STRUCTURAL AND SPECTROSCOPIC CHARACTERIZATION OF DITUNGSTEN HALIDE COMPOUNDS

The compound W-2(mu-H)(mu-O2CC6H5)Br-4(mu-dppm)(2) . 2THF (1) was synt hesized from W-2(mu-O2CC6H5)(4), dppm [bis(diphenylphosphino)methane], and Me(3)SiBr. The analogous reaction performed using Me(3)SiI result ed in the synthesis of W-2(mu-O2CC6H5)(2)I-2(mu-dppm)(2) . solvent (2) . The structures of both 1 and 2 were determined by X-ray crystallogra phy and the following data were obtained: 1, monoclinic P2(1)/c, No. 1 4, with a = 19.173(18) Angstrom, b = 15.104(9) Angstrom, c = 24.049(14 ) Angstrom, beta = 111.52(6)degrees, V = 6479(8) Angstrom(3), Z = 4, R 1 = 0.0776, and wR(2) = 0.1333; 2, monoclinic C2/m, No. 12, with a = 1 6.969(4) Angstrom, b = 19.189(4) Angstrom, c 12.195(4) Angstrom, beta = 127.28(2)degrees, V = 3159.6(14) Angstrom(3), Z = 2, R1 = 0.0326, an d wR(2) = 0.0657. Additional characterizations of both compounds were performed with P-31 NMR, H-1 NMR, UV-vis, and IR spectroscopy. Compoun d 2 and the other halide analogs can also be synthesized when ZnX(2) ( X = Cl, Br, and I) is used in the place of the silanes. The chloride a nd bromide analogs were characterized by P-31 NMR and UV-vis spectrosc opy.