Clathrate directed assembly of tetrapyridyl-tetraphenylethylene metal-organic frameworks

Abstract

This work focuses on three 2-D MOFs based on the ligand tetrapyridyltetraphenylethylene (tppe) with the metal ions manganese(ii), nickel(ii) and copper(ii). These networks are all highly microporous with rhomboid channels measuring ∼14 × 17 Å giving approximately 49% solvent accessible void space. These voids are filled with ordered tetrachloroethylene (TCE) molecules that act as structure directing agents, and the structures remain porous even after removal of TEC molecules. The networks were characterised via single crystal X-ray diffraction, powder XRD, TGA, FTIR, fluorescence spectroscopy, and elemental analysis. Gas absorption measurements on the desolvated networks indicate that the networks are moderately selective, and their behaviour was typical of similar MOF networks. The Ni2+ based tppe-MOF exhibited greater capacity to absorb polar gases despite structural similarities to the other networks.