Asymmetric Diamine Synthesis for Covalent Organic Frameworks: Boosted Photocatalytic Performance by Restricting β‐Ketoenamine Bond Twist

Abstract

Abstract Covalent organic frameworks (COFs) are typically formed by the covalent bonding of geometrically symmetrical linkers. In this work, an asymmetric ( C 1h symmetry) amine linker (2,6‐diaminobenzothiazole) was employed to non‐linearly connect and synthesize the COFs (TpBa) featuring β‐ketoenamine bond, which lead to the discovery of interesting “angle‐induced restricted twist (AIRT)” effect. Compared with the COFs TpPa and TpDa with geometrically symmetrical linkers, the presence of asymmetric amine moieties in TpBa introduced certain angles between building blocks, mitigating the twist of the molecular plane caused by spatial steric hindrance on both sides of the β‐ketoenamine bonds thereby preserving the planar π‐conjugated system. Although TpDa exhibited a more favorable charges structure and distribution for separation and transport, TpBa demonstrated superior H 2 O 2 yield, suggesting the potential dominance of the AIRT effect under specific conditions. This work not only expands the option for COFs linker selection but also provides insights into boosting the photocatalytic performance of COFs.