Quaternization of the Bridgehead Nitrogen in Silatranylosmium(II) Complexes and Reestablishment of the Transannular N−Si Bond following Migratory Insertion of the Silatranyl Ligand

Abstract

The Si−N distance in the five-coordinate silatranyl complex Os(Si{OCH2CH2}3N)Cl(CQ)(PPh3)2 (1a, Q = O) is very long, and the geometry about nitrogen is planar. Accordingly, the nitrogen atom readily undergoes methylation or protonation, and this increases the Si−N separation even further. On addition of CO to 1b (Q = S), the coordinated CS inserts into the Os−Si bond and the normal silatrane N−Si interaction is restored in the (4).