Synthesis and reactivity of (pentamethylcyclopentadienyl)ruthenium complexes of the stable neutral silylene Si(tBuNCH=CHNtBu)

The coordination chemistry of the stable silylene Si((BuNCHCHNBu)-Bu-t-Bu-t) (1) in Cp*Ru complexes has been investigated. Silylene 1 reacts with 0.25 equiv of [Cp*RuCl](4) to give the 16-electron Ru silylene complex Cp*{n(1)-Si((BuNCHCHNBu)-Bu-t-Bu-t)}RuCl (2). This complex reacts with primary silanes to give the unusual products [(Cp*Ru)(2)(H)(mu -H)(mu,eta (2)-HSiRCl)(mu,eta (2)-ClSi((t)- (BuNCHCHNBu)-Bu-t)] (3, R = Ph; 4, R = Hex (eta -hexyl)). The structures of these products were confirmed by H-1, C-13 and Si-29 NMR and IR spectroscopy and, in the case of 4, by X-ray crystallography. In addition, reaction of 1 with 1 equiv of [Cp*Ru(NCMe)(3)]OTf gave the product of displacement of one acetonitrile group from Ru, [Cp*Ru({eta (1)-Si((BuNCHCHNBu)-Bu-t-Bu-t)}(NCMe)(2)]OTf(5). Heating 5 in THF results in precipitation of a crystalline complex formulated as [Cp*Ru{eta (5):eta (1)-Si((BuNCHCHNBu)-Bu-t-Bu-t)}Cp*Ru(NCMe)(2)](OTF)(2) (6).