Aref A. M. Aly

Mixed Ligand Complexes of 5-arylazo-8-hydroxyquinoline and α-amino Acids with Co(II), Ni(II) and Cu(II)

Ten mixed ligand complexes of the type [M(X-QA)(aa)] and [Ni(X-QA)2(Haa)(H2O)],where X-HQA=5-arylazo-8-hydroxyquinoline derivatives, M=Co(II) orCu(II) and Haa=glycine (gly), alanine (ala) or methionine (met), have been prepared. The complexes have been characterized by elemental analysis, IR and electron spectra and thermal analysis. A tetrahedral structure has been proposed for the cobalt(II) and copper(II) complexes with bidentate coordination of amino acids. The nickel(II) complexes have been assigned an octahedral structure with the amino acids acting as monodentate ligands. The thermal behaviour of the complexes has been studied before and after γ-irradiation.

Complexes of tris(o-phenanthroline)nickel(II) and copper(II) bromide with dithiocarbamates derived from α-amino acids

Complexes of 1,10-o-phenanthroline (o-phen)-NiII and CuII with dithiocarbamates derived from α-amino acids (glycine, phenylalanine, alanine, methionine and tryptophan) were synthesized and characterized by chemical analysis, spectral and thermal studies and by biological screening; the complexes are non-electrolytes. The empirical formula are [Ni(o-phen)2(aadtc)] and [Cu2(o-phen)2(phaladtc)(H2O)2Br2] where, aadtc = glycinyl-, phenylalaninyl-, alaninyl-, methioninyl- and tryptophanyldithiocarbamate and phaladtc = phenylalaninyldithiocarbamate. The structure of these complexes is probably octahedral. Molecular association through hydrogen bonding between the —NH and the carboxylate groups is proposed for the NiII complexes. The CuII complex is dimeric with the phenylalaninyldithiocarbamate acting as a bridge.

Characterization of Some New Nickel(II) Dithiolato Mixed Ligand Complexes With Nitrogen Donor Ligands: Magnetic, Spectral, and Thermal Studies

Abstract The following mixed ligand complexes were prepared and characterized: (Etdtp)2Ni (Boz)2, (Etdtp)2Ni (Btz)2, (Cydtp)2Ni (Btz)2 (Etxan)2Ni (Boz)2, (Etxan)2Ni (Btz)2, (Mexan)2Ni (morph)2, (Prxan)2Ni (morph)2, (Buxan)2Ni (morph)2, (Acac)2Co(Boz)2, (Acac)2Co(Btz)2, (Acac)2Ni(Boz)2, and (Acac)2Ni (Btz)2. Etdtp [dbnd] diethyldithiophosphate, Cydtp [dbnd] dicyclohexyldithiophosphate, Mexan [dbnd] methylxanthate, Etxan [dbnd] ethylxanthate, Prxan [dbnd] propylxanthate, Buxan [dbnd] butylxanthate, Acac [dbnd] acetylacetonate, Boz [dbnd] benzoxazole, Btz [dbnd] benzothiazole, and morph [dbnd] morpholine. The compounds were identified on the basis of their elemental analysis, IR and UV-VIS spectra, magnetic measurements, and thermal analysis.

AN INVESTIGATION OF THE Cu(II) COMPLEXES OF CERTAIN CEPHALOSPORIN ANTIBIOTICS: SPECTRAL, THERMAL, AND PHOTOCHEMICAL STUDIES

ABSTRACT The following Cu(II) complexes of some cephalosporin antibiotics were synthesized and characterized: [Cu(ATB)Cl]ċ-xH2O, [Cu(ATB)2]ċxH2O and [Cu(ATB)2]ċxH2, where HATB=cephalexin, cephapirin, cefamandole, cefuroxime or cefotaxime, H2ATB=ceftazidime and x=1–4. The stoichiometries and structures of the complexes were deduced from their elemental analyses, IR and electronic spectra and thermal decomposition. Thermal stabilities of the complexes were discussed and kinetic parameters were calculated using the Coats-Redfern and Horowitz-Metzger equations. The photochemical behaviour of the complexes was investigated. Upon irradiation, the Cu(II) complex of cefamandole underwent two competitive processes, one is photodegradation, the other is intramolecular hydrogen abstraction, as indicated from the spectral changes. The remaining studied Cu(II) complexes behave similar to their corresponding free antibiotics.

Synthesis and spectroscopic properties of anhydrotetracyclineplatinum(II)dichloride

Abstract The reaction of tetracycline with K2PtCl4 in glacial acetic acid leads to the dehydration of tetracycline to anhydrotetracycline (ahtc) which coordinates as a bidentate ligand to the PtCl2 moiety. The composition of Pt(ahtc)Cl2 is confirmed by elemental analysis and mass spectrometry. On the basis of the electronic spectra it is suggested that the coordination takes place at the A ring of ahtc while the BCD ring system is preserved as separate chromophore. It is characterized by a long-wavelength absorption and fluorescence which appear at λmax=428 and 550 nm, respectively, for the free ahtc ligand and λmax=425 and 550 nm for Pt(ahtc)Cl2.

