Postsynthetic exchanges of metal-organic frameworks

Abstract

The replacements of framework metal ions and ligands were investigated in metal–organic frameworks (MOFs). The transmetalated MOFs could be obtained by soaking an MOF in the solution of a new replacing metal ion. By simply controlling the soaking time, not only fully transmetalated isostructural framework structure but also selectively transmetalated core-shell bimetallic structure could be prepared. The ligand exchanged MOFs could also be obtained via soaking an MOF in the solution of a new replacing ligand. By controlling the concentration of the replacing ligand, not only an entropically favorable MOF with completely exchanged ligand but also enthalpically favorable MOF with selectively exchanged ligand in the alternating layers could be obtained. While there is no significant structural rearrangement of the framework during the replacement of the framework metal ion, the replacement of the framework ligand led to the significant structural reorganization of the framework.