Reactivity of [Ru3H2(CO)9(µ3-COMe){M(PPh3)}](M = Cu, Ag or Au) and [Ru3H(CO)9(µ3-PPh){Ag(PPh3)}] with PPh3

Abstract

Addition of PPh₃ to [Ru₃H₂(CO)₉(µ₃-COMe){Cu(PPh₃)}]1 results in rapid heteronuclear decapping to form the anion [Ru₃H₂(CO)₉(µ₃-COMe)]^–. A similar reaction occurs for the silver analogue 2 with excess of PPh₃. However a 1:1 reaction mixture affords [Ag(PPh₃)₄][{Ru₃H₂(CO)₉(µ₃-COMe)}₂Ag]5, which is stable in solution at low temperatures. NMR evidence is consistent with the anion having C₂ symmetry in which an approximately tetrahedrally co-ordinated silver centre links the two triruthenium clusters by edge bridging to each cluster. Reaction of [Ru₃H(CO)₉(µ₃-PPh){Ag(PPh₃)}]4 with PPh₃(1:1) affords an equilibrium mixture (at 173 K) of [Ru₃H(CO)₉(µ₃-PPh)]^–, 4, [Ag(PPh₃)_n]⁺(n= 3 and 4) and [{Ru₃H(CO)₉(µ₃-PPh)}₂Ag]^–. All these reactions are faster than the carbonyl substitution reactions which occur at room temperature.