Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 117 (1986), S. 51-54 
    ISSN: 1434-4475
    Keywords: Ion-pair charge-transfer ; Main component analysis ; Solvent effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Solvent effects on the position of ion-pair charge-transfer absorption bands are described using a three parameter approach. The values of calculated coefficients are discussed considering specific and non-specific interactions.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1434-1948
    Keywords: Copper chelates ; EPR spectroscopy ; Electronic structure ; Schiff base ligands ; Structure elucidation ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of tetrahedrally distorted copper(II) complexes with thiolate and imine coordination were synthesized. Schiff bases derived from 4-benzoyl-3-methyl-1-phenyl-2-pyrazoline-5-thione and various diamines were used as tetradentate ligands to obtain tetrahedrally distorted metal chelates with [CuN2S2] complex units. Crystal structures of the complexes 1, 2, 5 and 6 and of ligand H25 have been determined by means of single-crystal X-ray structure analysis. The structure data show a strong influence of the diamine building blocks on the tetrahedral distortion of the copper(II) complexes. Results of Extended Hückel LCAO calculations correlate strongly with structural, electrochemical, UV/Vis- and EPR-spectroscopic features obtained experimentally. The calculations confirm for the whole complex series a strong delocalization of the frontier orbitals. The highest fully occupied molecular orbital shows a weak contribution, resulting from thiolate donor atoms, whereas the antibonding singly occupied molecular orbitals (SOMOs) are distributed between the copper(II) centre (ca. 35-40%) and the N2S2 donor set. The SOMO energy significantly lowers with increasing tetrahedral distortion of the coordination sphere. The influence of the tetrahedral distortion of copper(II) complexes on redox potentials, UV/Vis and EPR spectra is discussed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Calculation of the CoIII/Low Spin CoII Reduction Potentials of Selected Amine and Diimine ComplexesThe electrochemical reduction potentials of amine and diimine CoII complexes, respectively, refer to the transition from CoIII (t2g6) to high-spin CoII (t2g5eg2). On the contrary, light-induced electron transfer from the anion to CoIII within ion pairs distinguished by second-sphere charge-transfer (SSCT) behavior leads always to low-spin CoII (t2g6eg1) in the first step. The energies of the thermally equilibrated 2E states have been determined for six CoII complexes and the appropriate low-spin reduction potentials have been derived. The differences between the electrochemical and the calculated low-spin potentials are in the rang between 0.1 and 0.8 volts. Ion pairs from CoIII complexes and iodide ions are distinguished by a linear relationship between the absorption maxima of the SSCT bands and the appropriate low-spin reduction potentials, as it is to be expected from CANNONS model.
    Notes: Für Cobalt(III)-Komplexe mit Amin- und Diiminiliganden bezieht sich das elektrochemisch ermittelte Reduktionspotential auf den Übergang von CoIII (t2g6) nach high-spin CoII (t2g5eg2). Dagegen wird in Ionenpaaren mit Second-Sphere Charge-Transfer (SSCT) Verhalten bei der lichtinduzierten Elektronenübertragung vom Anion zum Cobalt(III)-Komplex zunächst low-spin CoII (t2g6eg1) gebildet. Für 6 Cobalt(II)-Komplexe wurde die Energie des thermisch äquilibrierten 2E-Terms berechnet und daraus das low-spin Reduktionspotential abgeleitet. Die Unterschiede zwischen den elektrochemisch ermittelten high-spin Potentialen und den low-spin Potentialen betragen zwischen 0,1 und 0,8 V. Die Energien der SSCT-Absorptionsmaxima der Ionenpaare von Cobalt(III)-Komplexen mit Iodid stehen mit den low-spin Reduktionspotentialen der Komplexe in dem nach dem CANNON-Modell erwarteten linearen Zusammenhang.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 829-840 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Increment System for Predicting of the Position of Ion Pair Charge-Transfer Bands in Water and Non-aqueous SolventsThe energy of the absorption maximum of ion-pair charge-transfer bands, ΔGCT, occuring in addition to the absorptions of the single ions, is approximately the sum of contributions (increments) of the ions concerned. On the basis of spectroscopic data, an increment system for predicting of ΔGCT in aqueous solution has been proposed. A linear relationship between the increments and the standard electrode potentials of ions has been found, permitting the expansion of the increment system. The difference between calculated and experimental values does not exceed 2500 cm-1. The applicability of the increment system to non-aqueous solvents has been proved in several cases.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...