A mild and effective photo-catalytic protocol for triggering inert nitrous oxide to participate in oxidative dehydrogenation of alcohols under visible light illumination

The development of a mild and efficient activation protocol for the nitrous oxide (N2O)-based selective oxidation has very important academic and applied values in the harmless treatment and high value-added utilization of N2O. This paper discloses that decatungstate (DT) anion and especially its hybrids with metal ions (1%M-DTs) are active for the N2O-involved oxidative dehydrogenation (ODH) of cyclohexanol in MeCN under visible light illumination. The best 1%Cu-DT achieves ca. 46.3% cyclohexanone yield and its turnover frequency (TOF) is up to 6.56 h(-1) at high substrate concentration (1 M). Also, 1%Cu-DT is efficient for the N2O-involved ODH reactions of aliphatic and especially aromatic primary/secondary alcohols. UV-vis spectra, the isotope tracing tests of (H2O)-O-18 and DFT calculations support that the double-reduced H2DT species in situ-generated during the photo -reaction may turn into its oxygen-vacant state through dehydration, which the latter plays a crucial role in the oxygen transfer from N2O to it.

Automated summary

The development of a mild and efficient activation protocol for N2O-based selective oxidation has significant academic and applied values. This study reveals that decatungstate (DT) anion and its hybrids with metal ions are active for the N2O-involved oxidative dehydrogenation reactions. The best catalyst achieves high cyclohexanone yield and is efficient for the N2O-involved ODH reactions of various alcohols.