Polynuclear complexes of main group and transition metals with polyaminopolycarboxylate and polyoxometalate

Six supramolecular compounds constructed by main group and transition metals, polyoxotungstates (SiW12O404-) and trans-N,N,N',N'-1,2-cyclohexanediaminotetraacetic acid (H(4)CyDTA), (NH4)(3)[Ni4Na-(H2O)(10)(CyDTA)(2)][SiW12O40]center dot 10H(2)O (1) (NH4)(2)[Cu3Na2(HCyDTA)(2)(H2O)(13)][SiW12O40]center dot 5H(2)O (2), (NH4)(2)[Zn-5(CyDTA)(2)(H2O)(16)][SiW12O40]center dot 8H(2)O (3), (NH4)(4)[Cd-4(CyDTA)(2)(H2O)(8)][SiW12O40] center dot 6H(2)O (4), (NH4) (4)[Sr-3(HCyDTA)(2)(H2O)(14)][SiW12O40](2)center dot H2O (5) and [Ca-4(H(2)CyDTA)(2)(H2O) (22)][SiW12O40]center dot 8H(2)O (6), were synthesized in aqueous solution and characterized by IR spectroscopy, thermogravimetric analysis and single-crystal X-ray diffraction techniques. Single-crystal structure analyses indicate they are constructed by the complexes with different nuclearity and polyoxometalates. In the sequence of Ni, Cu, Zn the nuclearity of the homometallic complex units increases from 2 to 5. Cadmium ions gives a tetranuclear complex with a compact structure. In 5 and 6 the main group metal ions and CyDTA form polymeric chains. CyDTA exhibits rather different coordination patterns to main group metal ions and transition metal ions due to their ionic radii and electronic configuration. The complex units and polyoxometalates arrange in different patterns due to the different shapes of the complex units. The compounds exhibit different thermal decomposition processes and the formation of compounds 3 and 4 quenches ligand-centered emissions and gives a ligand-to-metal emission. The study on various temperature susceptibilities of 1 and 2 shows that there is an antiferromagnetic coupling in the two compounds but coupling patterns are different.