SYNTHESIS AND CHARACTERIZATION OF NEW OCTAMOLYBDATES CONTAINING IMIDAZOLE, 1-METHYL-IMIDAZOLE OR 2-METHYL-IMIDAZOLE COORDINATIVELY BOUND TO MOLYBDENUM

The compounds [H2im]4[Mo8O26(Him)2] 1, [NH2Me2]4[Mo8O26(Him)2].3H2O 2, [1-Hmim]4[Mo8O26(1-min)2].2H2O 3 and [2-Hmim]4[Mo8O26(2-mim)2].3H2O 4 (where Him = imidazole, 1 -mim = 1-methylimidazole and 2-mim = 2-methylimidazole) have been synthesized. Compounds 1 and 3 were prepared by the reaction between molybdenum trioxide and imidazole or 1-methylimidazole in aqueous medium, whilst 2 and 4 were synthesized by reaction of molybdenum trioxide with imidazole or 2-methylimidazole in dmf-H2O (dmf = dimethylformamide). The compounds have been characterized by element analysis, infrared and H-1 and C-13 NMR spectroscopies and thermal measurements. The structures of compounds 2 and 3 were determined by X-ray crystallography and showed that both anions are composed of two MoNO5 and six MoO6 edge-sharing octahedra. The Mo-N and Mo-O bond strengths of both compounds have been calculated.