Assembly, structures, electrocatalytic and photocatalytic properties of a series of Anderson-type polyoxometalate-based metal-organic complexes based on flexible pyridyl-amide ligands

Five new Anderson-type polyoxometalate-based metal-organic complexes, [Cu-4(mu(3)-oH)(2)(H2O)(6) (4-dpye)(2)(TeMo6O24)]center dot 2H(2)O (1), [Cu(4-dpyb)(CrMo6(OH)(6)O-18)(2)(H2O)(2)][Cu(4-dpyb)(H2O4](4-H(2)dpyb)center dot 6H(2)O (2), H[Cu-2(3-dpyb)(2)(C2O4)(CrMo6(OH)(6)O-18)]center dot 8H(2)O (3), [Cu-2(4-dpyh)(CrMo6(OH)(5)O-19)(H2O)(8)]center dot 10H(2)O (4) and [Cu-4(mu(2)-OH)(mu(3)-OH)(H2O)(6)(4-dpyh)(TeMo6O24)]center dot H2O (5) (4-dpye = N,N'-bis(4-pyridine carboxamide)-1,2-ethane, 4-dpyb = N,N'-bis(4-pyridinecarboxamide)-1,4-butane, 3-dpyb = N,N'-bis (3-pyridinecarboxamide)-1,4-butane, 4-dpyh = N,N'-bis(4-pyridinecarboxamide)-1,6-hexane), were hydrothermally prepared and structurally characterized by single crystal X-ray diffraction analyses and characterized by single-crystal X-ray diffraction, elemental analysis, IR, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA). Complex 1 is a 2D network, which is constructed from Cu-4-TeMo6 inorganic chains and 4-dpye ligands. Complex 2 contains two types of ID chains. Complex 3 shows a 1D ring-like chain structure, in which the CrMo6 anions act as fourfold monodentate ligands consolidating the [Cu-2(3-dpyb)(2)(C2O4)] rings. Complex 4 is a OD structure containing a dinuclear complex cation [Cu-2(4-dpyh)](4+) and discrete CrMo6 anion. Complex 5 exhibits a 3D framework constructed from 2D Cu-4-TeMo6 inorganic layer and 4-dpyh ligands. The spacer lengths and N-donor sites of the bis-pyridyl-bis-amide ligands, as well as different polyoxometalates play important roles in tuning the structures of the title complexes. The electrochemical behavior and electrocatalytic properties, as well as the photocatalytic activities of the title complexes have been studied. (C) 2017 Elsevier Ltd. All rights reserved.