Kamal Y. El-Baradie

Synthesis and characterization of Cu(II), Co(II) and Ni(II) complexes of a number of sulfadrug azodyes and their application for wastewater treatment

The azodye ligand (HL(1)) was synthesized from the coupling of sulfaguanidine diazonium salt with 2,4-dihydroxy-benzaldehyde while the two ligands, HL(2) and HL(3), were prepared by the coupling of sulfadiazine diazonium salt with salicylaldehyde (HL(2)) and 2,4-dihydroxy-benzaldehyde (HL(3)). The prepared ligands were characterized by elemental analysis, IR, (1)H NMR and mass spectra. Cu(II), Co(II) and Ni(II) complexes of the prepared ligands have been synthesized and characterized by various spectroscopic techniques like IR, UV-Visible as well as magnetic and thermal (TG and DTA) measurements. It was found that all the ligands behave as a monobasic bidentate which coordinated to the metal center through the azo nitrogen and α-hydroxy oxygen atoms in the case of HL(1) and HL(3). HL(2) coordinated to the metal center through sulfonamide oxygen and pyrimidine nitrogen. The applications of the prepared complexes in the oxidative degradation of indigo carmine dye exhibited good catalytic activity in the presence of H2O2 as an oxidant. The reactions followed first-order kinetics and the rate constants were determined. The degradation reaction involved the catalytic action of the azo-dye complexes toward H2O2 decomposition, which can lead to the generation of HO radicals as a highly efficient oxidant attacking the target dye. The detailed kinetic studies and the mechanism of these catalytic reactions are under consideration in our group.

Complex formation, thermal behavior and stability competition between Cu(II) ion and Cu0 nanoparticles with some new azo dyes. Antioxidant and in vitro cytotoxic activity

Four triazole and thiadiazole-based azo chromophores namely [(E)-4-((1H-1,2,4-triazol-3-yl)diazenyl)benzene-1,3-diol.(HL(1)), (E)-4-((5-(methylthio)-1H-1,2,4-triazol-3-yl)diazenyl)benzene-1,3-diol.(HL(2)), (E)-4-((1,3,4-thiadiazol-2-yl)diazenyl)benzene-1,3-diol.(HL(3)) and (E)-4-((5-mercapto-1,3,4-thiadiazol-2-yl)diazenyl)benzene-1,3-diol.(HL(4))] were synthesized and characterized by elemental analyses, IR, UV-Vis as well as mass spectroscopy. Cu(II) complexes of the investigated azo dyes have been synthesized and characterized by elemental analyses, IR, electronic and ESR spectra, magnetic susceptibility and thermogravimetric analyses. The bond lengths and bond angles have been calculated to confirm the geometry of the ligands and their Cu(II) complexes. The mode of interaction of the azodyes to copper nanoparticles was described as coordination mode of charged dye molecules on the colloidal Cu(0) surface through anchoring OH(-) group. The apparent association constants of the colloidal copper nanoparticles azodye complexes in solution were evaluated using the spectral method and compared with the formation constant of the Cu(II) azo complexes. The antitumor and antioxidant activities of the synthesized azo dyes and their Cu(II) azo complexes have been evaluated.

Novel platinum(II) and (IV) complexes of naphthaldimine schiff bases

Naphthaldimines containing N2O2 donor centers react with platinum(II) and (IV) chlorides to give two types of complexes depending on the valence of the platinum ion. For [Pt(II)], the ligand is neutral, [(H2L1)PtCl2]·3H2O (1) and [(H2L3)2Pt2Cl4]·5H2O (3), or monobasic [(HL2)2Pt2Cl2]·2H2O (2) and [(HL4)2Pt]·2H2O (4). These complexes are all diamagnetic having square-planar geometry. For [Pt(IV)], the ligand is dibasic, [(L1)Pt2Cl4(OH)2]·2H2O (5), [(L2)Pt3Cl10]·3H2O (6), [(L3)Pt2Cl4(OH)2]·C2H5OH (7) and [(L4)Pt2Cl6]·H2O (8). The Pt(IV) complexes are diamagnetic and exhibit octahedral configuration around the platinum ion. The complexes were characterized by elemental analysis, UV-Vis and IR spectra, electrical conductivity and thermal analyses (DTA and TGA). The molar conductances in DMF solutions indicate that the complexes are non-ionic. The complexes were tested for their catalytic activities towards cathodic reduction of oxygen.

Mononuclear and homobinuclear cobalt(II), nickel(II) and copper(II) complexes with mono and bis-azocompounds derived from 2,7-dihydroxynaphthalene and anthranilic acid or o-aminophenol

Two new series of mononuclear and homobinuclear Co(II), Ni(II) and Cu(II) complexes with mono- and bis-azo compounds derived from 2,7-dihydroxynaphthalene and anthranilic acid or o-aminophenol are prepared and characterized by elemental and thermal analyses, conductance, IR, electronic, ESR spectra and magnetic moment measurements. The ligand field splitting parameters and Racah constant are calculated. The spectral and magnetic results obtained are utilized to determine the geometries around the metal(II) ion. The geometry of the complex formed depends on the structure of the ligand and the type of metal(II) ion. The mode of bonding of the ligand with the metal ions is deduced from IR spectra.

