Rational design of bimetallic sites in covalent organic frameworks for efficient photocatalytic oxidative coupling of amines

Songhu Shi; Wenhao Liu; Yujie Li; Shuanglong Lu; Han Zhu; Mingliang Du; Xin Chen; Fang Duan

doi:10.1016/j.jcis.2023.11.035

Rational design of bimetallic sites in covalent organic frameworks for efficient photocatalytic oxidative coupling of amines

J Colloid Interface Sci. 2024 Feb:655:611-621. doi: 10.1016/j.jcis.2023.11.035. Epub 2023 Nov 7.

Authors

Songhu Shi¹, Wenhao Liu¹, Yujie Li¹, Shuanglong Lu¹, Han Zhu¹, Mingliang Du¹, Xin Chen¹, Fang Duan²

Affiliations

¹ Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, PR China.
² Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, PR China. Electronic address: duanfang@jiangnan.edu.cn.

PMID: 37956548
DOI: 10.1016/j.jcis.2023.11.035

Abstract

The conversion of organic compounds by photocatalysis under mild conditions is an environment-friendly alternative for organic transformations. In this work, the bimetallic covalent organic framework coordinated by Sr²⁺ and Fe²⁺ in the porphyrin centers with molar ratio of 2:1 (COF-Sr2Fe1) was synthesized through a two-step reaction. Under the synergistic regulation of Sr²⁺ and Fe²⁺, the separation of photogenerated charges and visible light absorption for COF-Sr2Fe1 were significantly promoted, and thus COF-Sr2Fe1 exhibited efficient photocatalytic performance towards benzylamine oxidative coupling reaction with a yield of 97 %, much higher than that of the nonmetallic covalent organic framework COF-366. Moreover, it was found that the Fe site displayed higher dehydrogenation ability and the Sr site displayed higher CN coupling ability through the density functional theory (DFT) calculations, thereby making the dehydrogenation and CN coupling steps more controllable for benzylamine oxidative coupling reaction by COF-Sr2Fe1. This work provides a strategy for designing efficient covalent organic frameworks photocatalysts, and helps to understand the oxidative coupling of amines more deeply.

Keywords: Bimetallic sites; Conversion of organic compounds; Covalent organic frameworks; Photocatalysis; Synergistic effect.