Synthesis, characterization, and biological evaluation of new copper complexes of naphthyl pyrazole ligands

Abstract

Two naphthalene pyrazole ligands were synthesized using KOH/DMSO and Cu catalyst and characterized with FT-IR, ESIMS, $^{1} H, and ^{13}C NMR$ spectroscopies. The crystal structures of 1-(2-methylnaphthalen-1-yl)-1H-pyrazole (MeNap-Pz) ligand have been determined with X-ray crystal structure analysis. Reaction of the ligands with $Cu(NO_3 )_2 x3.5H_2O$ gave two new complexes and characterized with magnetic susceptibility, molar conductance, FT-IR, LCMS-MS, ICP-OES, NMR, thermogravimetric analysis, and ESR spectra. The spectral data of the ligands are coordinated to the metal ion through the nitrogen atoms of the pyrazole ring. Consequently, it has been determined that [Cu(MeNap-$Pz)^2 (NO^3 )]NO^3 .2H^2O$ complex showed square planar geometry and [Cu(NapMe-$Pz)2 (NO3 )2 ]. H2O$ complex showed octahedral geometry. All compounds were screened for in vitro antibacterial activity and copper complexes have been shown to be effective on bacteria.