DINUCLEAR ORGANOHYDRAZIDO(2-)MOLYBDENUM(VI) COMPLEXES CONTAINING BRIDGING ALKOXO LIGANDS - [(MOO(NNMEPH)(ACAC)(MU-OR))2] - CRYSTAL-STRUCTURES OF [MOO(NNMEPH)(ACAC)2] AND [(MOO(NNMEPH)(ACAC)(MU-OPR-N))2]

1-Methyl-1-phenylhydrazine reacts with [MoO2(acac)2] in ROH (R = Me, Et, n-Pr) at room temperature, to yield [MoO(NNMePh)(acac)2] (I). In refluxing ROH under argon, complex I transforms into [{MoO(NNMePh)(acac)(mu-OR)}2] (R = Me(II), Et(III), n-Pr(IV)). The crystal structures of I and IV are reported. Crystals of I are monoclinic, space group P2(1)/c, with unit cell dimensions a = 8.442(1), b = 16.090(1), c = 13.875(1) angstrom, beta = 94,86(1)-degrees and Z = 4. The structure was solved using 2529 unique observed reflections. The refinement of 226 variables gave R and R(w) values of 0.024 and 0.026, respectively. The lattice is made of discrete mononuclear molecules. Crystals of IV are monoclinic, space group P2(1)/n, with a = 8.917(2), b = 21.728(3), c = 9.351(1) angstrom, beta = 107.83(2)-degrees and Z = 2. The final refinement of 200 variables gave R = 0.036 and R(w) = 0.039 for 2700 observed reflections. The lattice is made of discrete centrosymmetric dinuclear molecules. The geometries of the cis-[MoO(NNMeph)]2+ cores in I and IV are similar and indicative of multiple bonding. In I, Mo-O = 1.701(2), Mo-N = 1.789(3), N-N = 1.281(4) angstrom, Mo-N-N = 175.6(2), O-Mo-N = 102.8(1)-degrees; in IV, Mo-O = 1.693(3), Mo-N = 1.780(4), N-N = 1.292(6) angstrom, O-Mo-N = 101.8(2)-degrees.