Wageih G. Hanna

Synthesis, characterization and antimicrobial activity of cobalt(II), nickel(II)and copper(II) complexes with new asymmetrical Schiff base ligands derived from 7-formyanil-substituted diamine-sulphoxine and acetylacetone

Asymmetric 7-formyanil-substituted-imino-4-(4-methyl-2-butanone)-8-hydroxyquinoline-5-sulphonic acid (Schiff bases), react with CoII, NiII and CuII ions to give 1:2, 1:1 and 2:1 complexes as established by conductometric titrations in 1:1 DMF:H2O. The complexes were investigated by elemental analyses, molecular weight determinations, molar conductance, magnetic moments, thermal analysis, i.r., u.v.–vis. and e.s.r. spectra. The complexes have an octahedral crystal structure and general formula [ML·(OH2)2], where MII = Co, Ni and Cu, and L = Na[7—X—HL], (—X— = (CH2)2, (CH2)3, p-C6H4, o-C6H4). Antimicrobial activity of these new ligands and their transition metal complexes has been screened in vitro on common fungi and bacteria.

Structural and Antimicrobial Studies of Some Divalent Transition Metal Complexes with Some New Symmetrical Bis (7-Formylanil Substituted-Sulfoxine) Schiff Base Ligands

Symmetrical bis (7-formyanil substituted-8-hydroxyquinoline-5-sulfonic acid), Schiff bases, react with Co(II), Ni(II) and Cu(II) ions to give MnL (n=1, 2) complexes as established by conductometric titration in 1 : 1 DMF: H2O. The complexes were identified by elemental analyses, molecular weight determination, thermal analysis, infrared, magnetic moments, electronic absorption, and electron spin resonance spectra. The suggested general geometry for these complexes may have a tetrahedral crystal structure and the general formula is [M2L(OH24], where M(II) = Co, Ni and Cu and L = 7―X―H2 L(―X―= dimethyl, p-phenyl, o-phenyl), while for the, trimethyl, ligand and the tetrahedral crystal structure has the general formula [M2L(OH2)2].Antimicrobial activity of these ligands and their transition metal complexes has been investigated on some common fungi and bacteria. A considerable increase in the biocide acticity of these ligands has been observed on coordination with transition metal ions, therefore, these complexes can be used in the chemotherapy of candidiaces and other fungal skin diseases.

Complexation and determination of palladium (II) ion with para-Cl-phenylazo-R-acid spectrophotometrically

The complexation of para-Cl-phenylazo-R-acid azo dye with Pd(II) has been studied spectrophotometrically. Protonation constant (pK(a)) of the ligand has been calculated and the stability conditional constants of para-Cl-phenylazo-R-acid ligand with palladium ion has been determined at a constant temperature (25.0 degrees C), where the molar ratio of this complex is 1:1 (metal:ligand) with logbeta(1)=3.75, and 1:2 with logbeta(2)=8.55. Solid complex of para-Cl-phenylazo-R-acid has been prepared and characterized on the basis of elemental analysis and FTIR spectral data. A procedure for the spectrophotometric determination of Pd(II) using para-Cl-phenylazo-R-acid as a new azo chromophore is proposed where it is rapid, sensitive and highly specific. Beers law was obeyed in the range 0.50-10.00 ppm at pH 5.0-6.0 to form a violet-red complex (epsilon=7.7 x 10(4) l(-1) mol(-1) cm(-1) at lambda(max)=560 nm). Metal ions such as Cu(II), Cr(III), La(III), Yb(III), Y(III), and Rh(III) interfere with the complex. Ammonium salt of trimellitic acid is used to precipitate some of the interfering ions and a scheme for separation of Pd(II) from a synthetic mixture similar in composition to platinum ore or deposit was made.

Structural and Microbial Studies of some Transition Metal Complexes of 7-Substituted-8-Hydroxyquinoline-5-Sulphonic Acid Ligands

The reaction of 7-substituted derivatives of the ligand 5-sulpho-8-hydroxyquinoline (7-X-HL), (X=H, NH 2 , NO 2 and I), with some biologically important transition metal ion such as {Cr(III), Fe(III), Mn(II), Fe(II), Co(II), Ni(II), and Cu(II)} was investigated. The formation of ML n (n=1, 2) complexes of the ligand Na[7-I-HL] has been established by conductometric titrations in 10% (v/v) ethanol-water. The complexes of the ligands with all of the above transition metal ions which have been synthesized were characterized by elemental analyses, molecular weight determinations, X-ray diffraction (XRD), magnetic moments (µ eff ), and thermal analyses (DTA and TG). The data suggest the composition of these complexes, which have an octahedral coordination. The general formula is Na 2 [ML 2 (H 2 O) 2 ]·4H 2 O where M(II)=Mn, Fe, Co, Ni and Cu. The thermal analyses of the complexes show that for Na 3 [ML 3 ]·6H 2 O where M(III)=Cr and Fe all water molecules are lattice water. The antibacterial activity of these ligands and their divalent transition metal complexes has been determined on gram-positive ( Sarcina lutea ) and gram-negative ( Escherichia coli ) bacteria at 37°C, and antifungal activity has been determined on common fungi viz . ( Aspergillus niger , and Candida albicans ) at 30°C. A considerable increase in the biocidal activity of these ligands on being coordinated with transition metal ions has been reported. These compounds can be recommended to use for the chemotherapy of candidiaces and other fungal skin diseases.

