STRUCTURAL STUDY OF COMPLEXES FROM HEXAFLUOROACETYLACETONE, PYRAZOLE, AND ITS PYRAZOLE DERIVATIVE WITH SOME METALS BY FT-IR, AND 1H-NMR

Abstract

The series complex formation nickel(II) or cobalt(III) with hexafluoroacetylacetone, pyrazole, 3,5-dimethylpyrazole, and 3,5-bis(trifluoromethyl)-1H-pyrazole were prepared. The first reaction step included the synthesis of the complex using hexafluoroacetylacetone as a ligand with Co(III) or Ni(II), metals with high spin with π donate and enol-form of the ligand. This formed complex was identified by FT-IR, 1H-NMR spectroscopy, and magnetic susceptibility calculation. Whereas, the second reaction step to produce the complex depended upon mixing water and pyrazole and using it as ligands with Co(III) or Ni(II) a metal, which is a high spin with one donate and the another is aromatic nitrogen atom in a ligand. In the third reaction step, the complexes were produced by mixing water with 3,5-bis(trifluoromethyl)-1H-pyrazole as a ligand with Co(III) or Ni(II) as low spin metal. The analysis of these prepared complexes and their used ligands were done by comparing the results using 1H-NMR and FT-IR spectroscopies. Besides, the magnetic susceptibility calculation was also employed. The results of 1H-NMR spectroscopy and magnetic susceptibility proved that the produced complexes are diamagnetic when the ligand includes the CF3 group. At the same time, the produced complexes are paramagnetic, when the ligand without the CF3 group, which is formed the mixture of water and 3,5-dimethylpyrazole as ligand or water and pyrazole as a ligand with Co(III) or Ni(II) as metal. All the ligands in the paramagnetic complexes were one donate, and another the donated atom in pyrazol is an aromatic nitrogen atom. Therefore all prepared high spin complexes were not evident in the 1H-NMR spectrum because the peaks appear brood that due to high T1 relaxation 1H-NMR time, and the investigation turned out two assignment peaks. This behavior is an attitude to happen the ketone form and enol form phenomenon by using 1H-NMR spectra, and its an evident assignment coupling between hydrogen or carbon atom with a fluorine atom.