Regulation of Redox Molecular Junctions in Covalent Organic Frameworks for H₂O₂ Photosynthesis Coupled with Biomass Valorization

Abstract

H 2 O 2 photosynthesis coupled with biomass valorization can not only maximize the energy utilization but also realize the production of value-added products.Here, a series of COFs (i.e. Cu 3 -BT-COF, Cu 3 -pT-COF and TFP-BT-COF) with regulated redox molecular junctions have been prepared to study H 2 O 2 photosynthesis coupled with furfuryl alcohol (FFA) photooxidation to furoic acid (FA). The FA generation efficiency of Cu 3 -BT-COF was found to be 575 mM g À 1 (conversion � 100 % and selectivity > 99 %) and the H 2 O 2 production rate can reach up to 187 000 μM g À 1 , which is much higher than Cu 3 -pT-COF, TFP-BT-COF and its monomers. As shown by theoretical calculations, the covalent coupling of the Cu cluster and the thiazole group can promote charge transfer, substrate activation and FFA dehydrogenation, thus boosting both the kinetics of H 2 O 2 production and FFA photo-oxidation to increase the efficiency. This is the first report about COFs for H 2 O 2 photosynthesis coupled with biomass valorization, which might facilitate the exploration of porous-crystalline catalysts in this field.

Full-color emission of fluorinated benzothiadiazole-based D–A–D fluorophores and their bioimaging applications

“…When the molar ratio of 1a and 2m was controlled as 1 : 1, the monosubstituted compound 3p was obtained by the Sonogashira reaction. Importantly, the molecular structure and purity of all obtained 3a-3p were well demonstrated by 1 H, 19 F, 13 C NMR, 27,28 HRMS (Fig. S1-S62, ESI †) and single-crystal X-ray diffraction analysis (for compounds 3e, 3f, 3m and 3p, Tables S1-S4, Fig.…”

“…By modifying the literature procedure, 25,26 FBTD derivatives 3a-3m and control compounds 3n-3p were successfully synthesized. All characterization data, such as 1 H, 13 C and 19 F NMR spectra as well as HRMS and single crystal data can be seen in the ESI. †…”

“…Meanwhile, it easily results in full-color fluorophores with tunable emission spectra from blue to red regions via incorporating diverse electron-donating units or extending the p-conjugated skeleton. 11,12 In recent reports, the BTD core has been successfully used; 13 especially, it can be developed into fullcolor metal-organic frameworks 14,15 or AIEgens 16 (Scheme 1(ii)). Although used as a building block with more electronwithdrawing nature, 17,18 5,6-difluoro-BTD (FBTD) has not been systematically exploited for multifunctional luminophores with full-color emission (Scheme 1(iii)).…”

Unlocking Synthesis of Polyhedral Oligomeric Silsesquioxane-Based Three-Dimensional Polycubane Covalent Organic Frameworks

“…As an emerging member of porous organic polymers, covalent organic frameworks (COFs) with controllable chemical and porous structures are promising for versatile applications, − including gas separation and storage, − catalysis, − energy conversion, − and so forth. COFs with diverse lattice topologies allow the two-dimensional (2D) or three-dimensional (3D) extension of polymer chains with regular micropores or mesopores .…”

Three-Motif Molecular Junction Type Covalent Organic Frameworks for Efficient Photocatalytic Aerobic Oxidation

“…The molecular junction catalyst, which refers to the molecular structure formed by two functional groups such as oxidative and reductive agents, is one of the ideal types of catalyst to fulfill the coupling reaction. The two-motif molecular junction catalysts were first developed in our recent studies, which innovatively realized the coupling of oxidative and reductive reactions in one system, and were successfully used for artificial photosynthesis, photocatalytic hydrogen peroxide synthesis, organic photocatalysis, and so on. − However, further implementation of three or more functional groups to break through the limitations of multifunctionality for two-motif molecular junction catalysts has not been studied. The functional groups such as photosensitizer units, electron transport units, redox catalytic centers, and so on can be simultaneously introduced to the molecular junction materials to couple efficient light absorption, photoelectron conversion, and highly active catalytic sites. − Therefore, the modulation of multifunctional catalysts can be realized on the basis of multiple-motif molecular junction materials.…”