Friesen Dawn M, Bowles Owen J, McDonald Robert, Rosenberg Lisa
Department of Chemistry, University of Victoria, P.O. Box 3065, Victoria, British Columbia, CanadaV8W 3V6.
Dalton Trans. 2006 Jun 14(22):2671-82. doi: 10.1039/b516127d. Epub 2006 Apr 6.
The synthesis and structural characterization of a series of tripodal tris(phosphine) ligands, containing SiMe2 elbow groups, is described. The significant steric congestion in these ligands, due to the silylmethyl substituents, is manifest both in the solid-state structures and in the solution NMR spectra of the free ligands. Variable temperature 1H{31P} NMR studies of one of the ligands, CH3C(SiMe2PEt2)3 (4b) gave an estimated barrier to rotation around the Si-Capical bonds of approximately 10.4 kcal mol(-1). Octahedral kappa2- and kappa3-molybdenum complexes of these ligands also demonstrate the impact of the additional bulk imparted by the SiMe2 substituents, and the high Lewis basicity of these phosphines, with subtle changes at the apical and phosphine substituents changing the overall coordination chemistry observed.
描述了一系列含有二甲基硅“肘部”基团的三脚架型三（膦）配体的合成及结构表征。由于硅甲基取代基的存在，这些配体中存在显著的空间拥挤，这在固态结构和游离配体的溶液核磁共振谱中均有体现。对其中一种配体CH3C(SiMe2PEt2)3（4b）进行变温1H{31P}核磁共振研究，得出围绕硅-顶端键旋转的估计势垒约为10.4千卡·摩尔-1。这些配体的八面体κ2-和κ3-钼配合物也证明了二甲基硅取代基所带来的额外空间位阻的影响，以及这些膦的高路易斯碱性，顶端和膦取代基的细微变化改变了所观察到的整体配位化学。
