Cerium-Doped Manganese Oxide Catalyst for the Oxidative Coupling Synthesis of Fluorescent 2-Amino-1,9-dimethyl-3H-phenoxazin-3-one Using Atmospheric Oxygen

Abstract

The heterogeneous catalytic oxidative coupling synthesis of 2-amino-3H-phenoxazin-3-one (APXO) from the oxidative coupling of 2-aminophenol has important practical significance, due to its significant antiproliferative properties. However, the use of noble metals, alkaline additives, and explosive H 2 O 2 seriously restricts its applicability in industrial settings. Herein, through preparing a cerium-doped manganese oxide catalyst, we achieved the green synthesis of APXOs, using atmospheric oxygen as an oxidant, and without any additives. Its high activity can be attributed to the greatly enhanced oxidation capacity, oxygen activation capacity, and alkalinity that comes from doping with cerium. Remarkably, we found that 2-amino-1,9-dimethyl-3H-phenoxazin-3-one possesses excellent fluorescence properties and could be applied as a fluorescent molecular probe in various detection and labeling studies. This methodology provides an environmentally friendly and economical strategy for the synthesis of APXO in industrial applications, preserving the stability of the heterogeneous catalyst, which showed minimal metal leaching.

Highly efficient and stable hydrodechlorination of chlorophenols in a flow Pd–Ce/SiO2/Ni foam reactor

“…The excessive H 2 consumption at high temperatures could be attributed to the hydrogen spillover 15,45 and the surface oxygen reduction of ceria. 51,52…”

“…The excessive H 2 consumption at high temperatures could be attributed to the hydrogen spillover 15,45 and the surface oxygen reduction of ceria. 51,52 The Pd valence state in Pd-based Ni foam reactors was explored by XPS (Fig. 5(a)).…”

Modulating the Electronic Structure of α-Fe2O3 by Doping Atomically Dispersed Ce for the Transfer Hydrogenation of Nitroaromatics Using Stoichiometric Hydrazine Hydrate

“…Ce is also believed to have the ability to improve the distribution and concentration of the acidic site in metal oxide catalysts. 30 Building on the work of our group on Fe 2 O 3 -based 31,32 and CeO 2 -based 33,34 catalysts, atomically dispersed Ce-doped α-Fe 2 O 3 were synthesized through a simple co-precipitate method, which allowed the efficient reduction of aromatic nitro compounds using stoichiometric hydrazine hydrate at room temperature. A thorough characterization showed that the enhanced Lewis acidity of the host α-Fe 2 O 3 is a result of doping Ce atoms.…”

Ce4+/Ce3+ Redox Effect-Promoted CdS/CeO2 Heterojunction Photocatalyst for the Atom Economic Synthesis of Imines under Visible Light

“…Importantly, the VB and CB of CdS are 1.81 eV and −0.47 eV, respectively, 40 which are higher than those of CeO 2 (2.51 and −0.37 eV). 41,42 Inspired by these, and according to our research foundation in the thermocatalytic synthesis of imines 26,−28,43 and ceria-based (photo)catalyst, 44,45 we have successfully prepared cerium dioxide-modified cadmium sulfide photocatalysts in this work. Under visible light irradiation at room temperature, CdS/CeO 2 -200 °C enables atom-economic photocatalysis of the oxidative coupling of alcohols and amines to imines.…”