SYNTHESIS AND REACTIVITY TOWARDS TETRAFLUOROBORIC ACID OF A NEW FAMILY OF HETEROBIMETALLIC POLYHYDRIDE COMPLEXES [(CO)(PPH(3))(2)HRE(MU-H)(3)RHL(2)] (L=PPH(3), 1,2,5-TRIPHENYLPHOSPHOLE, OR P(OME)(3))

The reaction of K[ReH6(PPh(3))(2)] with [RhCl(CO)L(2)] [L = PPh(3), 1, 2,5-triphenylphosphole (TPP), or P(OMe)(3)] leads to the new electroni cally unsaturated heterobimetallic polyhydride complexes [(CO)(PPh(3)) (2)HRe(mu-H)(3)RhL(2)] in moderate-to-good yields. The structures of t hese complexes have been established on the basis of spectroscopic dat a, especially H-1 and P-31 NMR. The bridging hydride ligands are fluxi onal but there is either a slow or nonexistent exchange between termin al and bridging hydrides. For L= PPh(3) or TPP, protonation with tetra fluoroboric acid affords quantitatively the cationic complexes [(CO)(P Ph(3))(2)HRe(mu-H)(3)RhHL(2)](+), isolated as the BF4- or the BPh(4)(- ) salts.