Coordination Covalent Frameworks: A New Route for Synthesis and Expansion of Functional Porous Materials

The synthetic approaches for fine-tuning the structural properties of coordination polymers or metal organic frameworks have exponentially grown during the past decade. This is due to the control over the properties of the resulting structures such as stability, pore size, pore chemistry and surface area for myriad possible applications. Herein, we present a new class of porous materials called Coordination Covalent Frameworks (CCFs) that were designed and effectively synthesized using a two-step reticular chemistry approach. During the first step, trigonal prismatic molecular building block was isolated using 4-aminobenazoic acid and Cr (III) salt, subsequently in the second step the polymerization of the isolated molecular building blocks (MBBs) takes place by the formation of strong covalent bonds where small organic molecules can connect the MBBs forming extended porous CCF materials. All the isolated CCFs were found to be permanently porous while the discrete MBB were nonporous. This approach would inevitably open a feasible path for the applications of reticular chemistry and the synthesis of novel porous materials with various topologies under ambient conditions using simple organic molecules and versatile MBBs with different functionalities that would not be possible using the traditional one-step approach.