RHENIUM MULTIHYDRIDE HETEROBIMETALLIC COMPLEXES CONTAINING BRIDGING AND CHELATING DIPHOSPHINE LIGANDS

Treatment of the rhenium pentahydride complex [ReH5(dppen-PP')(dppm-P) ] (dppen = Ph(2)PCH= CHPPh(2), dppm = Ph(2)PCH(2)PPh(2)) with 0.5 mol equivalents of [Rh2Cl2(cod)(2)] (cod = cycloocta-1.5-diene) gave the f luxional bimetallic complex [(dppen-PP')H3Re(mu-H)(2)(mu-dppm) Rh(cod) ]Cl 1a, which was characterised as the corresponding PF6 salt 1b. Anal ogous complexes (Ic and Id) were prepared from [Rh2Cl2(nbd)(2)] [nbd = norbornadiene (bicyclo[2.2.1]hepta-2,5-diene)]. The fluxionality of 1 b and 1d was studied by P-31-{H-1} and H-1 NMR spectroscopies over a r ange of temperatures. Treatment of [ReH5(dppen-PP')(dppm-P)] with silv er iodide gave a fluxional rhenium-silver bimetallic complex formulate d as [(dppen-PP')H3Re(mu-H)(2)(mu-dppm)Agl] which was studied by varia ble-temperature NMR spectroscopy.