Spectral characterization and anti-inflammatory activity of Schiff-base complexes derived from leucine and 2-acetylpyridine

Abstract

Schiff-base complexes [ML·nH2OAc]mH2O (where L = Schiff base derived from condensation of 2-acetylpyridine and leucine; M = Cu(II), Ni(II) or Co(II); n = 0–2 and m = 3/2–2) and [ZnLOH]H2O have been synthesized and characterized using elemental analyses, spectral analyses (UV-Vis, IR, 1H NMR), conductance, thermal analyses, magnetic moments and QSAR analyses. The results showed that the ligand is mononegative tridentate coordinating the metal through pyridyl nitrogen, azomethine nitrogen, and carboxylate oxygen after deprotonation of the hydroxyl. Cu(II) forms square-planar and Ni(II) and Zn(II) form tetrahedral complexes, while Co(II) is octahedral. Prediction from quantitative structure activity relationship (QSAR) for anti-inflammatory activity in rats (% edema inhibition) has been made. The copper complex showed a significant analgesic and antirheumatic effect.