Interpenetrating 3D Covalent Organic Framework for Selective Stilbene Photoisomerization and Photocyclization

Abstract

The selective photoisomerization or photocyclization of stilbene to achieve value upgrade is of great significance in industry applications, yet it remains a challenge to accomplish both of them through a one-pot photocatalysis strategy under mild conditions. Here, a sevenfold interpenetrating 3D covalent organic framework (TPDT-COF) has been synthesized through covalent coupling between N,N,N,N-tetrakis(4-aminophenyl)-1,4-benzenediamine (light absorption and free radical generation) and 5,5′-(2,1,3-benzothiadiazole-4,7-diyl)bis[2-thiophenecarboxaldehyde] (catalytic center). The thus-obtained sevenfold interpenetrating structure presents a functional pore channel with a tunable photocatalytic ability and specific pore confinement effect that can be applied for selective stilbene photoisomerization and photocyclization. Noteworthily, it enables photogeneration of cisstilbene or phenanthrene with >99% selectivity by simply changing the gas atmosphere under mild conditions (Ar, Sele Cis . > 99%, Sele Phen . < 1% and O 2 , Sele Cis . < 1%, and Sele Phen . > 99%). Theoretical calculations prove that different gas atmospheres possess varying influences on the energy barriers of reaction intermediates, and the pore confinement effect plays a synergistically catalytic role, thus inducing different product generation. This study might facilitate the exploration of porous crystalline materials in selective photoisomerization and photocyclization.

Designing a binuclear copper center-incorporated photocatalyst to simulate enzyme catalysis in aerobic hydroxylation of phenylboronic acids

“…4c). 47 Cu(I)W–TPT has a more negative LUMO value than ˙O 2 − (ROS, E(O 2 /˙O 2 − ) = −0.33 V vs. NHE), indicating its potential to activate O 2 to ˙O 2 − for the oxidation of phenylboronic acid. 48…”

Missing-linker defects in a covalent organic framework photocatalyst for highly efficient synthesis of tetrahydroquinoline

“…Covalent organic frameworks (COFs), 19–22 an emerging class of crystalline, porous polymer materials, are constructed from molecular organic building units and joined by covalent bonds. Notably, the reticular chemistry of COFs with an ordered π-conjugated system allows accelerated migration of photogenerated charge carriers by channels and provides well-defined active sites for chemical reactions.…”

Molecular Design and Biomedical Application of AIEgens with Photochemical Activity

“…Therefore, DPE and its derivatives can serve as photochromic cores to create AIEgens with multiple photochemical activities (Scheme 1C). 37 In this Review, we mainly focus on the photochemical reactions and the biomedical application of AIEgens with photochemical activity. According to the photochemical pathways, three major categories of photochemical reactions are introduced: (i) reversible conformational photoisomerization; (ii) photocyclization; (iii) photodimerization, including the reaction mechanisms and concrete examples.…”

“…For instance, the rotation of Ph and torsion/twisting of CC under light irradiation can promote the photochemical reaction, which is also the basis of AIE phenomenon. Therefore, DPE and its derivatives can serve as photochromic cores to create AIEgens with multiple photochemical activities (Scheme C) . In this Review, we mainly focus on the photochemical reactions and the biomedical application of AIEgens with photochemical activity.…”