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  • 1
    ISSN: 1434-4475
    Keywords: Complex formation constant ; Conductance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wurden die Co(II)-, Ni(II)- und Cu(II)-Komplexe einiger bifunktioneller Aryliden-o-phenylendiamin-Schiffbasen hergestellt. Unter Verwendung elektronenspektroskopischer Methoden wurde die Bildung, Stöchiometrie und Stabilität der Komplexe in Lösung untersucht. Die Charakterisierung erfolgte mittels Elementaranalysen, Leitfähigkeitsmessungen und Elektronen- bzw. IR-Spektroskopie. Es wird darauf geschlossen, daß daso,o-HydroxyderivatL 1 als bivalenter vierzähniger ONNO Ligand wirkt, während die anderen Derivate (L 2-L 5) als zweizähnige NN Liganden an die Metallionen koordiniert sind. Für den Cu(II)-L 1 Komplex wird eine tetraedrische Geometrie vorgeschlagen, währenddessen die anderen Komplexe eine verzerrte octaedrische Geometrie aufweisen. Die in den Elektronenspektren der Komplexe inDMF-Lösung auftretenden Banden werden den π-π*,L →M CT und d-d Elektronenübergängen zugeordnet.
    Notes: Abstract Co(II), Ni(II) and Cu(II) complexes of some bifunctional arylidene-o-phenylenediamineSchiff bases have been prepared. Formation, stoichiometry and stability of the complexes have been tested in solution using electronic spectral measurements. Characterization of the complexes has been accomplished primarily by elemental analysis, molar conductance as well as electronic and IR spectral measurements. It is concluded that theo,o-hydroxy derivative (L 1) acts as a bivalent ONNO tetradentate ligand while the molecules of the other derivatives (L 2-L 5) are coordinated to the metal ions as bidentate NN ligands. The Cu(II)-L 1 complex is suggested to possess a tetrahedral geometry whereas the other complexes are suggested to exhibit a distarted octahedral geometry. The different bands observed in the electronic spectra of the complexes inDMF solutions have been assigned to the π-π*,L →M CT and d-d electronic transitions.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 129 (1998), S. 625-632 
    ISSN: 1434-4475
    Keywords: Keywords. Convolutive cyclic voltammetry; Chronopotentiometry; Digital simulation; Kinetic parameters; Experimental voltammograms.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung.  Die Reaktion von Chlorid an einer Glaskohlenstoffelektrode (GCE) in 0.1 M Tetrabutylammoniumperchlorat (TBAP)/Dichlormethan (CH2Cl2) und seine elektrochemischen Kenngrößen wurden mittels konvolutiver cyclischer Voltammetrie und Chronopotentiometrie (CP) untersucht. Die experimentellen Ergebnisse wurden durch Vergleich der Voltammogramme mit simulierten Daten überprüft. Konvolutive cyclische Voltammetrie zeigt hohe Empfindlichkeit und ist bezüglich der Auflösung der konventionellen cyclischen Voltammetrie überlegen.
    Notes: Summary.  The electrode reaction of chloride at a glassy carbon electrode (GCE) in 0.1 M tetrabutylammoniumperchlorate (TBAP)/dichloromethane (CH2Cl2) and its electrochemical parameters were determined via convolutive cyclic voltammetry and chronopotentiometric (CP) techniques. The parameters calculated from experimental data were tested by comparing the experimental voltammograms with the simulated data. Convolutive cyclic voltammetry was found to provide high sensitivity and better resolution than ordinary cyclic voltammetry.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 130 (1999), S. 525-535 
    ISSN: 1434-4475
    Keywords: Keywords. Ruthenium-carborane complexes; Hexamethylbenzene; para-Cymene; Cyclic voltammetry; Digital simulation.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung.  Rutheniumkomplexe einiger Carborane wurden mit Hilfe zyklischer Voltammetrie, Chronoamperometrie, Chronopotentiometrie und digitaler Simulationstechniken im Zusammenhang mit Konvolutions-Dekonvolutions-Voltammetrie untersucht. Die Komplexe sind vom Typ X-RuC2B8H10 (X=Hexamethylbenzol oder Paracumol). Alle relevanten elektrochemischen und chemischen Parameter wurden abgeleitet; ein Reaktionsmechanismus wird vorgeschlagen.
