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.