Synthesis, thermal, spectral, antimicrobial and cytotoxicity profile of the Schiff bases bearing pyrazolone moiety and their Cu(II) complexes

A series of Schiff bases resulted in the [1 + 1] condensation of 8-alkyl-2-hydroxy-tricyclo[7.3.1.02.7]-tridecan-13-one with the 4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one, and their complexes CuL(CH3COO)2·nH2O were synthesized. The compounds were characterized by microanalytical, ESI–MS, NMR, IR, electronic and EPR spectra. Based on the ESI–MS and IR spectra, a mononuclear structure with both Schiff base and acetate as chelate was proposed for complexes. An elongated rhombic stereochemistry was assigned considering electronic and EPR data. The thermal analyses have evidenced processes as water elimination, acetate decomposition as well as oxidative degradation of the Schiff base moiety. The bioevaluation of compounds in relation to planktonic and biofilm-embedded microbial cells, as well as to human cells, indicates an improved activity of complexes over ligands. The same tendency was observed for antioxidant activity.