Anchoring of cobalt, ruthenium, and osmium carbonyls to oxides by pendant thiol and phosphine ligands

Abstract

Thermal and photochemical anchoring of [Ru₄H₄(CO)₁₂] to phosphinated SiO₂ and Al₂O₃ afforded a mixture of mono- and di-substitution products. The species Os₃H(CO)₁₀[S(CH₂)₃Si(OMe)_{3 –x}(O–M′O_n)_x] can be formed either by interacting [Os₃H(CO)₁₀{S(CH₂)₃Si(OMe)₃}] with an oxide (M′O_n= SiO₂, Al₂O₃, TiO₂, SnO₂, ZnO, or MgO) or by reacting [Os₃(CO)₁₂] with HS(CH₂)₃Si(OMe)_{3 –x}(O–M′O_n)_x. Similar procedures carried out on the ruthenium analogue were less satisfactory due to its lower stability in contact with the oxides. Under similar conditions to those employed to react [M₃(CO)₁₂] with HS(CH₂)₃Si(OMe)_{3 –x}(O–M′O_n)_x, the carbonyl binds to the unfunctionalised oxide as M₃H(CO)₁₀(O–M′O_n) and/or oxidised metal carbonyl species. Surface protection by SiMe₃Cl or NH(SiMe₃)₂ is incomplete. The compound [Co₃(CO)₉(CSiCl₃)] reacts with the same six oxides (as powders) under mild conditions to afford the stable Co₃(CO)₉[CSiCl_{3 –x}(O–M′O_n)_x].