New oxidovanadium( iv ) complex with a BIAN ligand: synthesis, structure, redox properties and catalytic activity

• Published in: New journal of chemistry Vol. 42; no. 19; pp. 16200 - 16210
• Main Authors: Fomenko, Iakov S., Gushchin, Artem L., Shul’pina, Lidia S., Ikonnikov, Nikolay S., Abramov, Pavel A., Romashev, Nikolay F., Poryvaev, Artem S., Sheveleva, Alena M., Bogomyakov, Artem S., Shmelev, Nikita Y., Fedin, Matvey V., Shul’pin, Georgiy B., Sokolov, Maxim N.
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 2018
• Subjects: Alkanes; Catalysis; Catalytic activity; Chemical synthesis; Coordination compounds; Crystal structure; Crystallography; Dichloromethane; Hydrogen peroxide; Infrared radiation; Magnetic properties; Oxidation; Oxygenation; Reaction kinetics; Reduction; Silver chloride; Toluene; X-ray diffraction
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/C8NJ03358G

Reaction of VCl 3 with bis[ N -(2,6-diisopropylphenyl)imino]acenaphthene (dpp-bian) in air afforded [VOCl 2 (dpp-bian)] ( 1 ). The complex was characterized by IR and UV-vis spectroscopies and elemental analysis. The crystal structure of 1 was determined by X-ray diffraction (XRD) analysis. The vanadium atom is in a square-pyramidal OCl 2 N 4 coordination environment. The cyclic voltammogram (CV) in dichloromethane reveals an irreversible oxidation process at +1.40 V ( vs. Ag/AgCl) assigned to the V( iv )/V( v ) couple, and two consecutive quasi-reversible one-electron reduction processes at −0.32 V and −1.05 V ( vs. Ag/AgCl), respectively, assigned to the bian/bian −/ ˙ and bian −/ ˙/bian 2− couples, followed by irreversible reduction at −1.6 V ( vs. Ag/AgCl). The EPR spectrum of 1 in toluene shows a single 8-line signal typical for oxidovanadium( iv ) complexes with d 1 configuration. The magnetic behavior of 1 confirms the presence of one unpaired electron ( μ eff (330 K) = 1.67 μ B ), and the isolation of the paramagnetic centers. Application of 1 to oxidation of alkanes documented high catalytic activity under mild conditions. The kinetics and selectivity of alkane oxygenation by the 1 /H 2 O 2 and 1 /PCA/H 2 O 2 systems (PCA is pyrazine-2-carboxylic acid) were studied. The reaction is more efficient in the presence of PCA.