Abstract
This study reports the preparation and characterization of Ru3+, Pt4+ and Ir3+ complexes of lomefloxacin (LOM; (RS)-1-ethyl-6,8-difluoro-7-(3-methylpiperazin-1-yl)-4-oxo-quinoline-3-carboxylic acid). The complexes were characterized using elemental analyses (C, H, and N), molar conductance, IR, UV-Vis, magnetic moment, H-1-NMR, X-ray powder diffraction, scanning electron microscopy, transmittance electron microscopy and thermogravimetric analyses. The infrared and UV-Vis spectra of LOM metal chelations with their different interligand transitions are fully assigned. LOM behaves as a neutral monodentate ligand complexed to the metal ions via the piperazine-N moiety and the complexes have octahedral geometrical structures. Molar conductance data reveal that all of these chelates are non electrolytes with 1:3 molar ratio for Ru(III) and Ir(III) chelates to LOM whereas, Pt(IV) with LOM ligand has a 1:2 molar ratio. The complexes of LOM have the general formulas [M(L)(n)(Cl)(x)]center dot yH(2)O (1) M = Ru3+, L: LOM: NH4, n = 3, x = 3, y = 3; (2) M = Pt4+, L: LOM-NH4, n = 2, x = 4, y = 4 and (3) M = Ir3+, L: LOM-NH4, n = 3, x = 3, y = 3. X-ray powder diffraction is used as tool to estimate the crystallinity of coordination compounds as well as to inform about their geometrical structures. Thermogravimetric analysis (TG-DTG) was utilized to differentiate between coordinated and hydrated water molecules. The thermal behavior of LOM complexes was investigated and the thermal decomposition pathways have been postulated showing that the final product is metal oxide.