Syntheses, structures, and properties of two new hybrid Dawson-based polyoxotungstates [Mn(2,2′-bipy)_3]H_2 [Mn(2,2′-bipy)_2][P_2W_(18)O_(62)] and [Co(H_2biim)_3)]_2H_2[P_2W_(18)O_(62)] ·8H_2O

摘要

Two new hybrid Dawson-based polyoxotungstates, [Mn(2,2′-bipy)_3]H_2[Mn(2,2′-bipy)_2][P_2W_(18)O_(62)] (1) and [Co(H_2biim)_3)]_2H_2[P_2W_(18)O_(62)] ·8H_2O (2) (2,2′-bipy=2,2′-bipyridine,H_2biim=2,2′-biimdazole), have been prepared under hydrothermal conditions and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, thermogravimetric analyses (TGA), X-ray photoelectron spectroscopy (XPS), and photoluminescence spectra. Compound 1 is a 1-D zigzag chain constructed from alternate Dawson-type heteropolyanions [α-P_2W_(18)O_(62)]~(6-) and metal coordination cations [Mn(2,2′-bipy)_2]~(2+), in which the 1-D chains are extended into a 3-D framework through C–H···π and π–π stacking interactions. Compound 2 is a discrete structure consisting of [α-P_2W_(18)O_(62)]~(6-) and two [Co(H_2biim)_3)]~(2+) cations, forming a 3-D supramolecular framework via N–H···O hydrogen bonds and C–H ···π interactions. Photoluminescence properties of 1 and 2 have been investigated at room temperature.