Synthesis, Crystal Structure And Properties Of Fluoro-substituted β-Diketones Complexes

The coordination compounds of metals with fluoro-substitutedβ-diketones are more and more important as their various structures and extensive uses in the field of MOVCD, bioactivity, and material science etc. Therefore we designed and synthesized some new fluoro-substitutedβ-diketones ligands and their complexes with transition metals and lanthanide Eu(â…¢) in the paper.The main work is as follows:1. Eleven fluoro-substitutedβ-diketones complexes were synthesized from aromatic ketones and ethyl trifluoracetate by classical Claisen condensation using CH₃ONa as strong base. And their structures were determined by means of ¹H NMR, MS and IR spectra. Inaddition HL⁵ was characterized by X-ray single-crystal diffraction. ¹H NMR results showed that all fluoro-substitutedβ-diketones nearly existed in the enol form in chloroform solvent due to the important role of trifluoromethyl group.2. Eight 1H-pyrazoles complexes were synthesized from fluoro-substitutedβ-diketones and hydrazine monohydrate. Their structures were characterized by means of ¹H NMR, MS and IR spectra.3. A series of Cu(â…¡),Co(â…¡) and Ni(â…¡) complexes were prepared from the syntheszied fluoro-substitutedβ-diketone ligands HL¹, HL², HL³, HL⁴ and HL⁵, and the strutures of complexes of [Cu(L³)₂Py₂] (1),[Cu(L⁵)₂Py] (2),[Co(L²)₂Py₂] (3),[Co(L⁴)₂Py₂] (4),[Co(L⁵)₂Py₂] (5) were further confirmed by X-ray diffraction.4. Twelve lanthanide Eu(â…¢) ternary complexes withβ-diketones, phenanthroline and bipyridine were synthesized. Their compositions and structures were characterized by means of elemental analysis, IR and TG-DTG IR results showed that theβ-diketones ligands were coordinated to the metal ions acting as enol form, the main absorption peaks of the ligands in IR spectra were red-shifted for the influence of chelating effect. Luminescence spectroscopy of these complexes results showed that the fluorescence intensity of containing second ligands complexes was better than that of containing water, and bipyridine indicated a efficient ligand-to-metal energy transfer than phenanthroline.