X-RAY STRUCTURAL-ANALYSES OF COPPER(I) AND SILVER(I) ADDUCTS OF THE RH(III) TRIHYDRIDE [(TRIPHOS)RHH3], WITH TRIPHOS=CH3C(CH(2)PPH(2))(3)

The two polyhydride complexes [(triphos)HRh(mu-H)(2)Cu(mu-H)(2)RhH(triphos)](+) (1) and [(triphos)HRh(mu-H)(2)Ag(mu-H)(2)RhH(triphos)](+) (2), where triphos is the tripod-like ligand CH3C(CH(2)PPh(2))(3), have been synthesized and characterized by X-ray analysis. They are isomorphous and crystallize in the tetragonal space group P4/n with Z=4 (a-20.508(8), c=21.021(8) Angstrom and V=8840.3 Angstrom(3) for 1 and a=20.670(7), c=20.501(9) Angstrom and V=8759.7 Angstrom(3) for 2). Their structures consist of nearly linear clusters with the arrays, Rh-Cu-Rh in 1 and Rh-Ag-Rh in 2, lying at angles of 170 and 168 degrees, respectively. The hydride ligands were not located by the X-ray analyses. Taking into account IR data and the arrangement of the heavy atoms the most likely positions for the bridging and terminal hydrides were obtained by methods of potential energy.