A novel 2D supramolecular compound of zwitterion and polyoxoanion and its application in catalytic desulfurization

Abstract

A novel 2D supramolecular compound based on the flexible zwitterion and Keggin-type polyoxoanion, formulated [C8H11N2O4]3PMo12O40·2CH3OH·H2O (compound 1) has been synthesized from the reaction mixture of 12-molybdophosphoric acid and the N,N′-diacetic acid imidazolium chloride under room temperature. Compound 1 crystallizes in the P2(1)/n space group of monoclinic system with a=13.1231(7), b=26.5393(14), c=20.0457(11)Å, α=13.1231(7), V=6833.7(6)Å3, C26H43Mo12N6O55P, Mr=2501.91, Dcalc=2.432mg/m3, μ=2.262mm−1, F(000)=4800, Z=4, R1=0.0522 and wR2=0.1242. X-ray crystallography shows that, under catalysis of the polyoxometalate anion, one of the carboxyl groups in each zwitterionic molecule is esterified by methanol solvent. The polyoxometalate anions extend to a honeycomb-like inorganic layer via short contact interactions of O⋯O. Compound 1 is employed as a catalytic oxidant to reveal its desulfurization behavior. The result shows that the supramolecular compound exhibits attractive photochromism. In addition, compound 1 retains Keggin molybdate anion’s desulfurization activities with 30mg compound at 313K for 15min.