“…This hypothesis agrees with the 13 C CP-MAS spectrum of complex 3, which is very similar to the spectrum of 1 and 2 in the 160-180 ppm region, showing two signals that are assigned to the carbon atoms directly bonded to the oxygen atoms linked to rhenium. 22 The IR spectra also agrees with the proposed coordination for ciprofloxacin, showing two intense signals at 1614 and 1480 cm -1 , in concordance with the observed values for complexes 1-2, and with reported data for other complexes with this coordination. 19,29,54 No signal was observed at 1730 cm -1 , showing that this complex is free of contamination with ciprofloxacin and two intense peaks, assigned to the characteristic υ(CO) absorptions of the fac-{Re(CO) 3 } fragment,…”