Synthesis, Characterization and Antibacterial Activities of New Pd(II) And Pt(IV) Complexes of Some Unsymmetrical Tetradentate Schiff Bases

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 1 H-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

Synthesis and Characterization of Schiff Base Metal Complexes Derived from Cefotaxime with 1<i>H</i>-indole-2,3-dione (Isatin) and 4-N,N-dimethyl-aminobenzaldehyde

“…The spectra of the two diamagnetic Pd(II) complexes (C 5 and C 11 ) exhibited two additional bands attributed to the transitions 1 A 1 g → 1 A 2 gand 1 A 1 g → 1 B 1 g respectively of square planar geometry [20] [42]. The Pt(IV) complexes (C 6 , C 12 ) were diamagnetic and their spectra exhibited the appearance of one additional band attributed to [42]. The molar conductivity measurements of all metal complexes in DMSO (10 −3 M) suggested that the complexes were nonelectrolyte [43].…”

Synthesis, Characterization and Antibacterial Activity of New Complexes of Some Lanthanide Ions with 15-Crown-5 and 18-Crown-6

“…After (2 hrs) a clear yellow solution was obtained, filtered and treated with benzene in a separating funnel in order to extract all the excess of picric acid. The final step of crystal formation can be done by reducing the volume of the solution at (40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50) o C). After cooling the solution in an ice bath for (1 hr.)…”

“…Chelation reduces the polarity of the Ln (III) ions due to the partial sharing of lanthanides positive charge with the oxygen donor atoms and possibly the electron delocalization over the whole chelate ring system. Therefore, chelation increases the lipophilic nature of the central metal atom, which enhances the penetration of the complexes into the lipid membrane of the microorganism cell wall blocking of the metal binding sites in the enzymes of the microorganism and thus raising the activity of the complex and restricts the further growth of the organism 47,48 .…”

“…The nature of these interactions is determined by the characteristics of the metal complex. For instance, all cationic metal complexes exhibit electrostatic interactions with the polyanionic DNA molecule, metal complexes with extended aromatic systems may intercalate between the DNA base pairs while mixed -ligand metal complexes were found to be particularly useful because of their high potential to bind DNA via a multitude of interactions and to cleave the duplex by virtue of their intrinsic, chemical, electrochemical and photochemical reactivities 48,49 .…”

Synthesis, Characterization, and Photophysical Studies of Some Novel Ruthenium(II) Polypyridine Complexes Derived from Benzothiazolyl hydrazones

“…were attributed to coordinated water molecule and bands observed due to ]Ru-N and ]Ru-O stretching vibrations in the range of 520-495 cm −1 and 450-418 cm −1 , respectively [17,[22][23][24][25].…”