Tetra- and hexadentate Schiff base ligands and their Ni(II), Cu(II) and Zn(II) complexes. Synthesis, spectral, magnetic and thermal studies

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 86; pp. 276 - 288
• Main Authors: Ismail, Tarek M.A., Saleh, Akila A., Ghamry, Mosad A. El
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 01.02.2012
• Subjects: Absorption; Copper - chemistry; Differential Thermal Analysis; Electron Spin Resonance Spectroscopy; Electrons; Ligands; Magnetic; Magnetics; Mass Spectrometry; Nickel - chemistry; Schiff base complexes; Schiff base derivatives; Schiff Bases - chemical synthesis; Schiff Bases - chemistry; Solutions; Spectral; Spectrophotometry, Infrared; Temperature; Thermal properties; Thermogravimetry; Zinc - chemistry; Thermal properties; Spectral; Schiff base derivatives; Magnetic; Schiff base complexes
• ISSN: 1386-1425; 1873-3557
• DOI: 10.1016/j.saa.2011.10.037

[Display omitted] ► New tetradentate N 2O 2, N 4 and hexadentate N 4O 2 Schiff bases were prepared. ► The structures of these compounds were studied by IR, UV–Vis, 1H NMR and mass spectra. ► The solid complexes of the prepared Schiff bases with Ni(II), Cu(II) and Zn(II) ions were isolated. ► The spectral, magnetic and thermal properties of these complexes were studied. ► The TG analyses suggest high stability for most complexes. Tetradentate N 2O 2, N 4 Schiff bases, 1,2-bis(4-oxopent-2-ylideneamino) benzene (BOAB), 1-(4-oxopent-2-ylideneamino-2-[(2-hydroxyphenyl)ethylideneamino] benzene (OAHAB), 7,16-bis(4-chlorobenzylidene)-6,8,15,17-tetra-methyl-7,16-dihydro -5,9,14,18-tetraza-dibenzo[a,h] cyclo tetradecene (BCBDCT), 7,16-bis(2-hydroxy-benzylidene)-6,8,15,17-tetramethyl-7,16-dihydro-5,9,14,18-tetraza-dibenzo [a,h] cyclo tetradecene (BHBDCT) and hexadentate N 4O 2 Schiff bases, 2,4-bis {2-[1-(2-hydroxyphenyl) ethylideneamino] phenylimino}-3-(2-hydroxybenzylidene) pentane (BHAPHP), 2,4-bis {2-[1-(2-hydroxyphenyl) ethylideneamino] phenylimino}-3-(4-chlorobenzylidene) pentane (BHAPCP) were prepared and characterized by elemental analysis, IR, UV–Vis, 1H NMR and mass spectra. The solid complexes of the prepared Schiff base ligands with Ni(II), Cu(II) and Zn(II) ions were isolated and characterized by elemental and thermal analyses, IR, electronic and ESR spectra as well as conductance and magnetic susceptibility measurements. The results showed that most complexes have octahedral geometry but few can attain the tetrahedral arrangement. The TG analyses suggest high stability for most complexes followed by thermal decomposition in different steps. The kinetic and thermodynamic parameters for decomposition steps in Cu(II) complexes thermograms have been calculated.