Products of the reaction of Re2(CO)10 with methanolic KOH. The crystal and molecular structure of the trimethylbenzylammonium salt of hexa-μ2-hydridodecacarbonyl-tetrahedro-tetrarhenate(2-)

The compound (Me3BzN)2[H6Re4(CO)12] (Bz = benzyl) crystallizes in the monoclinic space group P21 c with a 10.03(1), b 20.52(2), c 19.47(2) Å, β 96.30(8)°, Z = 4. Diffractometer data have been refined by least-squares methods to a final R of 5.1% for 1334 independent reflections. The anion contains a regular metal atom tetrahedron (mean ReRe 3.157 Å); it is not disordered, in contrast with the situation in its (AsPh4)+ salt. The ReC and CO interactions have mean values of 1.81 and 1.21 Å. The MMC angles are significantly larger, and the CMC angles smaller, than in Ir4(CO)12, confirming the presence of the edge-bridging hydrido ligands on the six ReRe bonds. The metal-metal interactions in the various known structures of polynuclear carbonylic species of rhenium are discussed. © 1977.