Structures, dynamic behaviour in solution and cross-coupling reactions of the α-palladiated (η6-alkylarene)tricarbonylchromium complexes containing a palladium-chromium bond

Article abstract of DOI:10.1016/s0020-1693(98)00207-2

Structures of the complexes (η³-C₃H₅)Pd(μ-ηn ^6:1-CH₂Ph)Cr(CO)₃ and (η³-C₃H₅)Pd[μ-η ^6:1-CH(Ph)Ph]Cr(CO)₃ in solution were evaluated by NMR (¹H and ¹³C) and IR spectroscopy. The dynamic behaviour of the complexes was investigated. Quick rotation (on the NMR time scale) of the tricarbonylchromium groups around the axis passing through the centre of the η⁶-coordinated phenyl ring and the chromium atom takes place at room temperature and becomes slow on cooling. The η³-allylic ligand was proved to undergo no dynamic changes in solution. Unlike the solid state, the semi-bridging carbonyl groups between chromium and palladium atoms are absent or very weak in solution. Cross-coupling reactions of the complexes with organohalides are described.