W-2(MU-H)(2)CL-4(MU-DPPM)(2) - THE BULK SYNTHESIS OF A BRIDGING HYDRIDE

The synthesis of the ditungsten species W-2(mu-H)(2)Cl-4(mu-dppm)(2) m arks the first bulk preparation of a bridging hydride W(III-III) speci es. The compound retains the characteristic edge-sharing bioctahedral (ESBO) geometry with a W--W bond distance of 2.3918(7) Angstrom. Altho ugh several Group VI ESBO complexes have been prepared, only two with bridging hydride groups, W-2(mu-H)(2)Cl-4(mu-dppm)(2) and W-2(mu-H)(2) (mu-O2CC6H5)(2) Cl-2(P(C6H5)(3))(2), have been reported to date. The c omplex W-2(mu-H)(2)Cl-4(mu-dppm)(2) has been characterized with P-31{H -1}, H-1 NMR, UV-vis, and IR spectroscopic techniques. A singlet is ob served in the P-31{H-1} NMR spectra of W-2(mu-H)(2)Cl-4(mu-dppm)(2) at delta = 20.464 ppm with J(P-W) = 126 Hz and the IR spectra includes t he tungsten-hydride symmetric stretch at 1602 cm(-1). (C) 1997 Elsevie r Science Ltd.