SYNTHESIS, STRUCTURE, AND CHARACTERIZATION OF N-LIGATED TUNGSTEN SELENIDE CLUSTER COMPLEXES W(6)SE(8)L(6)

Two new W6Se8 cluster units are reported via the reaction of W6Cl12 wi th Na2Se in the refluxing amine solvents pyridine (py) and piperidine (pip). Crystals for both complexes were grown from the reaction filtra tes. Crystallographic data for these complexes are as follows: W6Se8(p ip)(6) . 8pip (1), cubic, <1(4)over bar 3d>, a = 31.150(4) Angstrom, Z = 12; W6Se8(py)(6) . 6py (2), trigonal, <R(3)over bar>, a = 19.654(2) Angstrom, c = 15.100(5) Angstrom, Z = 3. W-W and W-Se bond distances show little variation among the complexes with average values of 2.691 (1) and 2.574(1) Angstrom, respectively. Photoelectron spectra give ch aracteristic tungsten binding energies at 30.8 eV (W 4f(7/2)) and 32.9 eV (W 4f(5/2)). IR spectra show strong bands at 243-254 cm(-1), attri butable to the T-Iu W-Se stretching modes.