Three-Dimensional Metal-Organic Frameworks Based on Functionalized Tetracarboxylate Linkers: Synthesis, Strucures, and Gas Sorption Studies

New tetracarboxylate ligands with dihydroxy (<b>L</b><sub><b>1</b></sub>) and crown ether functionalities (<b>L</b><sub><b>2</b></sub>) have been synthesized and treated with Cu<sup>II</sup> and Zn<sup>II</sup> ions to generate three-dimensional (3D) metal-organic frameworks (MOFs) with the compositions of [Cu<sub>2</sub>(<b>L</b><sub><b>1</b></sub>)(H<sub>2</sub>O)<sub>2</sub>]·14DMF·10H<sub>2</sub>O, <b>5</b>, [Cu<sub>2</sub>(<b>L</b><sub><b>2</b></sub>)(H<sub>2</sub>O)<sub>2</sub>]·12DMF, <b>6</b>, [Zn<sub>6</sub>(μ<sub>4</sub>-O)(<b>L</b><sub><b>1</b></sub>)<sub>2</sub>(<b>L</b><sub><b>1</b></sub>-H<sub>2</sub>)]·35DMF·27H<sub>2</sub>O, <b>7</b>, and [Zn<sub>3</sub>Na<sub>2</sub>(<b>L</b><sub><b>2</b></sub>)<sub>2</sub>(DMF)<sub>2</sub>]·7DMF·14H<sub>2</sub>O, <b>8</b>. The four compounds show different framework structures with different connectivities. Compound <b>5</b> exhibits the PtS topology whereas compound <b>6</b> has a [6<sup>4</sup>.8<sup>2</sup>]<sub>3</sub>[6<sup>6</sup>] topology. Compound <b>7</b> adopts a new [4.6<sup>5</sup>][4<sup>2</sup>.6<sup>8</sup>][4<sup>4</sup>.6<sup>2</sup>][4<sup>5</sup>.6][4<sup>8</sup>.6<sup>10</sup>.8<sup>3</sup>] topology while compound <b>8</b> exhibits the Flu topology. The porosity and H<sub>2</sub> uptake were studied by gas sorption experiments and grand canonical Monte Carlo (GCMC) simulations. Compound <b>5</b> shows a high H<sub>2</sub> uptake of up to 1.11 wt % at 77 K.