Synthesis and spectroscopic studies of levofloxacin uni-dentate complexes of Ru(II), Pt(IV) and Ir(III): Third generation of quinolone antibiotic drug complexes

The monobasic unidentate levofloxacin (LEV; (S)-9-fluoro-2,3-dihydro-3-methyl-10-(4-methylpiperazin-1-yl)-7-oxo-7H-pyrido[1,2,3-de]-1,4―benzoxazine-6-carboxylic acid) complexes of Ru(III), Pt(IV) and Ir(III) were prepared and well discussed using elemental analyses (CHN), molar conductance, infrared, electronic, effective magnetic moment, 1H-NMR, X-ray powder diffraction, scanning electron microscopy, transmittance electron microscopy and thermogravimetric (TG/DTG) analyses. The IR and electronic spectra of LEV complexes with their assignments were discussed in details which were confirmed that LEV is binding to the metal ions as a neutral unidentate ligand through the nitrogen atom of 4-methylpiperazin-1-yl moiety. The molar ratio of Ru(III) and Ir(III) chelates is 1:3 (Metal: LEV), while Pt(IV) complex has a 1:2 M ratio. The general formulas of LEV complexes have been designed as [M(L)n(Cl)x]·yH2O ((1) M = Ru3 +, L: LEV, n = 3, x = 3, y = 8; (2) M = Pt4 +, L: LEV, n = 2, x = 4, y = 4 and (3) M = Ir3 +, L: LEV, n = 3, x = 3, y = 6. The X-ray powder diffraction was used as technique to estimate the particle size of LEV complexes. Thermogravimetric analysis (TG-DTG) was utilized to identify the presence of coordinated, uncoordinated water molecules, mass losses and residual products.