Functionalization and Controlled Porosity within 3D Covalent Organic Frameworks

Functionalization and Controlled Porosity within 3D Covalent Organic Frameworks

3D Covalent Organic Frameworks (COFs) are porous, crystalline polymers with unique interpenetrated structures and large surface areas. Their structures allow for potential implementation in a variety of fields, including energy storage, catalysis, drug delivery and water purification. Specifically, 3D COFs’ interpenetrated structure provides a means to control pore size, which has been demonstrated with both porous and collapsed crystalline forms of the same network. In addition, the modularity of COFs provides the opportunity to vary functional groups through the systematic selection of starting materials. The addition of functional linkers to COF networks is vital for applications and optimizing the use of internal surface area, specifically in the case of purification through targeted molecule capture. However, common functionalization approaches for 2D COFs and metal organic frameworks (MOFs) are generally unsuccessful when applied to imine-linked 3D COFs. Here we explore the mechanism of 3D COF polymerization and crystallization to pursue a general approach for modular functionalization and controlled porosity. In particular, the different solubility of functionalized monomers has central importance for both optimizing conditions for COF crystallization as well as understanding the single crystal growth of small molecule analogs. We intend to ultimately develop a library of functional linkers and understand the impact of that functionality on both network growth and final porosity.