Triazole-derivatived ligands-directed diverse structures and polyaniline-assisted capacitive performances of two new Anderson-type [AlMo6(OH)6O18]3--based metal-organic complexes

Abstract

Two new polyoxometalate-based metal-organic complexes (POMOCs), namely, H{Zn2(Hpytty)2[AlMo6(OH)6O18](H2O)8}⸱6H2O (1), H{Zn2(Hpyttz)2[AlMo6(OH)6O18](H2O)8}⸱6H2O (2) , (H2pytty = 3-(pyrazin-2-yl)-5-(1H-1,2,4-triazol-3-yl)-1,2,4-triazolyl, H2pyttz = 3-(pyrid-2-yl)-5-(1H-1,2,4-triazol-3-yl)-1,2,4-triazolyl), were obtained under hydrothermal condition using different N-rich triazole-derivatived ligands and their characterization were identified through powder X-ray diffraction (PXRD), single-crystal X-ray diffraction, and infrared spectroscopy. Both the title POMOCsshow 2D supramolecular structures formed through hydrogen bonds, except that the [AlMo6(OH)6O18]3- anions in complex 2 are immobilized between the metal-organic unit via the coordination interaction. The capacitive performances of the carbon paper-based electrodes modified by complexes 1-2 were investigated, in which complex 2 achieve bigger specific capacitances of 1362 F·g-1 than that of 1 (1836 F·g-1) at the charge-discharge current density of 1 A·g-1. The enhancement of intramolecular bond strength is beneficial to improving the capacitance performance of complexes. In addition, after electrochemical conditioning with polyaniline, the electron-ion transfer rate, along with the pseudocapacitive activity of complexes 1-2 is also significantly improved.