Highly Effective Pincer-Ligated Iridium Catalysts for Alkane Dehydrogenation. DFT Calculations of Relevant Thermodynamic, Kinetic, and Spectroscopic Properties
作者:Keming Zhu、Patrick D. Achord、Xiawei Zhang、Karsten Krogh-Jespersen、Alan S. Goldman
DOI:10.1021/ja047356l
日期:2004.10.1
in the same directions, relative to the parent PCP ligand, for the kinetics and thermodynamics of a broad range of reactions including the addition of C-H and H-H bonds and CO. In general, both ligands favor (relative to unsubstituted PCP) addition to the 14e (pincer)Ir fragments but disfavor addition to the 16e complexes (pincer)IrH(2) or (pincer)Ir(CO). These kinetic and thermodynamic effects are
p-甲氧基取代的钳形连接铱配合物,(MeO-(tBu)PCP)IrH(4) ((R)PCP = kappa(3)-C(6)H(3)-2,6-(CH (2)PR(2))(2)) 和 (MeO-(iPr)PCP)IrH(4) 被发现是烷烃脱氢的高效催化剂(使用和不使用牺牲氢受体) . 这些配合物与最近报道的双亚膦酸盐“POCOP”((R)POCOP = kappa(3)-C(6)H(3)-2,6-(OPR(2))(2))进行了有趣的比较钳连接催化剂,其催化活性也高于未取代的 PCP 类似物(Gottker-Schnetmann, I.;White, P.;Brookhart, MJ Am. Chem. Soc. 2004, 126, 1804)。根据各个 CO 加合物的 nu(CO) 值,MeO-PCP 复合物似乎比母体 PCP 复合物更富电子,而 POCOP 复合物似乎更缺乏电子。然而,计算