Role of Temperature on Framework Dimensionality: Supramolecular Isomers of Zn<sub>3</sub>(RCOO)<sub>8</sub> Based Metal Organic Frameworks

Three new anionic metal organic frameworks, [Zn<sub>1.5</sub>(FDA)<sub>2</sub>(Me<sub>2</sub>NH<sub>2</sub>)]·<i>x</i>G (<b>1</b>), [Zn<sub>3</sub>(FDA)<sub>4</sub>(Me<sub>2</sub>NH<sub>2</sub>)<sub>2</sub>]·<i>x</i>G (<b>2</b>), and [Zn<sub>1.5</sub>(FDA)<sub>2</sub>(Me<sub>2</sub>NH<sub>2</sub>)]·<i>x</i>G (<b>3</b>) (FDAH<sub>2</sub> = 2,5-furandicarboxylic acid, G = guest), were synthesized solvothermally via a temperature tuning strategy. Compound <b>1</b>, synthesized at 90 °C, has a two-dimensional (2D) sheet structure, while <b>2</b> and <b>3</b>, synthesized at 120 and 160 °C, respectively, have three-dimensional (3D) structures. Compound <b>2</b> has alternating hydrophobic and hydrophilic channels with pore dimensions ∼4.3 × 4.4 Å<sup>2</sup> and ∼5.6 × 6.2 Å<sup>2</sup>, respectively. Compound <b>3</b> has only one type of pore with dimensions of ∼5.3 × 6.2 Å<sup>2</sup>. All three compounds have eight connected Zn<sub>3</sub>(RCOO)<sub>8</sub> nodes as building units and are anionic, with dimethyl ammonium cations present inside the channels to balance charge. Compounds <b>1</b>, <b>2</b>, and <b>3</b> are supramolecular isomers with general formula [Zn<sub>1.5</sub>(FDA)<sub>2</sub>(Me<sub>2</sub>NH<sub>2</sub>)]<sub><i>n</i></sub>.