Photoinduced one-pot synthesis of hydroxamic acids from aldehydes through in-situ generated silver nanoclusters
Hydroxamic acids have attracted significant attention due to their widespread use in applied chemistry. In this report, a modified Angeli–Rimini method has been achieved via the visible light-mediated catalytic transformation of a variety of heterocyclic, aromatic and aliphatic aldehydes 1a–j to their corresponding hydroxamic acids 2a–j in 81–93% yield. The unique ability of vitamin K3 as a photoredox catalyst to expedite the development of completely new reaction mechanisms and to enable the construction of challenging carbon–nitrogen bonds has been investigated. It is shown for the first time that the vitamin K3 and aldehyde are largely responsible for rapid in situ reduction of Ag+ ions to catalytic photoluminescent Ag nanoclusters that possess a bandgap energy of 2.87 eV and are less than 2 nm in size. A mechanism for this reaction has been proposed and is supported by UV–Vis, TEM, ESI/MS, FT-IR, 1H NMR and 13C NMR analyses. The investigated method utilizes readily available reagents and produces the hydroxamic acids in high yields without the formation of side products, making it simple, practical and cost-effective.
KeywordsAg nanoclusters Angeli–Rimini reaction Hydroxamic acids Vitamin K3 Photocatalysis
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The authors are grateful to the National Research Center (Egypt), National Institute of Laser Enhanced Sciences, Cairo University (Egypt) and NORD University (Norway) for providing the facilities.
Compliance with ethical standards
Conflict of interest
The authors have declared no conflict of interest.
- 4.S.L. Yedage, B.M. Bhanage, Synthesis 47, 526 (2015)Google Scholar