Rhenium multihydride heterobimetallic complexes containing bridging and chelating diphosphine ligands
Abstract
Treatment of the rhenium pentahydride complex [ReH5(dppen-PP′)(dppm-P)](dppen = Ph2PCHCHPPh2, dppm = Ph2PCH2PPh2) with 0.5 mol equivalents of [Rh2Cl2(cod)2](cod = cycloocta-1,5-diene) gave the fluxional bimetallic complex [(dppen-PP′)H3Re(µ-H)2(µ-dppm)Rh(cod)]Cl 1a, which was characterised as the corresponding PF6 salt 1b. Analogous complexes (1c and 1d) were prepared from [Rh2Cl2(nbd)2][nbd = norbornadiene (bicyclo[2.2.1 ]hepta-2,5-diene)]. The fluxionality of 1b and 1d was studied by 31P-{1H} and 1H NMR spectroscopies over a range of temperatures. Treatment of [ReH5(dppen-PP′)(dppm-P)] with silver iodide gave a fluxional rhenium–silver bimetallic complex formulated as [(dppen-PP′)H3Re(µ-H)2(µ-dppm)AgI] which was studied by variable-temperature NMR spectroscopy.