Asymmetric Covalent Triazine Framework for Enhanced Visible‐Light Photoredox Catalysis via Energy Transfer Cascade

Abstract

Complex multiple-component semiconductor photocatalysts can be constructed that display enhanced catalytic efficiency via multiple charge and energy transfer, mimicking photosystems in nature. In contrast, the efficiency of single-component semiconductor photocatalysts is usually limited due to the fast recombination of the photogenerated excitons. Here, we report the design of an asymmetric covalent triazine framework as an efficient organic single-component semiconductor photocatalyst. Four different molecular donor-acceptor domains are obtained within the network, leading to enhanced photogenerated charge separation via an intramolecular energy transfer cascade. The photocatalytic efficiency of the asymmetric covalent triazine framework is superior to that of its symmetric counterparts; this was demonstrated by the visible-light-driven formation of benzophosphole oxides from diphenylphosphine oxide and diphenylacetylene.

Exploring the “Goldilocks Zone” of Semiconducting Polymer Photocatalysts by Donor–Acceptor Interactions

“…[8] Moreover, D-A dyads with sulfur-containing donor groups and electronegative (nitrogen-and oxygen-containing) acceptor groups enable very narrow band gaps, [9] tuning of emitted colour, [10] and enhanced photoluminescence. Fore xample,aphotoactive triazine-containing D-A polymer was successfully used for photocatalytic conversion of organic molecules.…”

Covalent Organic Frameworks: Chemical Approaches to Designer Structures and Built‐In Functions

“…Asymmetric CTFs with four different donor-acceptor units (Figure 44 a) exhibit extended absorption, enhanced energy transfer, and enhanced charge-carrier mobility.T hese CTFs catalyze the formation of benzophosphole oxide with yields of up to 95 %and they are applicable to aw ide range of functional groups. [183] Theb enzoxazolelinked COF LZU-190 (Figure 44 b) has outstanding stability upon exposure to sunlight or under conditions such as strong acids (9 m HCl) and strong bases (9 m NaOH). LZU-190 catalyzes the aerobic oxidation of av ariety of arylboronic acids to phenols in excellent yields (up to 99 %) under visible light.…”

Kovalente organische Gerüstverbindungen: chemische Ansätze für Designerstrukturen und integrierte Funktionen

“…Durch Integrieren von vier verschiedenen Donor‐Akzeptor‐Einheiten werden asymmetrische CTFs (Abbildung a) mit ausgedehnter Absorption, erhöhter Energieübertragung und Ladungsträgermobilität erhalten. Diese CTFs katalysieren die Entstehung von Benzophospholoxid mit Ausbeuten bis zu 95 % und sind für vielfältige funktionelle Gruppen anwendbar . Das benzoxazolverknüpfte COF LZU‐190 (Abbildung b) ist sehr stabil bei Exposition gegenüber Sonnenlicht oder starken Säuren (9 m HCl) und Basen (9 m NaOH).…”