Selective Carbanion-Pyridine Coordination of a Reactive P,N Ligand to RhI.

Abstract

Ligands with reactive carbon sites in the periphery of a metal center have emerged as a powerful approach for metal–ligand bond activation. These reactive carbon sites are commonly generated by deprotonation strategies. Carbon–silicon bond cleavage is a potential alternative to access such constructs. Herein, the monodesilylation of bis‐silyl‐substituted P,N scaffold PNSi2 in the coordination sphere of [RhI(Cl)(CO)(PNSi2)] (1) with sodium azide is disclosed. This affords a unique dinucleating anionic κ2‐C,N‐κ1‐P ligand with a carbanionic methine carbon atom directly bound to rhodium as part of a four‐membered Rh‐N‐C‐C rhodacycle. This dimer undergoes meta‐pyridine C−H activation facilitated by weak bases, which leads to a desymmetrization of the system and provides a σ,π‐bridging 3‐pyridyl fragment bound to RhI. The facile Si−C cleavage strategy may pave the way to studying the reactivity and functionalization of a variety of κ2‐C,N‐coordinated pyridine scaffolds for selective transformations.