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  • 1H-NMR Relaxivity  (1)
  • Copper, nickel complexes of N-acyl-thiourea derivatives  (1)
  • Gold complexes  (1)
  • 1
    ISSN: 0044-2313
    Keywords: Gold complexes ; preparation ; crystal structures ; ab initio Hartree-Fock calculations ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Dimeric Gold Selenolates: Preparation and Characterization of [(n-C4H9)4N]2[AuSSeC = C(CN)2]2 and [(n-C4H9)4N]2[AuSe2C = C(CN)2]2The preparation and structural characterization of the dimeric AuI complexes of 1,1-dicyanoethene-2,2-thioseleonlate (i-mnts) and 1,1-dicyanoethene-2,2-diselenolate (i-mns), isolated as Bu4N salts, are described. They are isotype (monoclinic, space group P21/c, Z = 2) with lattice parameters: (Bu4N)2[Au(i-mnts)]2; a = 14.078(3) Å, b = 8.912(3) Å, c = 20.142(4) Å, β = 106.32(5)°; (Bu4N)2[Au(i-mns)]2; a = 13.998(3) Å, b = 9.125(3) Å, c = 20.039(2) Å, β = 105.12(5)°. Ab initio Hartree-Fock calculations based on the experimentally determined structure yield a positive value of the Au—Au bonding order suggesting weak bonding interactions between the d10 metal centres.
    Notes: Die Darstellung und Strukturaufklärung der als Bu4N-Salze (Bu = n-C4H9) isolierten dimeren AuI-Komplexe des 1,1-Dicyanoethen-2,2-thioselenolats (i-mnts) und des 1,1-Dicyanoethen-2,2-diselenolats (i-mns) werden beschrieben. Sie kristallisieren zueinander isotyp (monoklin, Raumgruppe P21/c, Z = 2) mit folgenden Gitterkonstanten: (Bu4N)2[Au(i-mnts)]2; a = 14,078(3) Å, b = 8,912(3) Å, c = 20,142(4) Å β = 106,32(5)°; (Bu4N)2[Au(i-mns)]2; a = 13,998(3) Å, b = 9,125(3) Å, c = 20,039(2) Å, β = 105,12(5)°. Ab-initio-Hartree-Fock-Rechnungen unter Zugrundelegung der experimentell bestimmten Geometrie mit Kristallfeldsimulation liefern einen positiven Wert der Au—Au-Bindungsordnung, der darauf hindeutet, daß der kurze Au—Au-Abstand (2,810(1) äR) auf schwache bindende Wechselwirkungen zwischen den d10-Metallzentren zurückgeführt werden kann.
    Additional Material: 1 Ill.
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  • 2
    ISSN: 0044-2313
    Keywords: Chelates, Gadolinium(III) ; Stability Constants ; 1H-NMR Relaxivity ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chelate Formation of N-Tris(2-aminoethyl)amine-N′,N′,N″,N″,N‴,N‴-hexaacetic Acid (H6TTAHA) and N-(Pyrid-2-yl-methyl)ethylenediamine-N,N′,N′-triacetic Acid (H3PEDTA) with Gadolinium(III) - Syntheses, Stability Constants, and NMR-RelaxivitiesThe chelate formation of N-tris(2-aminoethyl)amine-N′,N′,N″,N″,N‴,N‴-hexaacetic acid (H6TTAHA) and N-(pyrid-2-yl-methyl)ethylenediamine-N,N′,N′-triacetic acid (H3PEDTA) with gadolinium(III) has been studied potentiometrically in aqueous solution at 25°C and μ = 0.1 (KCl). [Gd(TTAHA)]3-: 1gβM/ML = 19.0; {H[Gd(TTAHA)]}2-: 1gKH/MHL = 8.30; [Gd(PEDTA)]: 1gβM/ML = 15.56. Both 1 : 1 gadolinium(III) complexes were isolated as Na2H[Gd(C18H24N4O12)] · 3.5 H2O and [Gd(C14H16N3O6)] · 3 H2O, respectively. Their 1H-NMR relaxivities [1 · mmol-1 · s-1] ({H[Gd(TTAHA)]}2-: 9.5; [Gd(PEDTA)]: 8.8) offer promising applications for 1H-NMR imaging.
    Notes: Die Komplexbildung von N-Tris(2-aminoethyl)amin-N′,N′,N″,N″,N‴,N‴-hexaessigsäure (H6TTAHA) und N-(Pyrid-2-yl-methyl)ethylendiamin-N,N′,N′-triessigsäure (H3PEDTA) mit Gadolinium(III) wurde in wässeriger Lösung bei 25°C und μ = 0,1 (KCl) potentiometrisch untersucht. [Gd(TTAHA)]3-: 1gβM/ML = 19,0; {H[Gd(TTAHA)]}2-: 1gKH/MHL = 8,30; [Gd(PEDTA)]: 1gβM/ML = 15,56. Die 1 : 1-Gadolinium(III)-Komplexe wurden im Fall der H6TTAHA als Dinatriumsalz Na2H[Gd(C18H24N4O12)] · 3,5 H2O, bei der H3PEDTA als Neutralkomplex [Gd(C14H16N3O6)] · 3 H2O erhalten. Ihre NMR-Protonenrelaxivitäten [1 · mmol-1 · s-1] ({H[Gd(TTAHA)]}2-; 9,5; [Gd(PEDTA)]: 8,8) eröffnen Anwendungen als Kontrastmittel für die Kernspintomographie.
    Additional Material: 3 Ill.
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  • 3
    ISSN: 0044-2313
    Keywords: Copper, nickel complexes of N-acyl-thiourea derivatives ; acid dissociation constants ; complex stability constants ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hydrophilic Substituted N-Acyl-thioureas  -  Acidity and Stability of Complexes in Dioxane/Water MixturesSome derivatives of N-acyl-thioureas containing hydroxy, ester or sulfonic acid groups as well as their copper(II) and nickel(II) complexes have been synthesized. Acid dissociation constants and complex stability constants have been measured pH-potentiometrically in dioxane/water mixtures ranging from 75 to 0% (v/v) dioxane involving main group and subgroup metal ions as well. The partially remarkable changes of the constants in varied solvent mixtures are discussed.
    Notes: Eine Reihe N-Acyl-thioharnstoffe mit Hydroxy-, Ester- oder Sulfonsäuregruppen und ihre Kupfer(II)- und Nickel(II)-Komplexe wurden erstmals synthetisiert und ihre Säuredissoziationskonstanten pH-potentiometrisch in Dioxan/Wassergemischen (Dioxangehalt 75 - 0 Vol.-%) bestimmt. Die Stabilitätskonstanten der Komplexe mit 1-, 2- und 3-wertigen Metallionen aus Haupt- und Nebengruppen des PSE wurden ebenfalls ermittelt. Die z. T. drastischen Veränderungen der Konstanten bei Variation der Lösungsmittelzusammensetzung werden diskutiert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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