Anionic complexes of some transition metals containing mixedβ-diketonato and alkylxanthato ligands

SummaryEleven complexes of the type K[M(acac)(Rxan)2] and K[M(TTA)2(Rxan)], where M=CoII or NiII, acac=acetylacetonate, TTA=thenoyltrifluoroacetonate, and Rxan=alkylxanthate, R=methyl-, ethyl-, propyl-, butyl-, or cyclohexyl-, have been prepared. The magnetic and spectral data indicate that the complexes are octa-hedral and that the xanthate group is attached in a bidentate fashion to the metal ions. The conductivity data are commensurate with the ionic character in the complexes. T.g.a. were made for some of the complexes.

SPECTRAL, THERMAL, AND PHOTOCHEMICAL STUDIES ON CERTAIN FIRST, SECOND, AND THIRD GENERATION CEPHALOSPORIN ANTIBIOTICS AND THEIR CD(II) COMPLEXES

ABSTRACT The reactions of six cephalosporin antibiotics with cadmium chloride afforded the corresponding Cd(II) complexes. The antibiotics are: cephalexin, cephapirin, cefamandole, cefuroxime, cefotaxime, and ceftazidime. Their Cd(II) complexes are of the general formulas Cd(ATB)ClċxH2O, Cd(ATB)2ċ-xH2O and Cd2(ATB)Cl2ċxH2O where ATB=the respective antibiotic, x=1–3. The complexes have been characterized on the basis of elemental analyses, IR, electronic and 1H NMR spectroscopy, thermal decomposition and photochemical behaviour. Thermogravimetry and derivative thermogravimetry (TG-DTG) have been used to study the stabilities and the thermal decomposition processes of the antibiotics and their Cd(II) complexes. In some cases, the decomposition steps could be correlated with the proper decomposition products, where possible activation energies and order of the decomposition reaction have been calculated from the thermal data. The photochemical behaviour of the antibiotics under investigation and their Cd(II) complexes have been studied. Cephalexin and cefamandole show similar behaviour upon irradiation with light of 298 nm, i.e., an appearance of a new band at long wavelength attributable to the formation of a photocyclization product. The Cd(II) complex of cephalexin exhibits high light sensitivity. Mechanisms of the photolysis of the free antibiotics and Cd-complexes are suggested.

Synthesis and spectroscopic properties of (oxytetracycline)tricarbonylrhenium(I) chloride

Abstract The complex (OTC)Re I (CO) 3 Cl, with OTC=oxytetracycline, has been prepared and characterized by elemental analysis, ESI–MS, IR and UV–Vis spectroscopy. The complex, which contains OTC as a bidentate ligand, shows an OTC intraligand fluorescence at λ max =570 nm with Φ =2×10 −3 at λ exc =390 nm.

Synthesis, Spectral and Thermal Studies on Cobalt(II), Copper(II), Nickel(II) and Zinc(II) Chelates with p-tolylsalicylaldimine and Some Amino Acids

Abstract New cobalt(II), copper(II), nickel(II) and zinc(II) complexes of the p-tolyIsalicylaIdimine Schiff base (sal-TH) and some amino acids have been prepared. The complexes have the general formula [M(sal-T)(aa)].nH2O where M = Co(II), Cu(II), Ni(II) and Zn(II); sal-T = monoanion of the Schiff base p-tolylsalicylaldimine; aa = monoanion of the amino acids phenylalanine (Phala), tyrosine (tyr) or methionine (met); n = 0 for M = Co(II), Cu(II) or Ni(II) and n = 2 for M = Zn(II). The complexes have been characterized and studied by elemental analyses, conductivity, IR and UV-V1S spectroscopy as well as thermogravimetry. The Cu(II) complexes have been proposed to possess a square-planar structure while the Co(II), Ni(II) and Zn(II) complexes have an octahedral structure attained by mutual intermolecular interactions among the adjacent mixed amino acid-Schiff base molecules. The thermal decomposition reaction order and activation energy have been computed by means of the Coats-Redfern and Horowitz-Metzger methods. The biological activity of selected complexes against some bacteria and fungi have been tested.

Synthesis and Antimicrobial Activity of Some New 3-Azo(P-Substituted Benzenesulphonamido-)-Bipyridyls and their Chelates

Abstract Two derivatives of drugs containing both substituted azosulphonamide and 2,2′-bipyridyl moieties have been synthesized by coupling of the appropriate p-substituted benzenesulphonyldiazonium acetate with 2, 2′-bipyridyl solution in sodium hydroxide. They form chelates with the metal ions Fe(III), Co(II), Ni(II), Cu(II) and Hg(II). The compounds and their chelates were characterised by means of elemental analysis and spectral measurements. The biological activity of the ligands and complexes was tested against a number of bacteria. The metal complexes possess higher antimicrobial activities than the ligands.