Syntheses, crystal structures, and properties of four polyoxometalate-based metal–organic frameworks based on Ag(I) and 4,4′-dipyridine-N,N′-dioxide
Haiyan Li, Hui Pan, Yanhua Fan, Yan Bai, Dong‐Bin Dang
Abstract
Four new metal–organic frameworks ([Ag<sub>3</sub>(dpdo)<sub>3.5</sub>(DMF)(PW<sub>12</sub>O<sub>40</sub>)]∙H<sub>2</sub>O (<strong>1</strong>), [Ag<sub>3</sub>(dpdo)<sub>5</sub>(DMF)<sub>2</sub>(PW<sub>12</sub>O<sub>40</sub>)]∙2CH<sub>3</sub>OH (<strong>2</strong>), [Ag<sub>3</sub>(dpdo)<sub>5</sub>(DMF)<sub>2</sub>(PMo<sub>12</sub>O<sub>40</sub>)]∙4H<sub>2</sub>O (<strong>3</strong>), and H<sub>0.5</sub>[Ag<sub>4.5</sub>(dpdo)<sub>5</sub>(DMF)(BW<sub>12</sub>O<sub>40</sub>)]∙5H<sub>2</sub>O (<strong>4</strong>); 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 <strong>1</strong> and <strong>4</strong>, the secondary building blocks ([Ag<sub>6</sub>O<sub>20</sub>] and [Ag<sub>3</sub>O<sub>14</sub>] for <strong>1</strong> and <strong>4</strong>, respectively) serve as nodes that connect the dpdo ligands with the polyanions ([PW<sub>12</sub>O<sub>40</sub>]<sup>3−</sup> and [BW<sub>12</sub>O<sub>40</sub>]<sup>5−</sup> for <strong>1</strong> and <strong>4</strong>, respectively) to create a three-dimensional (3D) framework. By joining Ag ions and dpdo ligands and enclosing the polyanions ([PW<sub>12</sub>O<sub>40</sub>]<sup>3−</sup> and [PMo<sub>12</sub>O<sub>40</sub>]<sup>3−</sup> for compounds <strong>2</strong> and <strong>3</strong>, respectively) as templates and counterions, compounds <strong>2</strong> and <strong>3</strong> display a two-dimensional (2D) gridlike network. Additionally, the solid state optical, luminescent, and ultraviolet–visible (UV–vis) spectral features of compounds <strong>1</strong>–<strong>4</strong> as well as the electrochemical characteristics of compounds <strong>1</strong>–<strong>3</strong> were examined.