Difunctionalised arene Ru6C cluster compounds with electron-withdrawing groups

Abstract

Thermolysis of [Ru₆C(CO)₁₇]1 with dimethyl cyclohexa-1,3-diene-1,4-dicarboxylate [C₆H₆(CO₂Me)₂-1,4] in dibutyl ether gave two isomeric cluster compounds [Ru₆C(CO)₁₄(η⁶-C₆H₄(CO₂Me)₂-1,4]2 and [Ru₆C(CO)₁₄(µ₃-η²:η²:η²-{C₆H₄(CO₂Me)₂-1,4)]3. The solid-state molecular structures of 2 and 3 have been established by low-temperature single-crystal X-ray diffraction analysis. These constitute the first example of co-ordination isomerism for the Ru₆C(CO)₁₄ unit with respect to a specific arene. In 2 the arene is η⁶ bonded to a single ruthenium atom whereas in 3 the arene is bonded in the µ₃ mode to a triangular Ru₃ face of the octahedral cluster unit. The solid-state structure of 3 is comprised of two rotamers along with two molecules of dichloromethane solvate. The solid-state architectures of 2 and 3 were also examined. The bifunctionalised arene ligand in 2 and 3 has the potential for further organic chemistry at these sites including possible copolymerisation with primary/secondary diamines.