Stabilization of a Silaaldehyde by its eta(2) Coordination to Tungsten

摘要

Treatment of pyridine- stabilized silylene complexes (eta(5)- C5Me4R)(CO)(2)(H)W= SiH(py)(Tsi) (R= Me, Et; py = pyridine; Tsi = C(SiMe3)(3)) with an N-heterocyclic carbene (IPr)-I-Me-Pr-i (1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) caused deprotonation to afford anionic silylene complexes (eta(5)- C5Me4R)(CO)(2)W= SiH(Tsi)(HIPr)-I-Me-Pr-i (R= Me (1-Me); R = Et (1- Et)). Subsequent oxidation of 1-Me and 1-Et with pyridine-N-oxide (1 equiv) gave anionic eta(2)- silaaldehydetungsten complexes (eta(5)- C5Me4R)(CO)(2)W{eta(2)-O=SiH(Tsi)}- (HIPr)-I-Me-Pr-i (R= Me (2-Me); R = Et (2- Et)). The formation of an unprecedented W- Si-O three-membered ring was confirmed by X- ray crystal structure analysis.