M.A. Zayed

Spectroscopic study of molecular structures of novel Schiff base derived from o-phthaldehyde and 2-aminophenol and its coordination compounds together with their biological activity.

New Schiff base (H(2)L) ligand is prepared via condensation of o-phthaldehyde and 2-aminophenol. The metal complexes of Cr(III), Mn(II), Fe(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) with the ligand are prepared in good yield from the reaction of the ligand with the corresponding metal salts. They are characterized based on elemental analyses, IR, solid reflectance, magnetic moment, electron spin resonance (ESR), molar conductance, (1)H NMR and thermal analysis (TGA). From the elemental analyses data, the complexes are proposed to have the general formulae [M(L)(H(2)O)n].yH(2)O (where M=Mn(II) (n=0, y=1), Fe(II) (n=y=0), Co(II) (n=2, y=0), Ni(II) (n=y=2), Cu(II) (n=0, y=2) and Zn(II) (n=y=0), and [MCl(L)(H(2)O)].yH(2)O (where M=Cr(III) and Fe(III), y=1-2). The molar conductance data reveal that all the metal chelates are non-electrolytes. IR spectra show that H(2)L is coordinated to the metal ions in a bi-negatively tetradentate manner with ONNO donor sites of the azomethine N and deprotonated phenolic-OH. This is supported by the (1)H NMR and ESR data. From the magnetic and solid reflectance spectra, it is found that the geometrical structures of these complexes are octahedral (Cr(III), Fe(III), Co(II) and Ni(II) complexes), tetrahedral (Mn(II), Fe(II) and Zn(II) complexes) and square planar (Cu(II) complex). The thermal behaviour of these chelates is studied and the activation thermodynamic parameters, such as, E*, Delta H*, DeltaS* and Delta G* are calculated from the DrTGA curves using Coats-Redfern method. The parent Schiff base and its eight metal complexes are assayed against two fungal and two bacterial species. With respect to antifungal activity, the parent Schiff base and four metal complexes inhibited the growth of the tested fungi at different rates. Ni(II) complex is the most inhibitory metal complex, followed by Cr(III) complex, parent Schiff base then Co(II) complex. With regard to bacteria, only two of the tested metal complexes (Mn(II) and Fe(II)) weakly inhibit the growth of the two tested bacteria.

Synthesis, structural characterization and antimicrobial activity evaluation of metal complexes of sparfloxacin

The synthesis and characterization of binary Cu(II)- (1), Co(II)- (2), Ni(II)- (3), Mn(II)- (4), Cr(III)- (5), Fe(III)- (6), La(III)- (7), UO(2)(VI)- (8) complexes with sparfloxacin (HL(1)) and ternary Cu(II)- (9), Co(II)- (10), Ni(II)- (11), Mn(II)- (12), Cr(III)- (13), Fe(III)- (14), La(III)- (15), UO(2)(VI)- (16) complexes with sparfloxacin (HL(1)) and DL-alanine (H(2)L(2)) complexes are reported using elemental analysis, molar conductance, magnetic susceptibility, IR, UV-Vis, thermal analysis and (1)H-NMR spectral studies. The molar conductance measurements of all the complexes in DMF solution correspond to non-electrolytic nature. All complexes were of the high-spin type and found to have six-coordinate octahedral geometry except the Cu(II) complexes which were four coordinate, square planar and U- and La-atoms in the uranyl and lanthanide have a pentagonal bipyramidal coordination sphere. The antimicrobial activity of these complexes has been screened against two gram-positive and two gram-negative bacteria. Antifungal activity against two different fungi has been evaluated and compared with reference drug sparfloxacin. All the binary and ternary complexes showed remarkable potential antimicrobial activity higher than the recommended standard agents. Ni(II)- and Mn(II) complexes exhibited higher potency as compared to the parent drug against gram-negative bacteria.

