Ph, R′= H, Et, CO2Me, SnMe3 are described. The molybdenum complexes possess a semi-bridged carbonyl thus rendering the molecules chiral; their 13C NMR spectra show four carbonyl resonances and two cyclopentadienyl environments. The barrier to racemisation depends on the bulk of the substituents on the ring. In contrast, the NMR spectra of the tungsten analogues show only single carbonyl and cyclopentadienyl
一系列分子[Cp'M(CO)2 ] 2(RCCR')的合成,其中Cp'= C 5 Me 5,C 5 H 4 Me;M = Mo,W;描述了R = Ph,R′= H,Et,CO 2 Me,SnMe 3。
钼配合物具有半桥羰基,因此使分子具有手性。他们的13 C NMR光谱显示了四个羰基共振和两个
环戊二烯基环境。外消旋化的障碍取决于环上取代基的大部分。相反,
钨类似物的NMR光谱显示,即使在-90°C和9.4 T下,也仅显示单个羰基和
环戊二烯基环境。