Evaluation of the anti-inflammatory and analgesic effects of Cu(II) and Zn(II) complexes derived from 2-(naphthalen-1-yloxy)-N′-(1-(pyridin-2-1)ethylidene) acetohydrazide

•Preparation of complexes of 2-(naphthalen-1-yloxy)-N′-(1-(pyridin-2-yl)ethylidene) acetohydrazide (HA2PNA) with Zn and Cu acetate.•Characterization of all compounds by elemental and spectral techniques.•Anti-inflammatory and analgesic activity in rat model of collagen adjuvant arthritis and compared with piroxicam.

New Cu(II) and Zn(II) complexes of 2-(naphthalen-1-yloxy)-N′-(1-(pyridin-2-yl)ethylidene) acetohydrazide (HA2PNA) have been prepared and characterized by elemental analyses, spectral (IR, UV–visible, ESR and 1H NMR) as well as magnetic and thermal measurements. According to the data, the complexes assigned the formulae: [Cu(A2PNA)2]H2O and [Zn(A2PNA)(OAc)(H2O)], respectively. IR data revealed that the ligand acts as before ONN and after morever ONN mononegative tridentate via deprotonated carbonyl oxygen (CO) and both (CN)imine and (CN)pyridine nitrogen atoms. The bond lengths, bond angles, HOMO, LUMO, dipole moment and charges on the atoms have been calculated by using density functional theory (DFT) at B3LYP level with 6-31G and 6-31G(d,p) basis sets to confirm the geometry of the ligand and the investigated complexes. Also, the kinetic parameters were determined for each thermal degradation stage of the complexes using Coats–Redfern and Horowitz–Metzger methods. Moreover, the complexes have been tested for anti-inflammatory and analgesic activity in rat model of collagen adjuvant arthritis and compared with piroxicam. All the compounds showed a significant anti-inflammatory and analgesic effect versus piroxicam.

Graphical abstractMolecular structure of [Cu(A2PNA)2]H2O.Figure optionsDownload full-size imageDownload as PowerPoint slide