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  • 1
    Electronic Resource
    Electronic Resource
    Structural Studies of Cu(II) Chelates with Some Arylidene Derivatives of Benzilic Hydrazide (1998)
    Springer
    Monatshefte für Chemie 129 (1998), S. 19-29 
    Details
    ISSN: 1434-4475
    Keywords: Keywords. Copper chelates; Hydrazones; Benzilic hydrazides.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung.  Die Cu(II)-Chelate einiger neuer Arylidenderivate des Benzilsäurehydrazids wurden synthetisiert und mittels Elementaranalyse, Thermogravimetrie und Differentialthermoanalyse sowie IR-, UV/Vis-, ESR- und Röntgenspektroskopie untersucht. Die erhaltenen Daten zeigen, daβ tetraedrische 1:1- und quadratisch-planare 2:1- und 1:2-Komplexe gebildet werden. In den 1:1-Komplexen verhalten sich die organischen Verbindungen wie dibasische dreizähnige Liganden, während sie in den 1:2- und 2:1-Komplexen in monobasischer zweizähniger Form vorliegen.
    Notes: Summary.  The Cu(II) chelates of some new arylidene derivatives of benzilic hydrazide have been synthesized and were characterized by elemental and thermal analyses, as well as by IR, UV/Vis, ESR, and X-ray spectroscopy. The data revealed the formation of tetrahedral 1:1 (L :M) and square planar 2:1 and 1:2 complexes. In the 1:1 complexes, the organic compounds behave as dibasic tridentate ligands towards the Cu(II) ion, whereas in the 1:2 or 2:1 complexes they behave as monobasic bidentate substituents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00010100
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  • 2
    Electronic Resource
    Electronic Resource
    Structural studies on 3-acetyl-1,5-diaryl and 3-cyano-1,5-diaryl formazan chelates with cerium(III), thorium(IV) and uranium(VI) (1993)
    Springer
    Monatshefte für Chemie 124 (1993), S. 627-635 
    Details
    ISSN: 1434-4475
    Keywords: Complexes of 3-acetyl and 3-cyano formazans ; Ce(III) ; Th(IV) ; U(VI)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die hergestellten Chelate wurden mittels Elementaranalyse, IR, NMR, TGA und DTA charakterisiert. Darauf basierend wird die generelle Formel [M(HL) m (OH−) n bzw. (NO 3 − oder Cl−) x ·(H2O) y oder (C2H5OH bzw.DMSO) z ] vorgeschlagen, wobei HL=Formazan,M=Ce3+, Th4+ oder UO 2 2+ ,m=1–2,n=0–3,x=0–3,y=0–4 undz=0–3. Die Metallionen haben Koordinationszahlen von 6–8.
    Notes: Summary Solid complexes of 3-acetyl-1,5-diaryl and 3-cyano-1,5-diaryl formazans were prepared and characterized by elemental analysis, IR, NMR, TGA and DTA analyses. Based on these studies, the suggested general formula for the complexes is [M(HL) m (OH−) n or (NO 3 − or Cl−) x ·(H2O) y or (C2H5OH orDMSO) z , where HL=formazanM=Ce3+, Th4+, and UO 2 2+ ,m=1–2,n=0–3,x=0–3,y=0–4 andz=0–3. The metal ions are expected to have coordination numbers 6–8.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00817298
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  • 3
    Electronic Resource
    Electronic Resource
    Chelation behaviour of lanthanides with somethio-Schiff bases (1995)
    Springer
    Monatshefte für Chemie 126 (1995), S. 163-171 
    Details
    ISSN: 1434-4475
    Keywords: Stability constants ; Lanthanides ; Potentiometry ; Conductometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Stabilitätskonstanten von Komplexen trivalenter Y-, La-, Ce-, Pr-, Sm-, Gd-, Dy-, Ho-, Er- und Yb-Ionen mit einigenthio-Schiffschen Basen wurden potentiometrisch unter Verwendung der vonIrving undRossotti modifiziertenCalvin-Bjerrum-Titrationstechnik bei 25 °C undI=0.1M (NaCl) in 70% (v/v) wäßrigem Ethanol bestimmt. Wie konduktometrisch gezeigt werden konnte, treten 1:1- und 1:2-Komplexe auf. DiepK a -Werte der SH-Gruppen wurden mit denHammetschen Substituentenkonstanten korreliert, die Stabilitätskonstanten mit den Kernladungszahlen der Lanthaniden und mit der Summe der Ionisationskonstanten der Liganden.
