Unequivocal evidence for restricted rotation about a metal-arene bond caused by the steric effects of proximal ethyl groups; Crystal structure of dicarbonyltriphenylphosphine-(η6-1,3,5-triethyl- 2,4,6-tris(trimethylsilylmethyl)benzene)molybdenum(0)
作者:John A. Chudek、Geoffrey Hunter、Regina Louise MacKay、Gerald Färber、Walter Weissensteiner
DOI:10.1016/0022-328x(89)80105-6
日期:1989.11
The crystal structure of dicarbonyltriphenylphosphine(η6-1,3,5-triethyl-2,4,6- tris(trimethylsilylmethyl)benzene)molybdenum(0), (4) shows that the complexed arene adopts a conformation in which the three trimethylsilylmethyl groups and one ethyl group are on the side of the benzene ring plane distal to the molybdenum while the other two ethyl groups are on the proximal side. Decoalescence phenomena
二羰基三苯基膦(η 6 -1,3,5-三乙基-2,4,6-三(三甲基甲硅烷基甲基)苯)钼(0),( 4 )的晶体结构表明,络合芳烃采用三个三甲基甲硅烷基甲基的构象基团和一个乙基位于苯环平面远离钼的一侧,而另外两个乙基位于近侧。在4的 75.47 MHz 13 C- 1 H NMR 谱中观察到脱聚现象,最值得注意的是,在 145 K 时两个羰基共振得到解析。脱聚现象归因于:(i)乙基旋转减慢; (ii) 减慢三苯基膦配体绕 Mo$z.sbnd;P 键的旋转; (iii)减慢芳烃-金属三足键的旋转。