A self-assembly solvothermal synthesis of SiMoVn@[Cu6O(TZI)3(H2O)6]4·nH2O for the efficient selective oxidation of various alkylbenzenes

Abstract

The selective oxidation of alkylbenzenes contributes greatly to the production of high-value chemicals. However, developing novel and efficient catalysts remains a great challenge. To explore new and efficient catalysts, a series of POMs of H_(4+n)SiMo_(12−n)V_nO₄₀ (SiMoV_n, n = 1, 2 and 3) were reacted with rht-MOF-1 ([Cu₆O(TZI)₃(H₂O)₆]₄·nH₂O) by a one-pot self-assembly solvothermal method. As a result, three SiMoV_n@rht-MOF-1 (1, n = 1; 2, n = 2 and 3, n = 3) were isolated. Single crystal analysis revealed that SiMoV_n were successfully introduced in the cages of rht-MOF-1. When complex 3 was employed as a catalyst, it effectively catalyzed the selective oxidation of alkylbenzene with a conversion of 99% and selectivity of 99% under optimized reaction conditions. Recycling experiments proved that complex 3 is stable and recyclable after six cycles. In comparison with analogous catalysts, complex 3 exhibits outstanding catalytic performance. Furthermore, the kinetics and reaction mechanism were investigated and verified by EPR and XPS analysis. This approach paves a facile route to prepare POMs@MOFs for the selective oxidation of various alkylbenzenes.