Evidence for the ready insertion of rhodium into a carbon–hydrogen bond of ethylene; crystal and molecular structure of µ-but-2-ene-µ-ethylene-bis-(η5-1-methylindenyl)dirhodium

Abstract

But-2-yne reacts with [Rh(C₂H₄)₂(η⁵-C₉H₇)] or [Rh(C₂H₄)₂(η⁵-1-MeC₉H₆)] to give respectively [Rh₂(CHCH₂)(CMeCHMe)(η⁵-C₉H₇)₂], [Rh₂(C₄Me₄)(η⁵-C₉H₇)₂], [Rh₂(CHCH₂)(CMeCHMe)(η⁵-1-MeC₉H₆)], and [Rh₂-(C₄Me₄)(η⁵-1-MeC₉H₆)₂] the structure of the 1-methyl analogue of the divinyl complex being established by X-ray crystallography; treatment of the dirhodium divinyl complex with carbon monoxide affords [Rh(CO)₂(η⁵-C₉H₇)] and the ketone CH₂CH·COC(Me)C(H)Me.