Facile cyclometallation of a mesitylsilylene: synthesis and preliminary catalytic activity of iridium(iii) and iridium(v) iridasilacyclopentenes.

Reactions of the mesityl-amidinato-silylene Si(tBu2bzam)Mes (1; tBu2bzam = N,N'-bis(tert-butyl)benzamidinato; Mes = mesityl) with three different iridium precursors led, at room temperature, to two iridium(iii) and one iridium(v) complexes featuring one (IrIII) or two (IrV) cyclometallated silylene ligands. The iridium(iii) complexes are active catalyst precursors for H/D exchange and dehydrogenative borylation of arene C-H bonds.