Abstract

Mixed Schiff Bases Chelates:Synthesis and Spectroscopic Investigation

Author(s): M. M. El-ajaily1*, N. S. Al-barki1and A.A. Maihub2

Co(II), Ni(II), Cu(II), Zn(II) and Fe(III) mixedSchiff base chelates with Schiff bases were investigat-ed , firstly, Schiff base formed from the condensation of 2-hydroxyacetophenone and tyrosine as primary ligand (L1) and the second one is derived from the reaction of 4-dimethylaminobenzaldehyde and 2-aminophenol as secondary ligand (L2) were synthesized. The Schiff bases and their mixed Schiff base chelates under investigation were charac-terized by using several physiochemical techniques; in terms, CHN elemental analyses, molar conductivity, infra-red, proton nuclear resonance, electronic, mass and electron paramagnetic resonance spectra. The CHN elemental analysis results exhibited the formation of the Schiff bases and their chelates in 1:1:1[M:L1:L2] ratio. The molar conductivity values displayed that Co(II), Ni(II), Cu(II) and Zn(II) mixed Schiff base chelates found to be electro-lytes due to the presence of sodium ions outside the frame of the coordination units of the chelates, however, except the iron(III) mixed Schiff base chelate found to be neutral, confirming the presence of non-electrolytic nature. The infrared spectral data of the mixed Schiff base chelates revealedthe chelation behavior between themetalions and the Schiff bases through the active groups presented in the Schiff bases such as nitrogen atom of the azomethine and oxygen atom of the hydroxylgroup. The signals which obtained from the 1H-NMR spectra of the Schiff bases and their Zn(II) chelate confirmed the chelateformation between the Zn(II) ion and the Schiff bases. The mass spectral fragmentations of the Schiff bases were reported and confirming the formationof the Schiff bases, as well as also the mass spectral fragmentation ofthe iron(III) mixed Schiff base chelate was done. The electron paramagnetic reso-nance spectral data confirmed the results which obtained from the electronic study. Meanwhile, the UV spectral results of the Schiff bases exhibitedthe π→π* (Phenyl reing) and n→π* (C=N and –OH). All transitions and the electronic spectral data of themixed Schiff base chelates suggested the geometrical structureofoctahedral struc-tures.

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