A Visible‐Light‐Harvesting Covalent Organic Framework Bearing Single Nickel Sites as a Highly Efficient Sulfur–Carbon Cross‐Coupling Dual Catalyst

Abstract

Covalent Organic Frameworks (COFs) have recently emerged as light‐harvesting devices, as well as elegant heterogeneous catalysts. The combination of these two properties into a dual catalyst has not yet been explored. We report a new photosensitive triazine‐based COF, decorated with single Ni sites to form a dual catalyst. This crystalline and highly porous catalyst shows excellent catalytic performance in the visible‐light‐driven catalytic sulfur–carbon cross‐coupling reaction. Incorporation of single transition metal sites in a photosensitive COF scaffold with two‐component synergistic catalyst in organic transformation is demonstrated for the first time.

Ni-catalyzed C–S bond construction and cleavage

“…In 2021, the Voort group explored a visible light-harvesting covalent organic framework (COF) combined with a Ni( ii ) catalyst for the cross-coupling of C–S bonds to improve the catalytic efficiency and functional group compatibility (Scheme 20). 31 The triazine-based COF was used as both the photocatalyst and supporting material for nickel catalytic sites in their cross-coupling reaction. The connection between the photosensitive COF framework and the nickel catalytic center enabled the efficient transfer of electrons and thiol radicals to the nickel catalytic center, which significantly improved the catalytic efficiency.…”

Two-in-one metallaphotoredox cross-couplings enabled by a photoactive ligand

“…transcribed to other synthetically relevant transformations. In certain cases, some ligand-free inorganic metal salts [51][52][53][54][55][56][57][58] and metal-embedded organic frameworks [59][60][61][62][63][64][65][66][67] could achieve cross-couplings in the absence of external PCs, 68 although these systems remain underdeveloped and mostly limited to C-X bond formation.…”

A π-Conjugated Covalent Organic Framework Enables Interlocked Nickel/Photoredox Catalysis for Light-Harvesting Cross-Coupling Reactions

“…The activated internal (25) and terminal (26) olefins were also found to be compatible. Additionally, 3-phenylpropanoic acid (27), tetrahydro-2Hpyran-4-carboxylic acid (28), phenoxyacetic acid (29), and valproic acid (30) also steadily participated, delivering the C-O couple products in 49-78% yields. The reaction was also compatible with a range of aryl carboxylic acids having electronically biased functional groups (electron neutral, rich, and poor) at the ortho-, meta-, and para-position of the aryl ring.…”

“…[14][15][16][17][18][19] However, the field of COF-based photocatalysis is mainly dominated by solar energy sequestering proton and carbon dioxide reduction reactions, 20-2 25 even though COFs could be envisaged as a suitable platform to anchor a redox-active precatalyst and to be used as a sustainable sensitizer in light-mediated fine chemical synthesis. [26][27][28][29] Photocatalysis creates a sustainable alternative to harsh thermal conditions in chemical bond activation and bond-forming coupling reactions. [30][31][32] Recently, strategies employing nickel precursors combined with visible-light photocatalysis via photoredox, energy transfer, and charge transfer were used for forging carbon-carbon and carbon-heteroatom bonds.…”