Novel mixed-valence heteropolyoxometalates:: A molybdenum diphosphonate anion [MoV7MoVIO16(O3PPhPO3H)4]3- and its one- and two-dimensional assemblies

A novel mixed-valence polyoxomolybdenum anion, [(Mo7MoO16)-Mo-V-O-VI(O3PPhPO3H)(4)](3-), was synthesized hydrothermally from molybdenum oxide, molybdenum metal, boric and phosphoric acids, 1,2-phenyldiphosphonic acid, and imidazole (ImH) and was structurally characterized as an imidazolium salt (orthorhombic, Aba2; a = 16.674(4), b = 17.238(1), and c = 24.81(2) Angstrom). One- and two-dimensional structures of this anion and additional molybdenum diphosphonate linkers were assembled as well. They were structurally characterized as their pyridinium (pyH) salts (pyH)(4)[{(Mo7MoO16)-Mo-V-O-VI(O3PPhPO3)(2)(O3PPhPO3H)(2)}{Mo2O4(OH)(HO3PPhPO3H)}].5H(2)O (monoclinic, P2(1)/c; a = 20.8506(9), b = 22.866(1), and c = 21.1403(9) Angstrom; beta = 118.7087(8)degrees) and (pyH)(3)[{(Mo7MoO16)-Mo-V-O-VI(O3PPhPO3)(4)}{Mo2O2(OH)(2)(HO3PPhPO3H)}].3H(2)O (orthorhombic, Pca2(1); a = 19.057(1), b = 20.402(2), and c = 20.660(2) Angstrom). The compounds were also characterized by IR spectroscopy and magnetic measurements.