摘要
Two novel isopolyoxovanadates modified by ethylenediamine,[Cu(en)_(2)]_(2)[V_(4)^(Ⅳ)V_(6)^(Ⅴ)O_(25)](1)and[Cu(en)_(2)][V_(6)^(Ⅴ)O_(16)](2)(en=ethanediamine,C_(2)H_(8)N_(2)),have been successfully synthesized under hydrothermal conditions.Both compounds represent new structural types in the V_(10)and V_(6)cluster family,featuring two-dimensional pure inorganic vanadate layer structures.The compounds were thoroughly characterized by infrared spectroscopy(IR),single-crystal X-ray diffraction(SCXRD),powder X-ray diffraction(PXRD),X-ray photoelectron spectroscopy(XPS),and thermogravimetric analysis(TG).Their catalytic properties were investigated in sulfide oxidation and Knoevenagel condensation under mild conditions.Notably,compound 1,which contains mixed-valent V^(Ⅳ)/V^(Ⅴ)centers,demonstrates exceptional catalytic performance in the selective oxidation of methyl phenyl sulfide.It achieves a conversion rate of 98.3% with a selectivity of 84.9% towards sulfoxide within just 30 minutes at room temperature.Moreover,in the Knoevenagel condensation,compound 1 demonstrates remarkable activity with 95.2% conversion of benzaldehyde and>99% product selectivity within 90 minutes.Recycling experiments confirm the excellent stability of both compounds.This study not only enhances the structural diversity of polyoxovanadates but also offers efficient bifunctional catalysts for organic transformations under mild conditions.
基金
supported by the Natural Science Foundation of Hebei Province(Grant No.B2021205027,B2021205024 and B2020205006)
the Science Foundation of Hebei Normal University(L2025K02).
