Effect of N-donor sites of bis-pyridyl-bis-amide ligands on the architectures of three Anderson-type polyoxometalate-based metal-organic complexes

Three polyoxometalate-based metal-organic complexes [Co-2(H2O)(6)(TeMo6O24)](3-H(2)dpyb)center dot 2H(2)O (1), [M-2(4-Hdpyb)(2)(H2O)(6)(TeMo6O24)]center dot 6H(2)O [M = Co (2), Zn (3); 3-dpyb = N,N '-bis(3-pyridinecarboxamide)-1,4-butane, 4-dpyb=N, N '-bis(4-pyridinecarboxamide)-1,4-butane] have been hydrothermally synthesized and characterized by elemental analysis, IR, TG, powder diffraction and single-crystal X-ray diffraction analysis. The structure of complex 1 consists of 1D [Co-2(H2O)(6)(TeMo6O24)] inorganic chains, which are joined together by the 3-dpyb ligands through weak hydrogen bonds to generate a 2D supramolecular network. Complexes 2 and 3 are isostructural; each [TeMo6O24](6-) (TeMo6) polyoxoanion chelates either two cobalt or two zinc atoms to generate the discrete complexes [Co-2(4-Hdpyb)(2)(H2O)(6)(TeMo6O24)] and [Zn-2(4-Hdpyb)(2)(H2O)(6)(TeMo6O24)], respectively. The electrochemical properties, electrocatalytic and photocatalytic activities of the complexes have been investigated.