Exploration of chemically cross-linked metal-organic frameworks.

A series of geometrically constrained, cross-linked benzene dicarboxylic acid (bdc) derivatives have been synthesized and incorporated into the canonical isoreticular metal-organic framework (IRMOF) lattice. Only certain cross-links, which allow for the proper relative orientation of the bdc subunits, form the desired IRMOF. Design criteria from these cross-linked ligands allowed for the rational design of two oligomeric ligands composed of three bdc monomers tethered together. These oligomeric ligands were also readily incorporated into an IRMOF lattice with a high degree of crystallinity and porosity, providing a new dimension to rational ligand design for metal-organic frameworks.