[MOO(NNPH2)(ACAC)2], A PRECURSOR OF NOVEL BINUCLEAR HYDRAZIDO(2-)MOLYBDENUM(VI) COMPLEXES CONTAINING BRIDGING ALKOXO LIGANDS - [(MOO(NNPH2)(ACAC)(MU-OR))2] - SYNTHESES, CHARACTERIZATION, REACTIVITY AND ELECTROCHEMICAL STUDIES - CRYSTAL-STRUCTURE OF [(MOO(NNPH2)(ACAC)(MU-OET))2]

1,1-Diphenylhydrazine reacts with [MoO2(acac)2] in methanol to yield either the mononuclear complex [MoO(NNPh2)(acac)2] (I) or the binuclear complex [{MoO(NNPh2)(acac)(mu-OMe)}2] (II) depending on the temperature. In refluxing ROH, complex I transforms into [{MoO(NNPh2)(acac)(mu-OR)}2]. (R = Me: II; R = Et: III; R = n-Pr: IV.) The crystal structure of III is reported. Crystals are triclinic, space group P1BAR, with unit cell dimensions a = 9.211(1), b = 10.375(2), c = 12.107(3) angstrom, alpha 72.98(2), beta = 64.55(1), gamma = 70.10(1)degrees and Z = 1. The structure was solved using 5034 unique observed reflections; the refinement of 304 variables gave R and R(w) values of 0.024 and 0.026, respectively. The lattice is made of discrete centrosymmetrical dinuclear molecules. The geometry of the hydrazido(2-) ligand (Mo-N = 1.784(1), N-N = 1.298(2) angstrom, Mo-N-N = 169.5(1)degrees) indicates extensive delocalization through the Mo-N-N unit. II, III and IV are representative members of a new family of dinuclear complexes which display the [(Ph2NN)OMo(mu-OR)2MoO(NNPh2)]2+ core.