Reaction Site Designation by Intramolecular Electric Field in Tröger's Base Derived Conjugated Microporous Polymer for Near-Unity Selectivity of CO 2 Photo-conversion.

To facilitate solar-driven overall CO 2 and H 2 O conversion into fuels and O 2 , a series of Tröger's base derived covalent microporous polymers are synthesized featuring flexural backbone and unusual charge transfer properties. The incorporation of rigid structural twist Tröger's base unit grants polymers enhanced microporosity and CO 2 adsorption/activation capacity. Density function theory calculations and photoelectrochemical analyses reveal that an electric dipole moment (from negative to positive) directed to the Tröger's base unit is formed across two obliquely opposed molecular fragments and induced an intramolecular electric field. The Tröger's base unit located at folding point becomes an electron trap to attract photogenerated electrons in the molecular network, which brings about carrier recombination suppression and designates the reaction site in synergy with the conjugated network. In response to the discrepancy in reaction pathways across the reaction sites, the product allocation in the catalytic reaction is hereby regulated. Optimally, CMP-nTB achieved the highest photocatalytic CO production of 163.53 μmol g -1 h -1 with approximately unity selectivity, along with H 2 O oxidation to O 2 in the absence of any photosensitizer or co-catalyst. This work provides a new insight for developing specialized artificial organic photocatalysts. This article is protected by copyright. All rights reserved.