2-Indenylidene pincer complexes of zirconium and palladium.

[IndH(2)(Ph(2)P=X)(2)] derivatives (1, X = NMes; 4, X = S) react with [Zr(NMe(2))(4)] and [PdCl(2)(cod)] to afford the complexes {[Ind(Ph(2)PNMes)(2)]Zr(NMe(2))(2)} (3), {[Ind(Ph(2)PS)(2)]Zr(NMe(2))(2)} (5), and {[Ind(Ph(2)PS)(2)]Pd(HNc-Hex(2))} (7). The ability of the phosphazene and thiophosphinoyl side arms to support the coordination of the indenyl ring as 2-indenylidene was evidenced by NMR spectroscopy and X-ray diffraction studies. Analysis of the bonding situation by density functional theory calculations revealed a strong sigma interaction but a negligible (if any) pi interaction between C2 and the metal.