    Notes: Summary.  Ruthenium complexes of some carboranes were examined using cyclic voltammetry, chronoamperometry, chronopotentiometry, and digital simulation techniques derived from convolution-deconvolution voltammetry. The complexes under consideration are of the type X-RuC2B8H10 (X=hexamethylbenzene, para-cymene); all relevant electrochemical and chemical parameters were deduced and a mechanism is proposed.
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  • 4
    ISSN: 1434-4475
    Keywords: Coordination compounds ; Azoimidazole ; Transition metals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wurden einige Komplexe von 4,5-Diphenylimidazol-azo-Derivaten mit den 3 d-Übergangsmetallen Co(II), Ni(II) und Cu(II) isoliert und mittels chemischer Analyse, Leitfähigkeitsmessungen und den Elektronen- bzw. IR-Spektren charakterisiert. Diese Farbstoffe zeigen eine sehr starke Tendenz zur Komplexbildung, wobei die neutralen Moleküle als zweizähnige Liganden an das Metallion koordinieren. Die Formeln für die 1:1- und 1:2-Komplexe werden mit [MLX 2(H2O)2] und [ML 2 X 2] bzw. [ML 2 X 2]·2H2O vorgeschlagen (X=Cl− oder NO 3 − ). Die verschiedenen Absorptionsbanden in den VIS-Spektren in methanolischer Lösung werden den möglichen e-Übergängen (L →MCT und d-d) zugeordnet. Für die Komplexe werden verzerrte oktaedrische Geometrien vorgeschlagen.
    Notes: Abstract The 3d transition metalion [Co(II), Ni(II) and Cu(II)] complexes of some 4,5-diphenylimidazole azo derivatives have been isolated and characterized by chemical analysis, conductance, electronic and IR spectra. These dyes are characterized by a high tendency towards complex formation with the neutral molecules coordinated to the metal ion as bidentate ligands. The molecular formula of the 1:1 and 1:2 complexes are suggested to be [MLX 2(H2O)2] and [ML 2 X 2] or [ML 2 X 2]·2H2O respectively, whereX=Cl− or NO3. the different bands observed in the visible spectra of methanolic solutions of the complexes have been assigned to the possible electronic transition type (L →MCT and d-d). It is suggested that the complexes studied have a distorted octahedral geometry.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 118 (1987), S. 589-594 
    ISSN: 1434-4475
    Keywords: Synergism ; Dithioles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wurde die synergistische Extraktion von Kobalt(II)-Komplexen mit Toluol-3,4-dithiol (TDT) in Gegenwart von Monobenzylamin (BA), Dibenzylamin (DBA) und Tribenzylamin (TBA) untersucht. Aus den Extraktionsdaten wurden die Stöchiometrien der Addukte abgeleitet. Die Werte der Bildungskonstanten (B ex) in Gegenwart der Aminliganden wurden bestimmt. Dabei ergab sich für das Extraktionsvermögen eine absteigende ReiheDBA ≫TBA〉BA.
