Synthesis, Structure, and Reactions of a (η3-α-silabenzyl)molybdenum Complex: A Synthetic Equivalent of a Coordinatively Unsaturated Silyl Complex

Abstract

The (η3-α-silabenzyl)molybdenum complex Cp*Mo(CO)2{η3(Si,C,C)-Si(p-Tol)3} (1; Cp* = η5-C5Me5, p-Tol = p-C6H4Me) was synthesized in high yield by removal of 4-(dimethylamino)pyridine (DMAP) from the (arylsilyl)(DMAP)molybdenum complex Cp*Mo(CO)2(DMAP){Si(p-Tol)3} (2) with BPh3. The precursor, complex 2, was readily prepared by reaction of the (DMAP)(methyl)molybdenum complex Cp*Mo(CO)2(DMAP)Me (3) with tri-p-tolylsilane (HSi(p-Tol)3) through methane elimination. Study on the reactivity of 1 toward DMAP and nitrile revealed that complex 1 serves as a synthetic equivalent of the 16-electron silyl complex Cp*Mo(CO)2{Si(p-Tol)3}. Thus, complex 1 reacted with DMAP quantitatively at room temperature to reproduce arylsilyl complex 2 through dissociation of the arene carbon atoms coordinated to molybdenum. Complex 1 also reacted with acetonitrile at room temperature to give the N-silyliminoacyl complex Cp*Mo(CO)2{η2(C,N)-C(Me)═NSi(p-Tol)3} (4) exclusively via cleavage of the Mo–C(arene) bonds followed by insertion...