Reactions of ReH3(CO)(PMe2Ph)(3) with metallic Lewis acids. Synthesis and structural characterization of hydride-bridged heterometallic rhenium-gold,rhenium-silver, and rhenium-copper complexes

This contribution presents a study of the reactions of ReH3(CO)(PMe2Ph)(3) (1) with a variety of metallic Lewis acids of the coinage metals to form hy drido-bridged heterometallic rhenium-gold, rhenium-silver, and rhenium-copp er complexes. The reaction of 1 with AuCl(PPh3) proceeds with elimination o f hydrogen to give the hydride-bridged heterobinuclear rhenium-gold complex (PMe2Ph)(3)(CO)ClRe(mu-H)Au(PPh3) (2). In contrast, the reactions of 1 wit h AgPF6, [Cu(CH3CN)(4)]PF6 or CuCl proceed without elimination of hydrogen to give the hydride-bridged heterotrinuclear rhenium-silver and rhenium-cop per complexes [(PMe2Ph)(3)(CO)HRe(mu-H)(2)M(mu-H)(2)ReH(CO)(PMe2Ph)(3)]PF6 (M = Ag (3), Cu (4)) and the hydride-bridged heterotetranuclear rhenium-cop per complex (PMe2Ph)(3)(CO)HRe(mu-H)(2)Cu(mu-Cl)(2)Cu(mu-H)(2)ReH(CO)(PMe2P h)(3) (5), respectively. The molecular structures of compounds 2 and 3 have been determined by single-crystal X-ray diffraction studies. Crystallograp hic data for 2: monoclinic, space group P2(1)2(1)2(1), a=12.804(2) Angstrom , b=13.512(2) Angstrom, c=24.312(3) Angstrom, V=4206(1) Angstrom(3), Z = 4, and R = 0.042. Crystallographic data for 3: monoclinic, space group C2/c, a = 24.212(6) Angstrom, b = 13.098(3) Angstrom, c = 20.177(5) Angstrom, b=1 16.40(2)degrees, V=5732(2) Angstrom(3), Z=4, and R=0.044. The X-ray crystal structure of 2 exhibits a short contact (2.798(12) Angstrom) between the g old atom and the CO ligand that is primarily bound to the adjacent rhenium atom, suggesting an incipient semibridging relationship.