Comparative study on the fragmentation of some simple phenolic compounds using mass spectrometry and thermal analyses

The fragmentation pathways of 2-hydroxyphenol and 2,3-di-hydroxyphenol have been examined using electron impact mass spectrometry in comparison with thermal analyses (TGA and DTA). Both the decomposition modes were investigated, and the fragmentation pathways were suggested. The combined use of mass spectrometry and thermogravimetry (MS and TG) in the analysis of 2-hydroxyphenol and 2,3-di-hydroxyphenol allowed the characterization of the fragmentation pathway in MS which was the objective of this research. The major pathway of hydroxyphenol includes successive loss of CHO, while 2,3-di-hydroxyphenol the major pathway involved loss of H2O followed by CO. There was virtually no ring disintegration until the majority of the attached groups were lost in 2-hydroxyphenol, while in 2,3-di-hydroxyphenol a complete decomposition occurred. On the other hand, an O atom remains attached to five-membered ring in a cyclopentanone form as a result of the stability of PG in comparison with PC. The thermal decomposition and mass spectral fragmentation of the hydroxybenzene are also correlated with the electron delocalization of their ring system. # 2001 Elsevier Science B.V. All rights reserved.

Thermal and spectroscopic investigation of novel Schiff base, its metal complexes, and their biological activities

AbstractThe complexing behavior of H2L ((N,N’Z,N,N’E)-N,N’-(ethane-1,2-diylbis(oxy)bis(2,1-phenylene)bis(methanylylidene)bis(1-hydrazinylmethanethioamide)) toward the transition metal ions namely Fe(III), Co(II), Ni(II), Cu(II), Cd(II), and Zn(II) have been examined by elemental analyses, magnetic measurements, electronic, IR, and 1H-NMR. Thermal properties and decomposition possibilities of all complexes are suggested. The interpretation of all thermal decomposition stages has been evaluated. The free ligand and its metal complexes have been tested in vitro against Escherichia coli, Proteus vulgaris, Bacillus subtilis, and Staphylococcus aurous bacteria in order to assess their antimicrobial potential. The results indicate that the metal complexes are also found to have more antimicrobial activity than the parent ligand.Graphical AbstractThe proposed structure of complexes. Novel Schiff base and its metal complexes were prepared and characterized based on elemental analyses, IR, 1H-NMR, magnetic moment, molar conductance, and thermal analyses techniques. Complexes of 1:1 [Metal]:[Ligand] ratio for Fe(III), Co(II), Ni(II), Cu(II), and Zn(II) are formed. They are electrolytes in which ligand coordinated to the metal ions in a uni-negative hexa-dentate manner with O2N2 donor sites of the etheric O, and azomethine N atoms and have octahedral geometry.

Two Spectrophotometric Assays for Dopamine Derivatives in Pharmaceutical Products and in Biological Samples of Schizophrenic Patients Using Copper Tetramine Complex and Tri-iodide Reagent

Two simple, rapid, and sensitive spectrophotometric methods are proposed for the determination of levodopa (LD). The first method is based on coupling of 4-aminoantipyrine (4-AAP) with one of the dopamine derivatives (LD, CD) to give a new ligand that reacts with copper tetramine complex to give intensely colored chelates. The colored products are quantified spectrophotometrically at 525 and 520 nm for LD and CD, respectively. The optimization of the experimental conditions is described. The method has been used for the determination of

Structure-stability relationship of copper(II)-indol carboxylic acid derivative complexes from spectrophotometric, thermogravimetric and potentiometric studies

19.7

Phenolic-iodine redox products: Mass spectrometry, thermal and other physico-chemical methods of analyses

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Hysteroscopic Myomectomy of Large Submucous Myomas in a 1-Step Procedure Using Multiple Slicing Sessions Technique.

69.0

Structure identification of substituted phenol redox products by: thermogravimetric and differential thermal analysis

and

Biological potential study of metal complexes of sulphonylurea glibenclamide on the house fly, Musca domestica (Diptera-Muscidae): preparation, spectroscopic and thermal characterization.

18.1