Synthesis, Characterization, and Kinetic Study of Complexation of Vanadyl Acetylacetone with Some Unsymmetrical N₃O Schiff Bases

Abstract

This article reports the synthesis and characterization of some new vanadyl Schiff base complexes, ((N-salicylideneN′-pyrrolidene)-1,2-ethylenediaminato)oxovanadium(IV) [VO (Salpyren)], ((7-methyl-N-salicylidene-N′-pyrrolidene)-1,2-ethylenediaminato) oxovanadium(IV) [VO(Mesalpyren)], ((7-phenylN-salicylidene-N′-pyrrolidene)-1,2-ethylenediaminato) oxovanadium(IV) [VO(Phsalpyren)], ((N-salicylidene-N′-pyrrolidene)-1,3propylenediaminato)oxovanadium(IV) [VO(Salpyrpd)], ((7methyl-N-salicylidene-N′-pyrrolidene)-1,3-propylenediaminato) oxovanadium(IV) [VO(Mesalpyrpd)], ((7-phenyl-N-salicylidene-N′-pyrrolidene)-1,3-propylenediaminato)oxovanadium(IV) [VO (Phsalpyrpd)]. These complexes were characterized by elemental analyses, IR, UV-Vis, and mass spectra. The kinetics and mechanism of the complex formation in methanol were studied spectrophotometrically. The second order k2 rate constants show the following trend: Mesalpyren > Salpyren > Phsalpyren > Mesalpyrpd > Salpyrpd > Phsalpyrpd The linear plots of kobs vs. the molar concentration of VO(acac)2, the large negative values of Δ S ≠ and the low values of Δ H ≠ suggest an associative (A) mechanism.

Keywords:

• kinetic
• mechanism
• Schiff base
• synthesis
• Vanadium complex

The author is grateful to Shiraz University Research Council for its financial support.