An Insight into the Reversible Dissociation and Chemical Reactivity of a Sterically Encumbered Diphosphane
作者:Daniela Förster、Herbert Dilger、Fabian Ehret、Martin Nieger、Dietrich Gudat
DOI:10.1002/ejic.201200633
日期:2012.9
Equilibrium constants for the dissociation 4a [rlarr2] 2 5a were determined from quantitative variable-temperature electron paramagnetic resonance(VT-EPR) studies and were used to obtain thermochemical data for the P–P bond homolysis. The calculated bond dissociation energy of 79(1) kJ mol–1 is substantially lower than the gas-phase dissociation energies of small diphosphanes. Modeling of the molecular
已知的 1,1',3,3'-四氢-2,2'-bi-1,3,2-二氮杂磷 4a 首次在制备规模上合成并通过光谱表征。解离 4a [rlarr2] 2 5a 的平衡常数由定量变温电子顺磁共振 (VT-EPR) 研究确定,并用于获得 P-P 键均裂的热化学数据。79(1) kJ mol-1 的计算键解离能大大低于小二膦的气相解离能。如果包括色散效应,通过 DFT 计算对 4a 的分子结构进行建模是可行的,但计算仍然未能合理解释解离过程的能量学。4a 与炔烃的化学反应进行,取决于底物结构,