    Notes: Abstract The synergistic extraction of cobalt(II) complexes with toluene-3,4-dithiol (TDT) in presence of monobenzylamine (BA), dibenzylamine (DBA) and tribenzylamine (TBA) has been investigated. The stoichiometry of the adducts formed was established from the extraction data. Values of the formation constant,B ex, in presence of the amine ligands have been determined. It is found that the extraction ability decreases in the orderDBA ≫TBA〉BA.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Applied microbiology and biotechnology 25 (1987), S. 327-333 
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Linamarase from Fusarium equiseti was purified 56-fold by ammonium sulphate fractionation, gel filtration on sephadex G-150 and ion-exchange chromatography on DEAE-sephadex A-50-120. The enzyme has Kms of 0.36 mM and 0.51 mM with respect to the artifical substrate, p-nitrophenyl-β-d-glucoside and its natural substrate, linamarin, respectively. γ-Gluconolactone is a strong competitive inhibitor of the enzyme with Ki of 0.2 mM when p-nitrophenyl-β-d-glucoside is the substrate. The pH optimum of the enzyme is 6.0 and further analysis indicates that the carboxyl of aspartate or glutamate, imidazole of histidine and the sulphhydryl group of cysteine may be involved in enzyme catalysis. The F. equiseti linamarase is significantly inhibited by such thiol-group reagents as iodoacetate, p-hydroxymercuribenzoate and iodosobenzoate indicating that sulphhydryl group may be present at the active site of the enzyme. The enzyme is stable up to 45°C which corresponds approximately with the optimum temperature of the linamarase-catalysed hydrolysis whose Ea was found to be 8.21 kcal/mole.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Transition metal chemistry 9 (1984), S. 199-202 
    ISSN: 1572-901X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The extraction of iron(III) and cobalt(II) from hydrochloric acid solutions by Hyamine 1622, a quaternary ammonium halide, in dichloroethane is described. The effect of acidity, salting-out agent, metal and extradant concentrations and temperature, has been investigated. The extraction mechanism is discussed in the light of results obtained. Separation of iron(III) and cobalt(II) is also outlined.
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  • 8
    ISSN: 1573-1561
    Keywords: Allelopathy ; gamma irradiation ; Sorghum bicolor ; Amaranthus retroflexus ; nitrification ; biological control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The effect of low doses of gamma irradiation on the allelopathic potential ofSorghum bicolor against weeds and nitrification was investigated. The results revealed that all test doses (500, 1000 and 1500 rad) significantly increased the allelopathic activity of root exudates, aqueous extracts, and decaying residues aganst seed germination and seedling growth ofAmaranthus retroflexus. The results also indicated that all test doses stimulated the allelopathic potential of aqueous extracts and decaying residues against nitrification activity. The possible application of this approach in biological control is briefly discussed.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 8 (1982), S. 1011-1023 
    ISSN: 1573-1561
    Keywords: Allelopathy ; inhibitors ; phenols ; glycosides ; Chenopodium album ; Rhizobium ; Azotobacter ; Cynodon dactylon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In earlier work, we found thatPolygonum aviculare had pronounced allelopathic effects against several test species. Four inhibitors were isolated from livingPolygonum plants, three of which were glucosides. Four different inhibitors were isolated fromPolygonum residues and soil underPolygonum stands, and none of these occurred in soil fromCynodon dactylon (L.) Pers. stands. Three of these were glycosides containing both fructose and cellobiose as the sugars. Color reactions of all the inhibitors indicated that they are phenolic in nature. All the inhibitors reduced seed germination and/or seedling growth ofChenopodium album L. Moreover some of them inhibited growth of different strains ofRhizobium andAzotobacter.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Environmental monitoring and assessment 16 (1991), S. 75-84 
    ISSN: 1573-2959
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Enormous amounts of seawater are desalted everyday worldwide. The total world production of fresh water from the sea is about 2621 mgd (9.92 million m3 day-1 1985 figures). Desalting processes are normally associated with the rejection of high concentration waste brine from the plant itself or from the pretreatment units as well as during the cleaning period. In thermal processes, mainly multistage flash (MSF) thermal pollution occurs. These pollutants increase the seawater temperature, salinity, water current and turbidity. They also harm the marine environment, causing fish to migrate while enhancing the presence of algae, nematods and tiny molluscus. Sometimes micro-elements and toxic materials appear in the discharged brine. This paper will discuss the impact of the effluents from the desalination plants on the seawater environment with particular reference to the Saudi desalination plants, since they account for about 50% of the world desalination capacity.
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