Table of Contents
Metal-Based Drugs
Volume 6, Issue 1, Pages 1-4

NMR Investigation of the Copper(II)-Ciprofloxacin System

1University of Ljubljana, Faculty of Chemistry and Chemical Technology, Ašsskerčeva 5, Ljubljana 1000, Slovenia
2Department of Chemistry, University of Bergen, Allegt. 41, Bergen N-5007, Norway

Received 4 November 1998; Accepted 3 December 1998

Copyright © 1999 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


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)2]Cl2.6H2O isolated from the slightly acidic solution. There are additional significant changes in T1 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.