NMR Investigation of the Copper(II)‐Ciprofloxacin System

Abstract

A proton NMR study was performed on the copper(ll)-ciprofloxacin system. The proton relaxation times (T1) were determined from the titration data in acidic and basic media. In acidic medium the H5 signal is dramatically affected and it is assumed that copper is bonded to the quinolone through carbonyl and one of the carboxyl oxygens. Such bonding is in agreement with the X-ray literature data for the complex [Cu(cf)1]Cl2.6H2O isolated from the slightly acidic solution. There are additional significant changes in 1T1 of H3′ and H5′ atoms which suggest that the terminal nitrogen atom of the piperazine ring system-N4′ also interacts with copper in the basic conditions. Thus it is plausible that more than one species are present in the solution at high pH values.

X-Ray crystallographic, NMR and antimicrobial activity studies of magnesium complexes of fluoroquinolones – racemic ofloxacin and its S-form, levofloxacin

“…4, Tables S1 and S2 in Supplementary Material). This is also in agreement with Cu(II) titration data of fluoroquinolones [39]. Assuming that the Mn(II) and Mg(II) positions are about equal the difference in line broadening between H2 and H5 agrees qualitatively with the averaged calculated distances in the two crystal structures (Mg(II)-H2 = 5.2 Å ; Mg(II)-H5 = 4.3 Å ).…”

Schiff base method characterization of the newly synthesized Modified Levofloxacin Complex (MOLVX) and its activity against the HRT-18 cell line isolated from a male patient with colorectal adenocarcinoma

“…Protons far from levofloxacin binding sites leave their signals virtually untouched. The spectrum also showed another signal in the aromatic region related exactly at (7.98 ppm) and (7.14 ppm) assigned to aromatic protons of the 1,10-phenanthroline molecule (Hosseini et al, 2013;Sultana et al, 2013;Turel et al, 1999). (Roy & Roy, 2017).…”