An Important Photocatalysis Oxidation: Selective Oxidation of Aniline to Azobenzene over a {P4Mo6}-based Crystalline Catalyst Under Visible-light Irradiation at Room Temperature

Selective oxidation of aniline toazobenzene with a highereconomicvalue is significant for modern industrial production. However, thehigh reaction temperature and undefined catalytic reaction centeralways limit the promotion of this reaction. Here, we designed andsynthesized a new [P4MoV O-6(31)](12-)-based cobalt-containing complex (Hbiz)(5){Co(H2O)(3)[Co(H2O)(2)](2)}{Co[Mo6O12(OH)(3)(PO4)(HPO4)(3)][Mo6O12(OH)(3)(PO4)(2)(HPO4)(2)]}& BULL;3H(2)O (1; biz = benzimidazole)under solvothermal conditions. Using 1 as the photocatalyst,the visible-light-driven conversion of aniline to azobenzene at roomtemperature was realized for the first time (conversion rate 97%,selectivity 96% of azobenzene, reaction time of 12 h). Additionally,real sunlight irradiation can produce a comparable outcome in 48 h.The mechanism investigation manifested that the Mo and Co centersin 1 acted as Bro''nsted and Lewis acid centers,synergistically promoting the aniline oxidation reaction. This researchadvances the application of polyoxometalate-based photocatalysts whilealso offering a sustainable and effective method for producing azobenzene. A new {P4Mo6}-based crystallinephotocatalystwas successfully synthesized for the efficient selective oxidationof aniline to azobenzene under visible light at room temperature.

Automated summary

A new [P4MoV O-6(31)](12-)-based cobalt-containing complex was synthesized for the visible-light-driven conversion of aniline to azobenzene. The conversion rate was 97% with a selectivity of 96% of azobenzene, and the reaction could be achieved at room temperature.