Engineering Screw Dislocations in Covalent Organic Frameworks

We report the application of a Pictet-Spengler reaction to the synthesis of covalent organic frameworks (COFs) using functionalized terephthalaldehydes. The COFs produced show an increased propensity to generate screw dislocations and produce multilayered flakes when compared with other 2D-COFs. Using HRTEM, definitive evidence for screw dislocations was obtained and is presented. The effects on separations using these materials in membranes are also reported.