Using novel open-framework copper borovanadate as an effective catalyst in the conversion of cyclohexanol to cyclohexanone

• Published in: Journal of molecular structure 2025-02, Vol.1322, p.140449, Article 140449
• Main Authors: Feng, Yuquan, Zhong, Zhiguo, Chen, Shuyang, Meng, Zhaohui, Liu, Kecheng
• Format: Article
• Language: English
• Subjects: Catalytic mechanism; Copper borovanadate; Open-framework; Optical property; Selective oxidation
• ISSN: 0022-2860
• DOI: 10.1016/j.molstruc.2024.140449

•A novel open-framework copper borovanadate was synthesized.•The stable pH range of the borovanadate anion in DMF solution was explored.•It was firstly applied to the selective oxidation of cyclohexanol to cyclohexanone.•The compound exhibited stable and effective catalytic activity. A new open-framework copper borovanadate containing two oxidation states of V4+ and V5+ cations {[Cu5(1,2-dap)10][VV2VIV10B18O54(OH)6(H2O)]}·2H3BO3·9H2O (1,2-dap: 1, 2-propylene diamine) (1) using 1,2-dap as template agent has been successfully prepared. It is composed of five coordination cations [Cu(1,2-dap)2]2+and one borovanadate anion [VV2VIV10B18O54(OH)6(H2O)]10- constructed by one {B18O30(OH)6} and two {V6O18} subunits, as well as two isolated H3BO3 molecules and nine H2O molecules. The compound exhibits for the first time penta-coordinated copper cations, uncoordinated H3BO3 molecules and 1, 2-dap ligands in the series of open-framework borovanadates. Its UV diffuse-reflectance spectrum, Mott-Schottky curve, fluorescent emission, chromaticity and second-order lifetime were investigated in detail. The stable pH range (5.8–2.3) of the borovanadate anion in DMF solution was explored by means of fluorescence and UV spectra. In particular, it showed effective catalytic activity in the conversion of cyclohexanol to cyclohexanone (conversion: 86.8 %, selectivity: 97.4 %). The possible catalytic mechanism for the catalytic reaction had been also established. The studies revealed that the borovanadate could be used as a potential stable catalyst for the selective oxidation of cyclohexanol. [Display omitted]