Synthesis and characterization of new octamolybdates containing imidazole, 1-methyl- or 2-methyl-imidazole co-ordinatively bound to molybdenum

The compounds [H2im]4[Mo8O26(Him)2]1, [NH2Me2]4[Mo8O26(Him)2]·3H2O 2, [1-Hmim]4[Mo8O26(1-mim)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 elemental analysis, infrared and 1H and 13C 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.