Synthesis and structure of a silyl–rhodium( I ) complex: stabilization attributable to multisite ‘anchoring’ of a silyl fragment

Reaction of SiH(CH2CH2PPh2)3(Htripsi) with [Rh(cyclo-octa-1,5-diene)Cl]2 affords [Rh(tripsi)H(Cl)](6) which on treatment with hydride then CO yields [Rh(tripsi)CO](4), a five-co-ordinate RhI complex characterized by single-crystal X-ray diffraction; silyl ‘cage’ co-ordination of Rh by tripsi is defined by Rh–Si at 2.379(5)Å and equatorial P attachment with the Rh atom 0.375 Å away from the P3 plane (i.e. Si–Rh–P ≈ 80°).