Synthesis of a thermally stable 2D MOF via neat grinding and annealing of a panel-like triangular ligand with Zn(ii)

Abstract

A new exotridentate ligand, 1,3,5-tris(2-methylpyridin-4-yl)benzene (mTPB), was synthesized and self-assembled with ZnBr₂ in the solid-state via mechanochemistry (i.e., neat grinding (NG)), followed by annealing. The amorphous phase generated by NG transformed into a crystalline structure corresponding to a 2D MOF (1) through an amorphous-to-crystalline transition. Compound 1 contains open 2D layers and exhibited thermal stablility up to 300 °C. Analogous 1,3,5-tris(pyridyl)benzene (TPB), upon NG, formed a poly-[n]-catenane of interlocked (M₁₂L₈) nanocages. This different behaviour was attributed to the presence of the methyl groups in the mTPB ligand.