A Stable Silylene with a σ2, π- Butadiene Ligand

• Published in: Journal of the American Chemical Society 2017-05, Vol.139 (20), p.7117-7123
• Main Authors: Dong, Zhaowen, Reinhold, Crispin R. W, Schmidtmann, Marc, Müller, Thomas
• Format: Article
• Language: English
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.7b03566

The synthesis of a new type of silylene 1 is reported. It adopts a bicyclo[2.1.1]­hexene structure in which a hafnocene group is incorporated. The silylene is stabilized by homoconjugation with the remote CC double bond. This is indicated by its highly shielded 29Si NMR chemical shift (δ29Si = −155) and is firmly established by its experimental molecular structure from XRD analysis. The results of a detailed bonding analysis based on DFT calculations suggest for model compounds of silylene 1 and for its heavier germanium, tin, and lead homologues uniformly electronic structures of carbene analogues that are stabilized by homoconjugation. This stabilization mode is equivalent to a σ2, π-coordination of the butadiene ligand to the element atom as it is typical for zirconocene or hafnocene butadiene complexes.