π-π* Molecular charge transfer complexes of antipyrineSchiff bases with 1,4-benzoquinone derivatives as π-acceptors

SummarySpectrophotometric studies of compounds formed by several substituted antipyrineSchiff bases as electron donors with 2,3-dichloro-5,6-dicyano-benzoquinone, chloranilic acid, and chloranil as electron acceptors have given results that are consistent with 1:1 charge transfer complexes. Transition energies, oscillator strengths, and dipole moments of the complexes as well as the effect of solvent upon their stability are discussed. Also their free energies and absorption cross sections have been determined.ZusammenfassungSpektrophotometrische Untersuchungen von ausSchiffschen Basen des Antipyrintyps als Elektronendonatoren und 2,3-Dichlor-5,6-dicyanobenzochinon, Chloranilsäure und Chloranil als Elektronenakzeptoren gebildeten Verbindungen zeigen die Entstehung vonCharge-transfer-Komplexen der Stöchiometrie 1:1. Neben der Berechnung von freien Energien und Absorptionsquerschnitten werden Übergangsenergien, Oszillatorstärken, Dipolmomente und der Einfluß des Lösungsmittels auf die Stabilität der Komplexe diskutiert.

Synthesis and characterization of self-assembled coordination polymers of N-diaminomethylene-4-(3-formyl-4-hydroxy-phenylazo)-benzenesulfonamide

The azo dye ligand N-diaminomethylene-4-(3-formyl-4-hydroxy-phenylazo)-benzenesulfonamide (HL) and Cu(II), Co(II), and Mn(II) coordination polymers were synthesized in addition to a non-polymeric Pd(II) complex. In all complexes, the ligand bonds to the metal ion through the formyl and α-hydroxy oxygen atoms. The sulfonamide oxygen also coordinates to the metal. The complexes are formulated as [ML2] n , where M = Cu(II), Co(II), and Mn(II), and [ML(Cl)(H2O)], where M = Pd(II). On the basis of spectral studies and magnetic susceptibility measurements, an octahedral geometry was assigned to Co(II) and Mn(II) complexes, tetragonally elongated octahedral geometry for Cu(II) complex, while the Pd(II) complex was found to be square planar. Crystallization of Cu(II) complex from DMF afforded single crystals of general formula {[Cu(L)2] · 3DMF} n (2). X-ray structural analysis of 2 revealed that each Cu(II) adopts elongated octahedral geometry affording 1-D chains. The chains are connected by hydrogen bonds, resulting in the formation of 2-D supramolecular assemblies. The crystal structure of HL has also been determined and discussed. Cyclic voltammetric behavior of the ligand and some complexes are also discussed.

4-[(3-Formyl-4-hydroxy-phen-yl)diazen-yl]-N-(pyrimidin-2-yl) benzene-sulfonamide

The title molecule, C17H13N5O4S, has a trans configuration with respect to the diazenyl (azo) group. The pyrimidine ring and the terminal benzene ring are inclined at angles of 89.38 (4) and 1.6 (6)°, respectively, with respect to the central benzene ring. The conformation of the molecule is in part stabilized by an intramolecular O—H⋯O hydrogen bond. In the crystal structure, molecules related through inversion centers form hydrogen-bonded dimers involving the sulfonamide N—H group and the N atom of the pyrimidine ring.

Dibromido(2,3,9,10-tetra­methyl-1,4,8,11-tetra­azacyclo­tetra­deca-1,3,8,10-tetra­ene)cobalt(III) bromide

In the title compound, [CoBr2(C14H24N4)]·Br, the CoIII ion is located on an inversion centre and possesses a distorted octahedral coordination geometry in which four nitrogen donors of the ligand molecule are in the equatorial plane and two Br− ions occupy both the axial sites to give a trans isomer. The Br- counter- anion is also located on an inversion centre.

1-[4-(Diamino­methyl­eneamino­sulfon­yl)phenyl­iminiometh­yl]-2-naphtholate N,N-dimethyl­formamide disolvate

The asymmetric unit the title compound, C18H16N4O3S·2C3H7NO, contains a molecule in a zwitterionic form with a deprotonated hydroxyl group and an iminium group, and two dimethylformamide solvent molecules. The dihedral angles of the guanidine group and the naphthyl ring system with respect to the central benzene ring are 76.04 (7) and 3.45 (9)°, respectively. The conformation of the molecule may be influenced, in part, by two intramolecular hydrogen bonds, while in the crystal structure, intermolecular hydrogen bonds form one-dimensional chains along [010].

Synthesis and Characterisation of Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) Complexes with m-Aminobenzoic Hydrazide and Some of Its Arylidene Derivatives

Abstract The preparation and characterisation of a series of new coordination compounds of Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) containing m-aminobenzoic hydrazide and some of its arylidene derivatives are reported. Attempts have been made to ascertain their probable structures on the basis of elemental analysis, molar conductance, TGA, ir, electronic and esr spectra as well as magnetic measurements. The ir-spectra suggest that the ligand coordinates to the metal ions via the oxygen of the carbonyl group and β-nitrogen atom.