Sandwich transitional metal complexes with tungstobismuthates and 1-methylimidazole ligands: Syntheses, structures and magnetic properties

Two novel sandwich-type coordination compounds of tungstobismuthate Na9[{Na(H2O)2}3{CoII(mim)}3(BiIIIWVI9O33)2]·36H2O (1) and Na7H2[{Na(H2O)2}3{MnII(mim)}3(BiIIIWVI9O33)2]·21H2O (2) (mim = 1-methylimidazole) have been synthesized in alkaline aqueous solution. Their composition and structures were established by elemental analyses, IR spectra, and single crystal X-ray diffraction. These two complexes consist of two tri-vacant [α-B-BiIIIWVI9O33]9− moieties linked through three CuII or MnII and three Na+ ions. These Na+ cations around the complex anion were bonded with some terminal and bridging oxo atoms from the complex anion and water molecules. In addition to tungstobismuthate ligands, 1-methylimidazoles also coordinate to sandwich transitional metal ions. Magnetic measurement indicates the existence of antiferromagnetic interaction between the trimeric transitional metal ions for 1 and 2.