Carbazolylene-Ethynylene Macrocycle based Conductive Covalent Organic Frameworks

Two covalent organic frameworks consisting of carbazolylene-ethynylene shape-persistent macrocycles with azine (MC-COF-1) or imine (MC-COF-2) linkages were synthesized via imine condensation. The obtained 2D frameworks are fully conjugated which imparts semiconducting properties. In addition, the frameworks showed high porosity with aligned accessible porous channels along the z axis, serving as an ideal platform for post-synthetic incorporation of I₂ into the channels to enable electrical conductivity. The resulting MC-COF-1 showed an electrical conductivity up to 7.8×10⁻⁴ S cm⁻¹ at room temperature upon I₂ doping with the activation energy as low as 0.09 eV. Furthermore, we demonstrated that the electrical properties of both MC-COFs are switchable between electron-conducting and insulating states by simply implementing doping-regenerating cycles. The knowledge gained in this study opens new possibilities for the future development of tunable conductive 2D organic materials.