Jakovljevic, Ivan Petrovic, Djordje Joksovic, Ljubinka Lazarevic, Ivan Jelikic-Stankov, Milena Djurdjevic, Predrag Complex formation equilibria between aluminum(III), gadolinium(III) and yttrium(III) ions and some fluoroquinolone ligands. Potentiometric and spectroscopic study <div><p>Complex formation equilibria of aluminum(III), gadolinium(III), and yttrium(III) ions with the fluoroquinolone antibacterials moxifloxacin, ofloxacin, fleroxacin, lomefloxacin, levofloxacin, and ciprofloxacin were studied in aqueous solution by potentiometric and spectroscopic methods. The identity and stability of metal–fluoroquinolone complexes were determined by analyzing potentiometric titration curves (310 K, <i>μ</i> = 0.15 M NaCl, pH range = 2–11, <i>C</i><sub>L</sub>/<i>C</i><sub>M</sub> = 1 : 1 to 3 : 1, <i>C</i><sub>M</sub> = 1.0 mM) with the aid of Hyperquad2006 program. The main species formed in the system may be formulated as M<sub>p</sub>H<sub>q</sub>L<sub>r</sub> (p = 1, q = −2 to 2, r = 1–3, L = fluoroquinolone anion, logarithm of overall stability constant, log <i>β</i><sub>p,q,r</sub> = in the range <i>ca.</i> −10 to 45). The stability of complexes is mostly influenced by metal ion properties (ionization potential, ionic radius) indicating partial ionic character of the coordination bond. The complexes were also characterized by spectroscopic measurements: spectrofluorimetry, <sup>1</sup>H-NMR, and ESI-MS. Fluorimetric data were evaluated with the aid of HypSpec2014 and indicated the formation of ML<sub>r</sub> (r = 1–3) complexes with cumulative conditional stability constants significantly lower than the thermodynamic ones. NMR and MS data corroborate potentiometrically determined speciation. Calculated plasma mobilizing capacity of the ligands generally follows the order levofloxacin > moxifloxacin > ciprofloxacin at concentration levels of the ligands higher or equal to <i>ca.</i> 10<sup>−4</sup> M.</p></div> gadolinium;potentiometric;spectroscopic measurements;Complex formation equilibria;concentration levels;spectroscopic study Complex formation equilibria;fluoroquinolone antibacterials moxifloxacin;stability constants;MS data;yttrium;Hyperquad 2006 program;coordination bond;cm;cl;nmr;spectroscopic methods;aid;metal ion properties;HypSpec 2014;Fluorimetric data;fluoroquinolone ligands;levofloxacin;complex 2015-11-26
    https://tandf.figshare.com/articles/journal_contribution/Complex_formation_equilibria_between_aluminum_III_gadolinium_III_and_yttrium_III_ions_and_some_fluoroquinolone_ligands_Potentiometric_and_spectroscopic_study/1568467
10.6084/m9.figshare.1568467.v4