Small Molecule Activation by 4-N,N-Dimethylaminopyridine-Stabilized Bis(silyl)germylenes

The synthesis, characterization, and reactivity of DMAP & sdot;Ge(SitBu3)Si(TMS)3 1 a and DMAP & sdot;Ge[Si(TMS)3]2 1 b are reported (DMAP = 4-N,N-Dimethylaminopyridine). These germylenes were isolated in moderate yields by the reaction of DMAP & sdot;GeCl2 with NaSitBu3 & sdot;(THF)2 and KSi(TMS)3 & sdot;(THF)1.2 or 2 equivalents of KSi(TMS)3 & sdot;(THF)1.2, respectively, at low temperature (TMS = Trimethylsilyl). Exposure of 1 a to dihydrogen forms the tetravalent germanium hydride species GeH2(SitBu3)Si(TMS)3 2 a. Additionally, the reactivity of 1 a,b towards the substitution of 2,6-dimethylphenyl isocyanide (CNXyl) 3 a,b, the alkyne cycloaddition of diphenylacetylene (PhCCPh) 4 a,b, and the substitution of DMAP for NHC using 1,3,4,5-tetramethylimidazol-2-ylidene (IMe4) 5 a,b was investigated (NHC = N-heterocyclic carbene). Reaction products were characterized by multinuclear magnetic resonance (NMR), infrared (IR) spectroscopy, mass spectrometric analysis, and single-crystal X-ray diffraction (SC-XRD) study.