Constructing Covalent Organic Polymers through Dative B─N Bonds: Synthesis, Single Crystal Structures, and Physical Properties

Abstract Growing single crystals of covalent organic polymers (COPs) for single‐crystal X‐ray diffraction analysis is very important and highly desirable because such strategy provides a deep understanding of crystallization kinetics and the structure‐property relationship of COPs. Based on the strategy that dynamic covalent bonds can allow self‐correction of structures during crystal growth, single crystals of two COPs (CityU‐15 and CityU‐16) based on dative boron‐nitrogen (B─N) bonds have been successfully obtained. Detailly, tetra(4‐pyridyl)tetrathiafulvalene (TTF(py)₄) and tetra(4‐pyridyl)porphine (TPYP) are employed as N‐donor ligands to react with 1,4‐bis(benzodioxaborole) benzene to prepare single crystals of COPs, named as CityU‐15 and CityU‐16, respectively. CityU‐16 exhibits enhanced stability compared to CityU‐15, and the size of CityU‐16 single crystals can reach up to 0.7 cm. CityU‐15 shows good recyclability and reveals noticeable photosensitivity upon iodine doping. After treatment with iodine, both crystals display obvious color changes. Specially, the device based on I₂‐treated CityU‐15 exhibits excellent low‐voltage operation and low energy consumption of 3.3 fJ, facilitating the development of artificial vision. This work highlights the successful introduction of functional groups into B‐N‐containing COPs, opening up new avenues for expanding their applications.