1,2-Dibenzyltetradimethylamido-Dimolybdenum and -Ditungsten (M=M) Compounds and Their Reactions with Carbon Dioxide and 1,3-Diaryltriazines. A Radical Difference

摘要

The preparation of 1,2-M2(benzyl) 2(NMe2)4 (M=M) compounds (M = Mo and W) and their reactions with each of CO2 and 1,3-diaryltriazines are described. The molybdenum and tungsten dibenzyl compounds differ in their reactivity quite markedly. For tungsten, the M=M bond is preserved in the formation of W2(benzyl)2-(NMe2)2(ArN3Ar)2 and W2(benzyl)2(O2CNMe2)4 compounds, while molybdenum favors reductive elimination and formation of M-M quadruply bonded compounds Mo2(O2CN-Me2)4 and Mo2(ArN3Ar)2, where Ar = phenyl and p-tolyl. Reductive elimination is shown to proceed via a radical pathway. (Author)