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

• A 2D supramolecular compound synthesized based on zwitterions and polyoxoanion.
• One of the carboxyl groups of the zwitterionic salt is esterified by methanol.
• Anions extend the linkage into a honeycomb-like layer via O⋯O interactions.
• The compound also shows attractive photochromism.
• The compound retains Keggin anion’s desulfurization activities.

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 = 2.432 mg/m3, μ = 2.262 mm−1, F(0 0 0) = 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 30 mg compound at 313 K for 15 min.

[C8H11N2O4]3PMo12O40·2CH3OH·H2O·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 = 2.432 mg/m3, μ = 2.262 mm−1, F(0 0 0) = 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.Figure optionsDownload as PowerPoint slide