Synthesis, Characterization, and Kinetic Study of Complexation of Vanadyl Acetylacetone with Some Unsymmetrical N3O Schiff Bases
摘要:
This article reports the synthesis and characterization of some new vanadyl Schiff base complexes, ((N-salicylidene-N'-pyrrolidene)-1,2-ethylenediaminato)oxovanadium(IV) [VO(Salpyren)], ((7-methyl-N-salicylidene-N'-pyrrolidene)-1,2-ethylenediaminato)oxovanadium(IV) [VO(Mesalpyren)], ((7-phenyl-N-salicylidene-N'-pyrrolidene)-1,2-ethylenediaminato)oxovanadium( IV) [VO(Phsalpyren)], ((N-salicylidene-N'-pyrrolidene)-1,3propylenediaminato)oxovanadium(IV) [VO(Salpyrpd)], ((7-methyl-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 Delta S not equal and the low values of Delta H not equal suggest an associative (A) mechanism.