    Notes: Summary The stability constants of complexes of trivalent Y, La, Ce, Pr, Sm, Gd, Dy, Ho, Er, and Yb ions with somethio-Schiff bases have been determined potentiometrically using theCalvin-Bjerrum titration technique as modified byIrving andRossotti at 25 °C and an ionic strength of 0.1M (NaCl) in 70% (v/v) aqueous ethanol. 1:1 and 1:2 complexes are formed and evidenced by conductometric studies. ThepK a values of the SH group were correlated with theHammet constants of substituents. The values of the stability constants are correlated with the atomic numbers of the lanthanides and with the sum of the ionization constants of the ligands.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00812245
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  • 4
    Electronic Resource
    Electronic Resource
    Spectrophotometric studies on complexes of Co(II), Ni(II) and Cu(II) with benzimidazolylazo derivatives (1979)
    Springer
    Microchimica acta 72 (1979), S. 501-506 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Zwei neue Farbreagenzien, 2-(4-Benzimidazolylazo)-R-Säure (I) und 5-(4-Benzimidazolylazo)-8-hydroxychinolin (II), wurden dargestellt. Die Zusammensetzung, die Stabilitätskonstanten und die optimalen Bedingungen für die Bildung der Komplexe von Co(II), Ni(II) und Cu(II) mit I und II wurden untersucht. Komplexe der Zusammensetzung 1∶1 und 1∶2 (M∶L) werden mit Ausnahme von Cu(I) gebildet, das nur einen 1∶2-Komplex bildet. Ein rasches Verfahren zur spektrophotometrischen Bestimmung von Co(II), Ni(II) und Cu(II) mit I und II wurde ausgearbeitet. Beide Reagenzien können als Indikatoren für die Titration der drei Metalle mit ÄDTA verwendet werden.
    Notes: Summary Two new chromophoric reagents, 2-(4-benzimidazolylazo)-R-acid (I) and 5-(4-benzimidazolylazo)-8-hydroxyquinoline (II) have been prepared. The composition, stability constants and optimal formation conditions of the complexes of Co2+, Ni2+ and Cu2+ with I and II have been studied, 1∶1 and 1∶2 (M∶L) complexes being formed in all cases except for the Cu-I complex, only the 1∶2 complex being formed. A rapid method for the spectrophotometric determination of Co2+, Ni2+ and Cu2+ with I and II has been developed. Both reagents can be used as indicators for EDTA titration of the three metal ions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01198511
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  • 5
    Electronic Resource
    Electronic Resource
    Spectrophotometric microdetermination of uranium with m- and p-carboxyphenylazo-chromotropic acid (1976)
    Springer
    Microchimica acta 65 (1976), S. 451-455 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Eine spektrophotometrische Methode zur Bestimmung von Uran mit Hilfe vonm-bzw.p-Carboxyphenylazochromotropsäure wurde beschrieben. Die besten Arbeitsbedingungen für die Bildung der beiden Komplexe wurden angegeben. Die Zusammensetzung entspricht dem Verhältnis 1 ∶ 1 bzw. 1 ∶ 2 von Uran zurm-bzw. zurp-Verbindung. Das Beer'sche Gesetz ist für die Bereiche 2–16 bzw. 2–18 ppm Uran im Falle derm-bzw. derp- Verbindung erfüllt.
