TRANSITION-METAL-SILYL COMPLEXES .38. SYNTHESIS OF PHOSPHANE SUBSTITUTED HYDRIDOSILYL COMPLEXES OF CHROMIUM, MOLYBDENUM AND TUNGSTEN, (CO)5-N(R'3P)NM(H)SIR3 (N=2,3) AND SYNTHESIS OF (CO)3(L-L)M(H)CL BY CONVERSION OF (CO)3(L-L)M(NCR') WITH HSICLR2 [L-L=TMEDA, BIPY, DPPE, (PPH3)2]

At least two phosphorus atoms at the metal (n greater-than-or-equal-to 2) are necessary to obtain stable hydrido-silyl complexes of the type (CO)5-n(R'3P)(n)M(H)SiR3 (M = Cr, Mo, W). The complexes (CO)3(dppe)M(H)SiR3 and (CO)2(tdppme)M(H)SiR3 are obtained either by photochemical reaction of (CO)4(dppe)M or (CO)3(tdppme)M, or by thermal reaction of (CO)4(dppe)M(THF) with silanes HSiR3. Reaction of the isonitrile complexes (CO)3(L-L)M(NCR') (M = Mo, W; L-L = tmeda, bipy, dppe, (PPh3)2) with silanes HSiR2Cl does not yield hydrido-silyl complexes, but instead the hydrido-chloro complexes (CO)3(L-L)M(H)Cl. The latter complexes were also prepared by reaction of (CO)3(L-L)M(NCR') with HCl for comparison. The molecular structure of (CO)3(dppe)W(H)Cl was determined by an X-ray structure analysis. The complex has a capped-octahedral geometry with a facial arrangement of the three CO ligands and the hydride ligand above the triangular face formed by the two phosphorus atoms and a CO ligand.