Mixed Transition Metal-Gold Cluster Hydrides

Article abstract of DOI:10.1021/ja00275a030

Four new transition metal-gold hydride compounds have been synthesized. (NO3)2 (1), PF6 (4) were made by the reaction of AuPPh3NO3 with Ru(H)2(dppm)2, BF4, and IrH(CO)(PPh3)3,respectively, and X (X=BF4, NO3 mixture) (5) was made by the reaction of PPh3 with BF4.Compounds 1 and 2 were characterized by single-crystal X-ray diffraction in the solid state <1, P1, a=15.022(4) Angstroem, b=19.247(5) Angstroem, c=14.783(5) Angstroem, α=104.64(2) deg, β=113.68(2) deg, γ=87.05(2) deg, T=-50 deg C, R=0.026; 2, P2₁2₁2₁, a=11.908(5) Angstroem, b=20.876(3) Angstroem, c=20.061(3) Angstroem, α=β=γ=90 deg, T=-50 deg C, R=0.041; and by (31)P and (1)H NMR spectroscopies in solution.In 1 the hydride ligands were directly observed by X-ray diffraction and are bridging the Ru to Au bonds.The average Ru-H and Au-H distances are 1.61(4) and 1.77(4) Angstroem, respectively, and the average Ru-Au and Au-Au separations are 2.781(0) and 2.933(0) Angstroem, respectively.In 2 the hydride ligands were not directly located but are thought to be dibridging the Ir to Au bond (2.699(0) Angstroem).In both compounds the bridging hydride formulations were confirmed by NMR andIR spectroscopies.In compounds 4 and 5 the hydride ligands are not interacting with Au but are terminally bonded to the Ir.In these latter compounds the Ir-H stretch was easily observed by IR spectroscopy <4, 2060 cm^-1; 5, 2080 cm^-1>, while no absorptions in the terminal hydride region were observed for 1 and 2.The bridging hydride region in the IR was obscured by other ligand absorptions, so bridging hydride vibrations were not observed.