Hydrothermal synthesis, crystal structure, spectroscopy, electrochemistry and antimycobacterial evaluation of the copper (II) ciprofloxacin complex: [Cu(cf)2(BF4)2]·6H2O

The hydrothermal reaction of ciprofloxacin (1) with Cu(BF4)2·6H2O yields a copper complex having a molecular formula, [Cu(cf)2(BF4)2]·6H2O (cf = ciprofloxacin), which is characterized by spectroscopic and electrochemical measurements as well as single crystal X-ray studies [a=9.1079(13), b=9.6112(16), c=11.4542(18) Å, α=90.518 (19)°, β=99.160 (18)°, γ=93.315 (19)°, P1bar, Z=1]. The F2O4 donor atom set forms a (4+2) distorted octahedral geometry around the central copper atom; which has a highly facile copper redox couple (+0.23 V). The copper conjugate exhibits a significant enhancement in the antitubercular activity probably arising out of its rapid intracellular reduction leading to oxygen activation, which is detrimental to the mycobacteria.