Cu–Ce Bimetallic Metal–Organic Framework-Derived, Oxygen Vacancy-Boosted Visible Light-Active Cu₂O–CeO₂/C Heterojunction: An Efficient Photocatalyst for the Sonogashira Coupling Reaction

Abstract

The development of an economical transition metalbased catalyst for photocatalytic carbon−carbon coupling reactions is aspiring. Herein, a Cu−Ce metal−organic framework (MOF) was synthesized and carbonized to produce bimetallic Cu 2 O−CeO 2 /C, which was utilized in the Sonogashira cross-coupling reaction. The defects and oxygen vacancies in the catalyst were characterized by Xray photoelectron spectroscopy and Raman spectroscopy, while the nature of Cu was characterized by H 2 -TPR analysis. The defectinduced MOF-derived Cu−Ce heterojunction created more oxygen vacancies (O V ) in CeO 2 , revealing the high photocatalytic activity. The Cu−Ce heterojunction (Cu 2 O−CeO 2 /C) formed a Cu(I)− phenylacetylide active complex and exhibited higher catalytic activity for the visible light-induced Sonogashira cross-coupling reaction. 25% Cu 2 O−CeO 2 /C offered 93.8% phenylacetylene conversion with a 94.2% Sonogashira product selectivity by using household light-emitting diodes. No discernible activity loss was observed from the recycling of the catalyst. Based on catalytic activity, control reactions, and physicochemical and optoelectronic characterization, the structure−activity relationship was established and a reaction mechanism was proposed. Replacement of the costly Pd metal-based catalyst with a cheap Cu 2 O−CeO 2 -based catalyst for the synthesis of commercially important compounds with a sustainable visible light-induced catalytic process will be highly attractive to chemists and industrialists.

Conjugated Cu-Ni bimetallic complex supported on Fe 3 O 4 @SiO 2 : An efficient nanocatalyst with synergistic performance for the solvent-free Sonogashira, and C-N cross-couplings

“…The synergetic interactions between active metal sites may be enhanced by an organic linker that bridges different metal centers and plays a sensitive charge transfer role 79 . In General, our observations and reported mechanisms suggest a plausible mechanism for the Fe3O4@SiO2@4-ABPT/Cu-Ni catalyzed Sonogashira cross-coupling reaction based on oxidative addition and reductive elimination steps 77,80,81 . However, it is not possible to recognize with certainty which metal carries out the reaction via oxidative addition and reductive elimination 77 .…”

Efficient photocatalytic performance and the mechanism of copper(i) metal–organic framework nanosheets

“…In the range of 150-550 mT, no signal about the existence of single electrons is captured, which indicates that there is no single electron in 1. Because Cu(I) has an extranuclear electron arrangement of 3d 10 , there are no isolated single electrons. XPS was used in order to further determine the element composition and the valence state of a copper ion in 1 (Fig.…”

“…Since 1972, photocatalytic oxidation technology has received widespread attention due to the ability of TiO 2 to decompose water into H 2 under light irradiation. [6][7][8] Subsequently, a large number of inorganic heterogeneous photocatalysts [9][10][11][12][13][14][15][16][17][18][19] (such as ZnO, Cu 2 O, and CdS) were developed for photocatalytic degradation of organic pollutants. However, inorganic semiconductor photocatalysts have the disadvantages of low light absorption efficiency and small specific surface area, which limit their widespread practical applications.…”

Photochemical Sonogashira coupling reactions: beyond traditional palladium–copper catalysis

“…Later in the same year, Srivastava et al , uncovered a sustainable and economical transition metal-based photocatalyst for the Sonogashira coupling with 94.2% product selectivity. 34 Herein, the author has designed and synthesized a bimetallic Cu 2 O–CeO 2 /C nanocomposite having a good light absorption ability and reactivity for the arylation of phenylacetylene with iodobenzene for 12 h along with a mild base with a household light emitting diode (Scheme 9). The characterization of Cu 2 O–CeO 2 /C suggests that the defect-induced Cu–Ce heterojunction created more oxygen vacancies facilitating the high photo catalytic activity.…”