Cycloheptatriene: a new versatile co-ordination ligand. Synthesis and structural characterization of [Ru6C(CO)17] derivatives

Abstract

The reaction of [Ru₆C(CO)₁₇] and cycloheptatriene (CHT) gives rise to the formation of several products which have been fully characterized in solution and by single-crystal X-ray diffraction as [Ru₆C(CO)₁₅(ENBD)] 1 (ENBD = ethylenenorbornadiene), [Ru₆C(CO)₁₄(C₇H₈)] 2 and [Ru₆C(CO)₁₁(η⁵-C₇H₉)(µ₃-η²∶η²∶η³-C₇H₇)] 3. Compounds 2 and 3 provide an example of the co-ordinative variability of carbocyclic rings based on the C₇-frame. The ligand in 1 contains nine carbon atoms and is formed from C₇H₉ by an unknown process. The CHT molecule has also been observed to convert to toluene through a ring contraction activated by the cluster to form the known compound [Ru₆C(CO)₁₄(η⁶-C₆H₅CH₃)] 4.