Transitions with intramolecular charge transfer in the electronic absorption spectra of 8-azasteroid compounds

1990 ◽  
Vol 52 (6) ◽  
pp. 620-625
Author(s):  
V. Z. Kurbako
1969 ◽  
Vol 23 (3) ◽  
pp. 254-256 ◽  
Author(s):  
A. Mustafa ◽  
R. Abu-Eittah ◽  
S. Elgendi

The electronic absorption spectra of some drugs derived from p-amino benzoic acid were studied. The effect of the substituent on the position of band maxima and intensity has been rationalized. Long wavelength energies have been found to agree well with calculated energies of the intramolecular charge transfer bands.


1980 ◽  
Vol 35 (10) ◽  
pp. 1013-1019 ◽  
Author(s):  
Friedrich Seitz ◽  
Terence E. Wood ◽  
Peter Day

Abstract Electronic absorption spectra are reported for single crystals of composition FexCo1-xCl2 as a function of temperature from 300 K to 4 K. A broad band at 436 nm is assigned to Fe (II) → Co (II) charge transfer and the temperature dependence of its intensity is related to the magnetic exchange between the ions. The 2T1g(2H) excitation of Co (II) in the mixed crystals has an unusual temperature dependence which correlates with the Néel temperature.


1977 ◽  
Vol 55 (21) ◽  
pp. 3712-3716 ◽  
Author(s):  
Kim Doan Truong ◽  
André D. Bandrauk

Two new solid TCNQ complexes have been isolated, coronene–TCNQ 1:1 and 3:1. The infrared and electronic absorption spectra are presented for the two different stoichiometries. From these spectra we infer that the complexes are covalent in the ground state with a charge transfer band appearing at 730 nm. The out of plane vibrations of the individual molecules are noticeably perturbed upon complexation.


1979 ◽  
Vol 35 (11) ◽  
pp. 1229-1234
Author(s):  
A.J. Mālmanis ◽  
Ya.A. Eiduss ◽  
J.F. Freimanis ◽  
J.J. Drēǧeris

1982 ◽  
Vol 60 (7) ◽  
pp. 862-871 ◽  
Author(s):  
Jean-Paul Canselier ◽  
Serge Domenech ◽  
Štefan Stankovsky ◽  
Sabine Gautier

As with benzenoid donors, the electronic absorption spectra of the molecular complexes of simple or condensed sulfur or oxygen-containing five-membered heterocycles with TCNE (or DDQ) often show two charge-transfer bands. In many cases, the knowledge of the actual frequencies requires a technique of resolution. The results so obtained are correlated with the ionization potentials of donors on the one hand, and the refractivity of nonpolar solvents on the other hand.


2012 ◽  
Vol 16 (05n06) ◽  
pp. 695-704 ◽  
Author(s):  
Abraham Alemayehu ◽  
Marrigje M. Conradie ◽  
Abhik Ghosh

The Soret maxima of copper triarylcorroles are exquisitely sensitive to substitutions on the meso phenyl groups. Similar substituent effects are also known, in more muted form, for Mn and Fe corroles. In contrast, the Soret maxima Ag , CrO and MoO triarylcorroles are essentially invariant with respect to phenyl-group substituents. TDDFT calculations suggest that the unique substituent sensitivity in the copper case results from phenyl-to- Cu (dx2-y2) charge transfer character in the main peaks of the Soret region. To probe the phenonmenon in even greater depth, we have examined here the electrochemistry and electronic absorption spectra of a series of copper trans-A2B-triarylcorrole complexes, where the para substituents on the aryl groups include CF3 , H , CH3 , and OCH3 . Although both 5,15- and 10-substituents appear to influence the oxidation and reduction potentials of the copper corroles in a simple, additive manner, they affect the Soret maxima very differently. Thus, for a given 10-substituent, 5,15-aryl substituents exert a strong, "normal" substituent effect on the Soret maximum. For given 5,15-substituents, however, the 10-substituent has almost no effect on the Soret maximum. An attempt has been made to relate these somewhat curious observations to a molecular orbital picture based on copper triphenylcorrole.


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