G.;GYOR, M., TETRAHEDRON LETT., 30,(1989) N2, C. 7467-7468
作者:MOGER, G.、GYOR, M.
DOI:——
日期:——
Mechanistic studies on gas-phase negative ion unimolecular decompositions. Alkoxide anions
作者:William. Tumas、Robert F. Foster、John I. Brauman
DOI:10.1021/ja00217a003
日期:1988.4
Les ions alcoolates subissent une elimination de molecules neutres pour donner des ions enolates
Les ion alcoolates subissent une demoles neutres pour donner des ions enolates
Phototochemistry of cation radicals in solution; photoinduced electron-transfer reactions between alcholos and the N,N,N′,N′,-tetraphenyl-p-phenylenediamine cation radical
作者:Jean-Claude Moutet、Gilbert Reverdy
DOI:10.1039/c39820000654
日期:——
Irradiation of the N,N,N′,N′-tetraphenyl-p-phenylanediamine cationradical (TPPD·+) with benzyl alchohol causes its reduction to TPPD and oxidation of the alcohol into benzaldehyde; with benzhydrol and 1-phenylethanol the corresponding symmetrical ethers are formed in a photocatalytic process in which TPPD·+ is recycled via two successive electron transfers.