The effect of replacing carbonyl with acetonitrile on the reactivity of the bimetallic system [Mo_2Cp_2(#mu#-SMe)_3(L)_2]~+ (L=CO, CH_3CN). Crystal structure of [Mo_2Cp_2(#mu#-SMe)_2(CH_3CN_4)](BE_4)_2

摘要

[Mo_2Cp_2(#mu#-SMe)_3(CH_3CN)_2](BF_4) (1) reacts with H[BF_4] in acetonitrile at room temperature to give the tetrakis (acetonitrile) compound [Mo_2Cp_2(#mu#-SMe)_2(CH_3CN)_4](BF_4)_2 (3) trough replacement of one SMe bridge by two terminal CH_3CN ligands. In sharp contrast, the carbonyl analogue [Mo_2Cp_2(#mu#-SMe)_3(CO)_2]~+ (2) fails to undergo a similar reaction. This suggests that the electronic properties of the ancillary ligands L in the [Mo_2Cp_2(#mu#-SMe)_3L_2]~+ moiety govern the activation of a sulfur atom in protonation reactions. An X-ray diffraction study shows that 3 contains two CpMo(CH_3CN)_2 units bridged by two SMe groups and linked by a long Mo-Mo bond of 3.000(1) A.