Synthesis, characterization and crystal structures of new bidentate Schiff base ligand and its vanadium(IV) complex: The catalytic activity of vanadyl complex in epoxidation of alkenes

Gholamhossein Grivani, Aliakbar Dehno Khalaji, Vida Tahmasebi, Kazuma Gotoh, Hiroyuki Ishida

Research output: Contribution to journalArticle

54 Citations (Scopus)

Abstract

The Schiff base ligand N-salicylidin-2-bromoethylimine (L) and its vanadium(IV) complex, VOL2 (1), were synthesized and characterized by using X-ray, CHN, 1H NMR and FT-IR methods. X-ray analysis shows the Schiff base ligand L acts as a bidentate (O, N) chelating ligand and coordinates via imine nitrogen and phenolato oxygen atoms to the V(IV) center. The coordination geometry around the V(IV) center in 1 is approximately square pyramidal, as indicated by the unequal metal-ligand bond distances and angles, with the basal plane formed by the N2O2 donors of the two bidentate Schiff base ligands, the two phenolato O atoms and the two imine N atoms are in the trans position. The coordination sphere of the V(IV) is completed by one oxygen atom in apical position. In the Schiff base ligand, L, there are some classical intramolecular O1-H1⋯N1 and non-classical intermolecular C9-H9b⋯O1 hydrogen bonds, while in 1, there are two non-classical intermolecular C7-H7⋯O3 and C8-H8b⋯O3 hydrogen bonds. The catalytic activity of 1 in epoxidation of cyclooctene was investigated in different conditions to obtain optimum conditions. The effects of solvent, oxidant, catalyst concentration and alkene/oxidant ratio were studied and the results showed that in CCl4 in the presence of tert-butylhydroperoxide in 1:3 alkene/oxidant ratio, high epoxide yield was obtained. The epoxidation of alkenes was also carried out in optimized conditions that high catalytic activity and selectivity were obtained.

Original languageEnglish
Pages (from-to)265-271
Number of pages7
JournalPolyhedron
Volume31
Issue number1
DOIs
Publication statusPublished - Jan 4 2012

Keywords

  • Epoxidation
  • Non classical hydrogen bond
  • Schiff base
  • Vanadium(IV) complex

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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