    Notes: Summary A simple and rapid method for the spectrophotometric determination of uranium usingm- andp-carboxyphenylazo-chromotropic acid is given. The optimum conditions favouring the formation of the two complexes are reported. The molecular structure was found to be 1 ∶ 1 and 1 ∶ 2 of uranium to them- or thep-compound. Beer's law is obeyed for the ranges 2–16 and 2–18 ppm of uranium in the case of them- andp- compound respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01218276
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  • 6
    Electronic Resource
    Electronic Resource
    Determination of silicon using electrothermal Zeeman atomic absorption spectrometry in presence of some transition metals as modifiers (1998)
    Springer
    Fresenius' journal of analytical chemistry 360 (1998), S. 650-653 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The transition metals ions Cr(III), Mn(II), Fe(III), Co(II), Ni(II), and Zn(II) in addition to Ca(II) have been used as modifiers in the determination of silicon using electrothermal Zeeman atomic absorption spectrometry. Co(II) proved to be the best. Graphite tubes treated with zirconium, in the presence of Co(II) as a modifier, exhibit higher sensitivity by a factor of five than untreated tubes. The modifier concentration and ashing and atomization temperatures have been optimized. Also interference of different inorganic cations and anions was studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050774
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  • 7
    Electronic Resource
    Electronic Resource
    Electrical conductivity, electronic absorption, IR and NMR studies on some ethyl cyanoacetate phenylhydrazones and their lanthanide complexes (1997)
    Springer
    Journal of thermal analysis and calorimetry 48 (1997), S. 851-863 
    Details
    ISSN: 1572-8943
    Keywords: activation energy ; electrical conductivity ; hydrazones ; Ln(III) complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The electrical conductivities and the electronic, IR and NMR spectra were measured for some ethyl cyanoacetate phenylhydrazone derivatives and their lanthanide complexes in the temperature range 20–200
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01997190
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  • 8
    Electronic Resource
    Electronic Resource
    Thermodynamic Parameters of Some Schiff Bases Derived From 5,7-dihydroxy-6-formyl-2-methylbenzopyran-4-one (2000)
    Springer
    Journal of thermal analysis and calorimetry 59 (2000), S. 913-926 
    Details
    ISSN: 1572-8943
    Keywords: benzopyran-4-one ; chromone ; ionic strength ; potentiometry ; Schiff bases ; temperature and solvent
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Potentiometric studies on Schiff bases derived from5,7-dihydroxy-6-formyl-2-methylbenzopyran- 4-one were carried out at different ionic strengths (0.02, 0.04, 0.06, 0.10 and 0.14 M NaCl), at different temperatures (25, 35, 45 and55°C) and in ethanol-water media of varying compositions (60, 70, 80 and 90% v/v). The ionization constants of the Schiff bases were investigated in the presence of different organic solvents (70% v/v), e.g. methanol, ethanol, n-propanol, isopropanol, acetone, DMSO and DMF-water media. The thermodynamic parameters (ΔG, ΔH and ΔS) were also calculated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010182527146
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  • 9
    Electronic Resource
    Electronic Resource
    Electrical, spectral and thermochromic properties of some hydrazone derivatives (1994)
    Springer
    Journal of materials science 5 (1994), S. 199-202 
    Details
    ISSN: 1573-482X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The electrical and spectral properties of some ethyl cyanoacetate phenylhydrazone derivatives have been investigated. Results obtained show anomalous metallic-like and semiconducting behaviours corresponding to the low and higher temperature ranges. At high temperatures a positive temperature coefficient of electrical conductivity (dΣ/dT) provides evidence for the semiconducting character, and the linear correlation indicates metallic-like behaviour at a low temperature range. Values of activation energy (δE) were calculated in each case. In addition, the current-voltage dependence of the hydrazone derivatives was investigated. This showed that the compounds under study have ohmic conduction. The correlation between γmax and Σa Hammett constant was also investigated. The hydrazone derivatives are thermolabile and undergo thermochromic behaviour during heating.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00186185
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  • 10
    Electronic Resource
    Electronic Resource
    Electrical and spectrophotometric properties of charge transfer complexes of picric acid and some aniline derivatives (1993)
    Springer
    Journal of materials science 4 (1993), S. 109-112 
    Details
    ISSN: 1573-482X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The charge transfer complexes produced by the reaction between picric acid and some aniline derivatives were prepared. The prepared charge transfer complexes (CTC) were investigated using infrared and nuclear magnetic resonance spectroscopy aiming to throw more light on their molecular structure. It was proved that a proton transfer interaction takes place between PiOH and x-Ph.NH2 leading to the formation of PiO} and x-Ph.NH3 + ions. The normal π-π1 electronic interaction takes place by transferring an electron from the aniline ring to the picric acid. The semiconducting properties of the CTC were investigated. All the prepared complexes were proved to have a semiconducting character within the temperature range investigated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00180464
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