Covalent Triazine Framework as an Efficient Photocatalyst for Regeneration of NAD(P)H and Selective Oxidation of Organic Sulfide

Abstract

Covalent triazine frameworks (CTFs), belonging to the super‐family of covalent organic frameworks, have attracted significant attention as a new type of photosensitizer due to the superb light‐harvesting ability and efficient charge transfer originating from the large surface area. However, the wide optical band gap in CTFs, which is larger than 3.0 eV, hinders the efficient light harvesting in the visible range. To overcome this limitation, we developed the new type CTFs photocatalyst based on the donor–acceptor conjugation scheme by using melamine (M) and 2,6‐diaminoanthraquinone (AQ) as monomeric units. The melamine‐2,6‐diaminoanthraquinone‐based covalent triazine frameworks (M‐AQ‐CTFs) photocatalyst shows the excellent light‐harvesting capacity with high molar extinction coefficient, and the suitable optical band gap involving the internal charge transfer character. Combination of M‐AQ‐CTFs and artificial photosynthetic system including the organometallic rhodium complex, acting as an electron mediator, exhibited the excellent photocatalytic efficiency for the regeneration of the nicotinamide cofactors such as NAD(P)H. In addition, this photocatalyst showed the high photocatalytic efficiency for the metal‐free aerobic oxidation of sulfide. This study demonstrates the high potential of CTFs photocatalyst with the donor–acceptor conjugated scheme can be actively used for artificial photosynthesis.

Phenyl Extended Naphthalene‐Based Covalent Triazine Frameworks as Versatile Metal‐Free Heterogeneous Photocatalysts

“…Elemental analyses, 1 H-NMR, 13 C-NMR, and fourier transform infrared spectroscopy (FT-IR) spectroscopy confirmed the structure of the novel dinitriles (for details, see Experimental Section, Table S1, Figure S1, S2, Supporting Information.…”

“…[7,8] The hydrogen evolution by water splitting has been the most studied photocatalytic reaction with CTFs-based polymers because CTFs have suitable bandgaps for this reaction and coupled with Pt yield good photocatalysts for the process. [9][10][11] CTFs have applied in photocatalytic organosynthesis for selective oxidation of alcohols, [12] dibenzyl sulfide, [13] photo-organosynthesis of phosphindole oxide, [14] or photo-reduction of nitrophenol. [15] Most of these CTFs photocatalysts were prepared from the di-or tetra-benzonitrile based on phenyl, biphenyl, or tetra-benzene structures.…”

Rational design of a graphitic carbon nitride catalytic–biocatalytic system as a photocatalytic platform for solar fine chemical production from CO2

“…A spectrophotometer (UV-1800; Shimadzu) was used to track regeneration of the NAD(P)H cofactor. 55,56…”

Solar light‐assisted rod‐shaped CPTF @ FACC photocatalyst: An efficient platform for oxygenation reactions and coenzymes regeneration

“…1 The solar energy conversion via mimicking natural photosynthesis route is an efficient pathway that develops a sustainable artificial system for coenzyme's regeneration that is, reduced form of nicotinamide adenine dinucleotide (NADH) or its phosphorylated form (NADPH). [27][28][29][30][31] The regenerated coenzyme's act as a hydrogen and electron donor in solar energy-based enzymatic reactions. [32][33][34] However, the high cost of coenzyme's preventing the production of novel energy in the field of industrial enzymatic application, this is because NADH/NADPH itself oxidized into NAD + /NADP + during the enzymatic reaction.…”

“…Moreover, solar light‐assisted artificial photocatalysis is broadly employed in the field of energy conversion and storage 1 . The solar energy conversion via mimicking natural photosynthesis route is an efficient pathway that develops a sustainable artificial system for coenzyme's regeneration that is, reduced form of nicotinamide adenine dinucleotide (NADH) or its phosphorylated form (NADPH) 27‐31 . The regenerated coenzyme's act as a hydrogen and electron donor in solar energy‐based enzymatic reactions 32‐34 .…”