Synthesis and structural characterization of a tetramolybdate, [Mo4O12(C8H6N4)]2-, containing a bridging phthalazine-1-hydraziado(2-) ligand. Comparison to the structure of [Mo4O10(OMe)2(NNMePh)2]2-, a tetramolybdate species exhibiting ligation to a terminal monodentate hydrazido(2-) group

Shahid N. Shaikh, Jon Zubieta

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The reaction of (n-Bu4N)2[Mo2O7] with 1-methyl-1-phenylhydrazine in CH2Cl2-methanol yields the tetranuclear poly oxomolybdate (n-Bu4N)2[Mo4O,10(OCH3)2(NNMePh)2] (I). Complex I displays the methoxy-bridged binuclear core [MoO(NNMePh)(μ- OCH3)2MoO(NNMePh)]2+, bridged by two double-bridging bidentate [MoO4]2- units. Complex I is structurally related to the class of tetranuclear poly oxomolybdates coordinated to small organic molecules, [Mo4O6-10L1L2]n-. The reaction of (n-BU4N)2[MO2O7] with the potentially chelating and bridging hydrazino ligand hydrazinophthalazine, H2NNH(C8H5N2) (H2NNH-pht), yields the analogous tetranuclear species (n-Bu4N)2[Mo4O12(HNN-pht)] (II). Although structurally related to I, II reveals a number of distinctive features. The binuclear core [Mo2O4(HNN-pht)]2+ displays a bridging oxo group and a bidentate bridging phthalazine moiety, in contrast to the two bridging methoxy groups of I. The Mo centers of this core are nonequivalent, one exhibiting [MoO4N2] coordination and the other [MoO5N], The bridging [MoO4]2- moieties display unexceptional geometry. The 17O NMR spectra of I, II, and the related 1,4-dihydrazinophthalazine derivative [Mo4O11(C8H6N6)]2- are consistent with the solid-state structures, exhibiting resonances in the regions assigned to doubly bridging Mo2O groups (350-450 ppm) and to terminal MoO groups (750-950 ppm). Crystal data follow. For I: monoclinic space group P21/c, with a = 9.770 (2) Å, b = 18.633 (3) Å, c= 16.706 (3) Å,β = 90.74 (1)°, V= 3041.0 (12) Å, Z = 2, and Dcalcd= 1.45 g cm-3; structure solution based on 1571 reflections converged at R = 0.0647. For II: triclinic space group PI, with a = 16.528 (2) Å, b = 17.631 (3) Å, c = 19.539 (4) Å, α = 88.90 (l)°,β = 87.00 (1)°, γ = 88.10 (1)°, V= 5682.2 (24) Å3, Z = 4, and Dcalcd= 1.43 g cm-3; structure solution based on 5429 reflections converged at 0.0689.

Original languageEnglish (US)
Pages (from-to)1896-1903
Number of pages8
JournalInorganic Chemistry
Issue number11
StatePublished - Jun 1 1988
Externally publishedYes


ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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