Synthesis, Characterization and Antibacterial Activities of New Pd(II) And Pt(IV) Complexes of Some Unsymmetrical Tetradentate Schiff Bases
W. H. Hegazy *
College of Science, Suez Canal University, Suez, Egypt and Chemistry Department, College of Science, King Faisal University, Al-Ahsa 31982, Saudi Arabia.
A. E.-D M. Gaafar
Photochemistry Department, National Research Centre, Dokki, Giza, Egypt.
*Author to whom correspondence should be addressed.
Abstract
New palladium (II) and platinum (IV) complexes with a series of unsymmetrical tetradentate Schiff bases derived from aromatic 2-hydroxy aldehydes in an ethanolic medium were synthesized and characterized by elemental analyses, melting points, magnetic susceptibility, thermogravimetry, differential scanning calorimetry (DSC), infrared (IR), and electronic spectral measurements. The purity of the ligands and the metal complexes are confirmed by microanalysis, while the unsymmetrical nature of the ligands was further corroborated by 1H-NMR spectroscopy. Comparison of the IR spectra of the Schiff bases and their metal complexes confirm that the Schiff bases act as tetradentate and coordinated via the two azomethine nitrogens and the two phenolic oxygens. Magnetic moments and electronic spectral data confirm square planar geometry for the Pd(II) and Pt(IV) complexes. Thermal studies reveal a general decomposition pattern, whereby the complexes decomposed partially in a single step due to loss of part of the organic moiety. The Schiff bases and their complexes were screened in vitro against 10 human pathogenic bacteria.
Keywords: Palladium (II) complexes, platinum (IV) complexes, Schiff bases, antibacterial activity, MICs