N‑Heterocyclic Silyl Pincer Ligands

The reaction of 1,2-C₆H₄(NHCH₂PPh₂)₂ with chlorosilanes Cl₂SiHR (R = Ph, Cl) affords the benzosiladiazoles RHSi­(NCH₂PPh₂)₂C₆H₄ (R = Ph, 1; Cl, 2). The phenyl derivative 1 undergoes chelate-assisted Si–H activation with [RuPhCl­(CO)­(PPh₃)₂] and [RhCl­(PPh₃)₃] to afford the structurally characterized silyl pincer complexes [RuCl­(CO)­(PPh₃)­{κ³-P,Si,P′-SiPh­(NCH₂PPh₂)₂C₆H₄}] (3) and [RhHCl­(PPh₃)­{κ³-P,Si,P′-SiPh­(NCH₂PPh₂)₂C₆H₄}] (4). The reaction of 4 with [Et₂NH₂]­[S₂CNEt₂] affords the complex [RhH­(S₂CNEt₂)­{κ³-P,Si,P′-SiPh­(NCH₂PPh₂)₂C₆H₄}] (5), structural data for which demonstrate a pronounced trans influence for the σ-silyl donor.