Research Project: Görünür Işık Aydınlanması Altında Heteroarenlerin C-II Arilasyonunu Gerçekleştirebilecek Siyah Fosfor Temelli Heteroeklem Yapılı Fotoredoks Katalizörlerinin Tasarımı ve Sentezi
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Contributors
Funders
ID
TB.00540
Authors
Metin, Önder
Faculty Member
Publications
Synergism between few-layer black phosphorus and graphitic carbon nitride enhances the photoredox C-H arylation under visible light irradiation
(Royal Society of Chemistry, 2022) Eroğlu, Zafer; Kubanaliev, Temirlan; Metin, Önder; Özer, Melek Sermin; Kılıç, Haydar; Department of Chemistry; KUTEM (Koç University Tüpraş Energy Center); KUYTAM (Koç University Surface Science and Technology Center); Yes; College of Sciences; Research Center
The development of solar-driven chemical transformations is one of the most attractive research interests as they lay the groundwork for a more sustainable future. To reach this target, efficient photocatalysts, particularly metal-free photocatalysts, should be designed and fabricated. For the design of efficient photocatalysts in terms of optical, chemical/thermal properties, and long-term stability, constructing heterojunctions of two-dimensional (2D) materials consisting of earth-abundant elements is one of the most environmentally friendly options. In this study, a highly efficient photoredox catalyst was developed by combining few-layer black phosphorus (FLBP) and graphitic carbon nitride (g-CN) binary heterojunctions, which build up a synergistic effect at the heterojunction interfaces. As-prepared FLBP/g-CN heterojunctions were tested in photoredox C-H arylation of heteroarenes with diazonium salts under visible light irradiation and showed excellent activity, with the product yields reaching up to 94% under ambient conditions. The activity of FLBP/g-CN heterojunctions showed a volcano-shaped relation with respect to the BP loading ratios, where the FLBP/g-CN with 35 wt% FLBP provided the best performance. The substrate scope of FLBP/g-CN heterojunctions was investigated over a variety of heteroarenes (furan, thiophene, and N-Boc pyrrole) with diazonium salts bearing electron-donating (ED) and electron-withdrawing (EWD) groups (29 examples in total). Moreover, a suitable band diagram showing a unique electron-hole migration between g-CN and FLBP, which is different from anticipated type-I heterojunction in the heterojunction structure, was proposed by the mechanistic studies and charge migration experiments.
Reduced graphene oxide/few-layer phosphorene binary heterojunctions as metal-free photocatalysts for the sustainable photoredox C-H arylation of heteroarenes
(American Chemical Society, 2024) Alemdar, Sıla; Eroğlu, Zafer; Kubanaliev, Temirlan; Metin, Önder; Turbedaroglu, Özge; Kılıç, Haydar; Department of Chemistry; KUYTAM (Koç University Surface Science and Technology Center); Yes; College of Sciences; Research Center
Herein, we report the fabrication of few-layer phosphorene (FLP)/reduced graphene oxide (rGO) binary heterojunctions as metal-free photocatalysts for the direct C-H arylation of heteroarenes under visible light irradiation. The FLP/rGO heterojunctions were prepared by mixing the solutions of well-exfoliated rGO and FLP nanosheets in an ultrasonic bath, resulting in a well-coupled structure between rGO and FLP. Characterization revealed enhanced stability, charge separation efficiency, and extended charge transfer ability in the heterojunction compared to the pristine materials. Studying different FLP to rGO mass ratios helped to find the optimum synergy where the materials exhibited the highest photocatalytic activity, and the optimized FLP/rGO catalyst with 30% FLP yielded the desired products with the highest photocatalytic efficiency in the C-H arylation of aryl diazonium salts and heteroarenes (24 examples in total). Notably, aryl diazonium salts with electron-withdrawing groups achieved high yields in the range of 68-90%. The FLP/rGO heterojunctions were successfully applied in synthesizing dantrolene, a commercially available drug, yielding 41% yield for C-H arylation and 90% yield for subsequent synthesis. The heterojunctions demonstrated excellent reusability, maintaining high catalytic activity over five cycles with only a 6% decrease in their initial activity. Mechanistic studies suggest a plausible single electron transfer mechanism wherein photogenerated electrons are transferred from FLP/rGO to aryl diazonium salts, forming biaryl radical intermediates and subsequent products. Overall, the FLP/rGO binary heterojunctions have been demonstrated to be efficient and sustainable metal-free photocatalysts for C-H arylation reactions, showcasing a broad substrate scope and potential applications in synthetic chemistry and pharmaceutical synthesis.
