Stabilization of [Ru(bpy) 2(CO)( η1-CO 2)] and unprecedented reversible oxide transfer reactions from CO 32− to [Ru(bpy) 2(CO) 2] 2+ and from [Ru(bpy) 2(CO)( η1-CO 2)] to CO 2

Abstract

Unusual thermal stability of [Ru(bpy) 2(CO)( η 1-CO 2)] ( 1) as a metal– η 1 -CO 2 complex was examined both in solid state and in solution. Compound 1 dissolves in CH 3CN containing LiCF 3SO 3. Interaction between Li + and the η 1-CO 2 group enhances an electron flow from Ru to the CO 2 ligand and greatly contributes to the stabilization of the Ru– η 1-CO 2 bond. The reaction of [Ru(bpy) 2(CO) 2](PF 6) 2 with [Crown·K] 2CO 3 in dry CH 3CN selectively produced 1 through the 1:1 adduct with the RuC(O)–OCO 2 moiety. Stoichimetric formation of 1 from the 1:1 adduct is also assisted by [Crown·K] + as a Lewis acid. Similarly, the reaction of [Ru(bpy) 2(CO) 2](PF 6) 2 with (Me 4N) 2CO 3 in DMSO gave the 1:1 adduct in the initial stage, which gradually changed to a metalloanhydride complex, [Ru(bpy) 2(CO)((CO) 2O)] due to the absence of Lewis acids to stabilize 1, since an addition of LiCF 3SO 3 to the solution gave [Ru(bpy) 2(CO)( η 1-CO 2)] quantitatively.