Metalloantitubercular compounds Part 3: Synthesis, crystal structure, spectroscopy, electrochemistry and antimycobacterial activity of the copper(II) ciproploxacin (cfH) complex and its phenanthroline adduct

Abstract

The X-ray crystal structures of two ciprofloxacin compounds, viz. [Cu(cfH) 2 (Cl) 2 ] Á 2MeOH Á 6H 2 O (2) and [Cu(cfH)(phen)Cl]BF 4 Á 4H 2 O (3) are reported. Complex (2) has a distorted octahedral geometry, whereas for the nitrogen adduct (3) a distorted square-pyramidal geometry is seen. Significant enhancement in the antimycobacterial activity of the copper conjugates correlates with their copper redox couples (Cu 2+ /Cu + ) probably due to its relevance to intracellular accumulations and subsequent role in generating oxidative stress.

A copper(II) complex of 1,10-phenanthroline and enrofloxacin

“…It adopts a slightly distorted square-pyramidal geometry [trigonality index (Addison et al, 1984) An arrangement similar to that of (I) has been observed in [Cu(erx)(phen)Cl] (Efthimiadou et al, 2006), where the enrofloxacin and the phenanthroline occupy the four positions in the basal plane, while the apical position is occupied by a Clion. Metal-to-ligand distances in (I) are also similar to those found in related compounds with cinoxacin [1- (Saha et al, 2005;Drevenšek et al, 2003) all of them presenting small trigonality indexes.…”

“…A similar arrangement to that of the title compound has been observed in [Cu(erx)(phen)Cl] (Efthimiadou et al, 2006), where erx and phen occupy the four positions in the basal plane, while the Cl atom is in the apical position. Metal-toligand distances are also similar to those found in related compounds with cinoxacin (Mendoza-Díaz et al, 1987) and ciprofloxacin (Saha et al, 2005;Drevenšek et al, 2003). A trigonality index may by computed for Cu II (Addison et al, 1984).…”