Preparation and Identification of a New [Cr2(NTA)2(μ-OH2)]·2H2O Complex

[Cr2(NTA)2(μ-OH2)]·2H2O is prepared by heating nitrilotriacetic acid (H3NTA) with an aqueous suspension of freshly precipitated Cr2O3·nH2O. Elemental analysis, IR spectra, UV/vis spectra, X-ray diffraction, thermogravimetric analysis, mass spectra and magnetic susceptibility measurements suggest the existence of a Cr-Cr bond. One of the three water molecules acts as a bridging ligand (μ-H2O) while the other two are waters of crystallization.

Structural studies of reaction products between paramolybdate anion and some cationic [metal(II) and (III)-(ethylenediamine)n] complexes utilized as new photocatalysts under UV–VIS light illumination

Abstract Five cationic transition metal (ethylenediamine) complexes (M=Cr(III), Co(III), Ni(II), and Cu(II)):paramolybdate anion (Mo 7 O 24 6− ) have been synthesis and characterized via their elemental analysis, magnetic susceptibility ( μ eff ), thermal analysis (TG and DTA), FTIR spectra, and X-ray diffraction (XRD). The FTIR study suggests that the compounds prepared be of the ion-pair type ([M(en) n ] m ·Mo 7 O 24 ). Thermal study showed that molybdenum in the Cr(III), and Co(III) compounds is reduced from oxidation state (VI) to (V) at high temperature. The stoichiometries of the resulting mixed oxides at elevated temperatures (500–750°C) are: Cr 2 O 3 ·7MoO 2.5 , Co 2 O 3 ·7MoO 2.5 , 6CoOCl·7MoO 2.5 , 3NiO·7MoO 3 and 3CuO·7MoO 3 . Above 750°C the molybdenum oxide in the ion-pair compounds start the sublimation process. X-ray diffraction of [Cr(en) 3 ]·Mo 7 O 24 , [Co(en) 3 ]·Mo 7 O 24 , and [Cu(en) 2 (H 2 O) 2 ] 3 ·Mo 7 O 24 shows that these complexes are crystalline solids with a similar structure, while the [Ni(en)(H 2 O) 4 ] 3 ·Mo 7 O 24 , and [Co(en)(H 2 O) 2 Cl 2 ] 6 ·Mo 7 O 24 ion-pair compounds display a different structure. A novel technique based on photocatalysis to eliminate Cr(VI) ions, a toxic pollutant in the environment, was applied. The photoreduction of Cr(VI) to Cr(III) ion in aqueous suspensions using new-mixed oxides as photocatalysts (Cr 2 O 3 ·MoO 2.5 , Co 2 O 3 ·MoO 2.5 , NiO·MoO 3 , and CuO·MoO 3 ) under air-equilibration and irradiation by a medium pressure mercury lamp (UV–VIS) was investigated.

Preparation, characterization and determination of acid dissociation and stability constants of some acid divalent-metal 1 : 2 nitrilotriacetate complexes

H2[MII(HNTA)2]·xH2O complexes of eleven divalent metals were prepared. These complexes were characterized via elemental analysis, IR spectra, TGA, DTA and 1H NMR. pKa1 and pKa2 of these acids were determined together with their log β 1 and log β 2 as metal complexes.

Dithizone and carbazone complex compounds as initiators and γ -radiation anti-degradation agents for poly(methyl methacrylate)

It has been proved that lead dithizone and carbazone complex compounds act as adequate initiators and indicators for radical polymerization of methylmethacrylate. The color change observed during the polymerization process was attributed to the change in structure of the complex compounds according to tautomerization mechanism. Improvements to both polydispersity and relative crystallinity were observed in presence of lead dithizone and carbazone complex compounds. Better protection against gamma radiation was noticed ascertained through molecular mass measurements. A convincing reaction mechanism was also given.

Preparation, characterization and thermal studies of the paramolybdates of some cobaltammine complexes

Abstract Five cobaltammine-paramolybdate ion-pair complexes have been prepared and characterized via their nitrogen content and IR study. The complexes were subjected to thermogravimetric and differential thermal analyses. The IR study suggests that the compounds prepared are of the ion-pair type. Thermal treatment showed that molybdenum in complexes containing five or six ammonia ligands per cation is reduced from oxidation state VI to V, a phenomenon which did not take place in complexes containing four ammonia ligands. The IR study of the thermally decomposed compounds revealed the resolution of the originally broad Mo=O and Mo-O-Mo bands.