Dirhenium Complex Bearing a Metalated Caffeine Ligand: Synthesis, Crystal and Electronic Structures of [Re2(CO)8(µ,η1,κ1-C5N4(CH3)3O2}(µ-H)]

Abstract

Treatment of [Re2(CO)8(NCMe)2] with caffeine in boiling toluene produces the dirhenium hydrido-carbonyl complex [Re2(CO)8(µ,η1,κ1-C5N4(CH3)3O2}(µ-H)] (1) in low yield. Complex 1 is formed during this reaction through a C–H bond activation of caffeine at the imidazole ring. Crystal structure of 1, determined by XRD analysis, reveals that both the metalated caffeine and hydride act in bridging capacity by spanning across the rhenium-rhenium vector. The bonding in 1 has been confirmed by DFT calculations.