Wang X, Bai X, Lin H, Sun J, Wang X, Liu G. A series of new polyoxometalate-based metal-organic complexes with different rigid pyridyl-bis(triazole) ligands: assembly, structures and electrochemical properties.
RSC Adv 2018;
8:22676-22686. [PMID:
35539734 PMCID:
PMC9081470 DOI:
10.1039/c8ra03277g]
[Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 06/12/2018] [Indexed: 12/05/2022] Open
Abstract
Five new polyoxometalate (POM)-based metal-organic complexes (MOCs) with different rigid pyridyl-bis(triazole) ligands, namely, H{Co2(Hpyttz-I)2(H2O)6[CrMo6(OH)6O18]}·8H2O (1), {Co2(H2pyttz-I)2(H2O)4[TeMo6O24]}[Co(H2O)6]·3H2O (2), {Co3(Hpyttz-II)2(H2O)6[γ-Mo8O26]}·10H2O (3), {Ni3(Hpyttz-II)2(H2O)6[γ-Mo8O26]}·10H2O (4), {Ni3(Hpyttz-III)2(H2O)8[γ-Mo8O26]}·10H2O (5) (H2pyttz-I = 3-(pyrid-2-yl)-5-(1H-1,2,4-triazol-3-yl)-1,2,4-triazolyl, H2pyttz-II = 3-(pyrid-3-yl)-5-(1H-1,2,4-triazol-3-yl)-1,2,4-triazolyl, H2pyttz -III = 3-(pyrid-4-yl)-5-(1H-1,2,4-triazol-3-yl)-1,2,4-triazolyl), were successfully synthesized and structurally characterized by single-crystal X-ray diffraction, IR spectra, powder X-ray diffraction (PXRD) and thermogravimetric analyses (TGA). Complex 1 is a two-dimensional (2D) supramolecular network based on the binuclear complex unit: [Co2(Hpyttz-I)2(H2O)6 [CrMo6(OH)6O18]]. Complex 2 is a 1D supramolecular chain derived from the binuclear cobalt complex: {Co2(H2pyttz-I)2(H2O)4[TeMo6O24]}2-, the discrete [Co(H2O)6]2+ units act as counter cations. Complexes 3 and 4 are isostructural with different center metals (M = Co or Ni), the adjacent γ-Mo8O26 4- anions are linked by the MII ions to form a 1D M-γ-Mo8O26 inorganic chain. Then 1D M-γ-Mo8O26 inorganic chains are linked together by the 1D metal-organic M-(Hpyttz-II) chains to form a 3D framework. In complex 5, γ-Mo8O26 4- anions are bridged by the NiII ions to give a 1D Ni-γ-Mo8O26 inorganic chain, the adjacent 1D Ni-γ-Mo8O26 chains are connected through [Ni(Hpyttz-III)2] units to form a 2D layer. The effect of POM type and coordination site of the ligands on the structures of the title complexes were discussed. The title complexes 1, 2 and 5 exhibit excellent bifunctional electrocatalytic activities toward the reduction of bromate/hydrogen peroxide and the oxidation of ascorbic acid. In addition, the redox potentials of complexes 1, 2 and 5 are highly sensitive to pH and may be used as a kind of potential pH sensor.
Collapse