Complexes of Co(II) and Zn(II) with ofloxacin. Crystal structure of [Co(oflo)2(MeOH)2].4MeOH.

Ofloxacin (oflo) is able to interact with Co(II) and Zn(II) salts to form complexes with the general formula [M(oflo)(2)]. 4H(2)O, (M = Co, Zn). Bonding takes place through one of the oxygen atoms of the carboxylate group (acting as a monodentate) and the oxygen atom of the ketonic group. The IR bands of the carboxylic and ketonic group at 1713 and 1622 cm(-1), respectively, shift to 1615 and 1575 cm(-1) in the complexes. After dissolution in methanol, complex [Co(oflo)(2)]. 4H(2)O crystallizes as [Co(oflo)(2)(MeOH)(2)]. 4MeOH, where Co(II) ion is in an octahedral environment of oxygen atoms. This compound crystallizes in the triclinic system, spatial group P-1, with unit cell dimensions a = 9.3670(12), b = 11.4135(17), c = 11.851(2) A y alpha = 71.999(14), beta = 73.698(12), gamma = 83.528(14) degrees. Magnetic properties (effective magnetic moment 5.02 BM) and visible spectrum (bands at 490, 510, and 1152 nm) are characteristic of such an octahedral geometry. (1)H- and (13)C-NMR spectra of the Zn(II) complex indicate only small structural changes in ofloxacin upon coordination to the metallic site. Copyright 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:2416-2423, 2002