Syntheses, crystal structures, and properties of four polyoxometalate-based metal–organic frameworks based on Ag(I) and 4,4′-dipyridine-N,N′-dioxide

Abstract

Four new metal–organic frameworks ([Ag3(dpdo)3.5(DMF)(PW12O40)]∙H2O (1), [Ag3(dpdo)5(DMF)2(PW12O40)]∙2CH3OH (2), [Ag3(dpdo)5(DMF)2(PMo12O40)]∙4H2O (3), and H0.5[Ag4.5(dpdo)5(DMF)(BW12O40)]∙5H2O (4); dpdo = 4,4'-dipyridine-N,N'-dioxide) based on polyoxometalates were created, and their properties were examined using infrared (IR) spectroscopy, powder X-ray diffraction, elemental analysis, and comprehensive single-crystal structure investigations. In compounds 1 and 4, the secondary building blocks ([Ag6O20] and [Ag3O14] for 1 and 4, respectively) serve as nodes that connect the dpdo ligands with the polyanions ([PW12O40]3− and [BW12O40]5− for 1 and 4, respectively) to create a three-dimensional (3D) framework. By joining Ag ions and dpdo ligands and enclosing the polyanions ([PW12O40]3− and [PMo12O40]3− for compounds 2 and 3, respectively) as templates and counterions, compounds 2 and 3 display a two-dimensional (2D) gridlike network. Additionally, the solid state optical, luminescent, and ultraviolet–visible (UV–vis) spectral features of compounds 1–4 as well as the electrochemical characteristics of compounds 1–3 were examined.

Keywords

• polyoxometalates
• metal–organic frameworks
• electrocatalysis
• crystal structures