Visible Light-Emitting Diode Light-Driven Cu_0.9Fe_0.1@RCAC-Catalyzed Highly Selective Aerobic Oxidation of Alcohols and Oxidative Azo-Coupling of Anilines: Tandem One Pot Oxidation–Condensation to Imidazoles and Imines

Abstract

Here, we have demonstrated visible light-emitting diode light-driven selective and efficient aerobic oxidation of primary/secondary alcohols to aldehydes/ketones and oxidative azo-coupling of anilines using biomass rice husk-derived chemically activated carbon sheet-supported copper–iron bimetallic hybrid nanomaterials (CuxFe1–x@RCAC) under oxidant and additive-free conditions. The catalytic activity of the CuxFe1–x@RCAC materials has been investigated for the oxidation of alcohols and anilines, and Cu0.9Fe0.1@RCAC was established as the best catalyst. Moreover, a tandem one-pot protocol has been developed for the sequential oxidation of alcohols followed by condensation to functionalized imidazole and imine derivatives in high isolated yields. The hybrid materials were highly robust and stable under the reaction conditions and were recovered simply by filtration and recycled up to 12th run without considerable loss in catalytic activity.

Direct Oxidative Azo Coupling of Anilines Using a Self-Assembled Flower-like CuCo2O4 Material as a Catalyst under Aerobic Conditions

“…In continuation of our previous research on developing sustainable organic transformations using heterogeneous nanocatalysts, , we have previously synthesized Cu 2 O–RuO 2 and Cu 0.9 Fe 0.1 @RCAC materials for the oxidative azo coupling of anilines . In this paper, we report the synthesis of self-assembled flower-like CuCo 2 O 4 and its remarkable catalytic efficiency in the direct oxidative azo coupling of anilines (Scheme ).…”

Zinc Indium Sulfide‐Based Photocatalysts for Selective Organic Transformations

“…[103] The synthesis of imines via the oxidative coupling of amines through photocatalysis is gaining attention because of its high atomic economy and environmentally benign nature, presenting a safer alternative to traditional synthetic routes. [104] Table 4 presents a collection of studies detailing the use of ZnIn 2 S 4 -based materials in the oxidative coupling of amines to synthesize imines. In the context of these photocatalytic processes, there are generally two mechanistic pathways proposed for the selective oxidation of amines.…”

“…Imines are an important class of nitrogen‐containing intermediates that find applications in a variety of sectors, including anti‐corrosion treatments, liquid crystal polymers, pharmaceuticals, and oil field technologies [103] . The synthesis of imines via the oxidative coupling of amines through photocatalysis is gaining attention because of its high atomic economy and environmentally benign nature, presenting a safer alternative to traditional synthetic routes [104] . Table 4 presents a collection of studies detailing the use of ZnIn 2 S 4 ‐based materials in the oxidative coupling of amines to synthesize imines.…”

Recent Advances in Aerobic Photo‐Oxidation of Methanol to Valuable Chemicals

“…Reactions 2 and 3: The process of molecular adsorption of methanol on the oxidized TiO 2 surface by the formation of a hydrogen bond or with a bridging oxygen anion ( ), [97,109] respectively. Reactions 4 and 5: the extraction of a proton from the methanol hydroxyl group and production of a methoxy species.…”