Spectral properties of Eu(III) compound with antibacterial agent ciprofloxacin (cfqH). Crystal structure of [Eu(cfqH)(cfq)(H2O)4]Cl2 · 4.55H2O

A novel europium complex of fluoroquinolone ciprofloxacin (cfqH) with formula [Eu(cfqH)(cfq)(H2O)4]Cl2 · 4.55H2O (1) was synthesized and its crystal structure determined by X-ray crystallography. The coordination number of europium is eight and in this structure two bidentate, O,O-bonded quinolone molecules and four aqua ligands are coordinated to the metal. One molecule of quinolone is anionic whereas the other is zwitterionic. Additionally, two chloride ions are also present in the structure to compensate the charge of the europium(III) whilst disordered solvent water molecules too are present. The spectral properties (IR, Raman, luminescence) of compound 1 were studied. Analysis of the Stark structure of the luminescence spectra was carried out and the scheme of the electronically excited states and photophysical processes of compound 1 was arranged. The spectral properties show that europium–ciprofloxacin complexes could be suitable for various applications based on their solution-state stability as measured by 1H and 19F NMR.

Graphical abstractA novel europium(III) complex of antibacterial agent ciprofloxacin (cfqH) with formula [Eu(cfqH)(cfq)(H2O)4]Cl2 · 4.55H2O was synthesized and its crystal structure was determined by X-ray crystallography. The spectral properties (IR, Raman, luminescence, NMR) of the isolated compound were studied and analysis of the Stark structure of the luminescence spectra was carried out.Figure optionsDownload full-size imageDownload as PowerPoint slide