Isolation of a Lewis acid-base stabilized stannanone

A diylide-substituted stannanone, stabilized by the Lewis acid SnCl 2 (formally written as Y 2 Sn=O→SnCl 2 ) has been successfully isolated and characterized by spectroscopic, crystallographic and computational methods. The nature of the ylide substituent proved critical for its successful isolation. While oxidation of a stannylene with a cyano-substituted ylide yielded only a dimeric stannoxane, incorporation of a thiophosphinoyl moiety provided sufficient steric bulk and additional stabilization through P=S coordination, enabling the isolation of the monomeric stannanone. Computational studies revealed a strongly polarized Sn-O bond with negligible π-contribution to the bonding interaction and high opposing charges, resulting in a short Sn-O linkage but a high reactivity toward bond cleavage. This study highlights the challenge associated with stabilizing formal multiple bonds with the heavier atoms and underscores the importance of substituent design in achieving such stabilization.