Electronic structures of two-dimensional covalent organic frameworks based on a series of period 4 transition metal phthalocyanines and ethynyl moieties

Abstract

Metal–phthalocyanine-based covalent organic frameworks (MPc COFs) could be used to construct fully π-conjugated systems. MPcs linked via the –CC– group are ideal two-dimensional (2D) monolayer networks. The 2D π-conjugated systems would be beneficial for photo-/electrocatalysis. Herein, we generally performed theoretical calculations on the electronic structures of 2D MPc (M = Ti, Mn, Fe, Co, Ni, Cu, and Zn) COFs linked via the –CC– moiety. The FePc and CoPc COFs possess higher catalytic activity than the others. ELF (electron localization function) and COHP (crystal orbital Hamilton population) analyses reveal that the isoindole rings in the Pc moiety allow electron conduction, which enhances the charge transfer inside Pc and also the electron transfer between the unit cells of the MPc COFs. Thus, Pc is a good substrate for metal-based active site-catalyzed reactions.