A BODIPY‐Based 1D Covalent Organic Framework for Photocatalytic Aerobic Oxidation

Abstract

Covalent organic frameworks (COFs) as metal‐free photocatalysts have attracted extensive interest. However, the organic transformations photocatalyzed by COFs under mild conditions remain a challenge. Herein, a boron‐dipyrromethene (BODIPY) based 1D COF, namely JNM‐12, was facilely constructed by Schiff‐base condensation reaction. JNM‐12 exhibited strong visible‐light harvesting abilities and suitable photocatalysis energy potentials, enabling the activation of O2 to superoxide anions (O2⋅−) and singlet oxygen (1O2) under visible light irradiation. Benefiting from these properties, JNM‐12 delivered excellent photocatalytic activity in the O2⋅−‐mediated oxidative coupling of amines and 1O2‐engaged aerobic oxidation of enamines. Our work paves a new way for synthesis of COFs as efficient, economical, and green photocatalysts for organic synthesis.

Novel Catalysis Systems for the Synthesis of Covalent Organic Frameworks

“…[85] This instability poses challenges in integrating them into COF structures. [86,87] Similarly, the susceptibility of thiol (À SH) groups to oxidation, [88][89][90] particularly at elevated temperatures, presents a hurdle. This often results in the need for intricate postmodification processes when incorporating the SH group into COF side chains.…”

Host–Guest Photosensitizer of a Cationic BODIPY Derivative and Cucurbit[7]uril for High-Efficiency Visible Light-Induced Photooxidation Reactions

“…For example, Hu and co-workers fabricated supramolecular assembly through host–guest interactions between water-soluble pillar[5]­arene and an aggregation-induced emission (AIE) photosensitizer, which exhibit the ability to effectively generate 1 O 2 and can be used as PCs for the conversion of dopamine to polydopamine . Li and co-workers reported a BODIPY-based one-dimensional covalent organic framework which not only has the ability to produce photoactive substances but also can be used to photocatalyze the oxidative coupling reaction of benzylamine . Chen and co-workers developed a BODPIY-based metal–organic framework that transforms from one-dimensional chains to two-dimensional layer structures, which can be used as an efficient visible light heterogeneous PC for the construction of C–B and C–C bonds .…”

A Spirobifluorene-Based Covalent Organic Framework for Dual Photoredox and Nickel Catalysis

“…To our knowledge, SCN is the first sp 2 -carbon conjugated 2D COF with staggered stacking . The staggered stacking introduced disorder and reduced the crystallinity of SCN …”

“…40 The staggered stacking introduced disorder and reduced the crystallinity of SCN. 35 X-ray photoelectron spectroscopy (XPS) showed that NiSCN had Ni(II) centers with Ni 2p 1/2 and 2p 3/2 peaks at 872.85 and 875.44 eV, respectively (Figure S3). Extended Xray absorption fine structure (EXAFS) analysis showed that the Ni centers in NiSCN adopted a tetrahedral coordination environment similar to that of Ni(bpy)Br 2 with two Ni−N bonds at 1.98 Å and two Ni−Br bonds at 2.35 Å (Figure 2d).…”

“…Based on the literature precedent of an imine-linked spirobifluorene COF, , we targeted the synthesis of SCN with a CC linkage from sp -CHO and bpy-CN building blocks. The CC linkages provide structural rigidity, improved stability, and enhanced energy/electron transfer .…”