Hydrothermal synthesis and characterization of one dimensional chain structures of monolacunary Keggin polyoxoanions substituted with copper

• [(4,4′bpyH2)2(4,4′bpyH)][PCuW11O39]·H2O and [4,4′bpyH2][pyH]3[PCuW11O39]·H2O were synthesized using hydrothermal method.
• The effect of pH of reaction media and stirring time are studied.
• Crystals were analysed using IR, TGA, magnetic measurements and X-ray diffraction.
• Molecules extends in 3D through hydrogen bonding.

Two novel polymeric polyoxometallates constructed from transition metal substituted heteropolytungstates, [(4,4′bpyH2)2(4,4′bpyH)][PCuW11O39]·H2O (1), and [(4,4′bpyH2)(pyH)3][PCuW11O39]·2H2O (2), (4,4′bpy = 4,4′bipyridine, py = pyridine) have been synthesized under hydrothermal conditions and characterized by IR, TGA, single crystal X-ray diffraction and magnetic measurements. The product formation showed a high sensitivity toward experimental factors including pH and stirring. Compounds 1 crystallizes in the monoclinic space group P2(1)/n with a = 13.503(3) Å, b = 26.726(5) Å, c = 15.168(3) Å, β = 99.61(3)° and Z = 4. The second compound also crystallizes in space group P2(1)/n, but with a = 13.519(3) Å, b = 20.431(4) Å, c = 18.655(4) Å, β = 96.52(3)° and Z = 4. Compound 1 exhibits a zigzag chain structure, while compound 2 exhibits a straight chain structure. Compound 2 is the first example of a polyoxometallate containing 1D chains of transition-metal-substituted heteropolytungstate designed with two significantly different organic units as the countercations. The Cu2+ ions in 1 exhibit paramagnetic behavior.

Two novel hybrid POMs based on the monolacunary Keggin anion [PCuW11O39]5− have been synthesized using hydrothermal methods and characterized using X-ray diffraction, IR, TGA and magnetic methods. Keggin units propagate as 1D chains in either a straight or a zigzag fashion.Figure optionsDownload as PowerPoint slide