Synthesis of di-rhodium complexes containing s-cis-bridging 1,3-diene ligands: X-ray crystal and molecular structure of µ-(η4-cyclohexa-1,3-diene)-µ-carbonyl-bis-(η5-indenyl)dirhodium(Rh–Rh)

Reaction of [Rh3(µ-CO)3(η5-C9H7)3] with buta-1,3-diene, trans-penta-1,3-diene. isoprene, trans, trans- hexa-2,4-diene, cyclopentadiene, and cyclohexa-1,3-diene affords the stable complexes [Rh2(µ-CO)(µ-1,3-diene)(η5C9H7)2]; an X-ray crystallographic study of the cyclohexa-1,3-diene complex shows that the diene is more weakly held than in mononuclear systems.