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A Circular Dichroism Study of Molecular Association of Cinchona Alkaloids and Carboxylic Acids

J. Gawronski ; Faculty of Chemistry, A. Mickiewicz University, 60-780 Poznan, Poland
M. Brzostowska ; Faculty of Chemistry, A. Mickiewicz University, 60-780 Poznan, Poland
J. Koput ; Faculty of Chemistry, A. Mickiewicz University, 60-780 Poznan, Poland

Puni tekst: engleski, pdf (5 MB) str. 97-107 preuzimanja: 146* citiraj
APA 6th Edition
Gawronski, J., Brzostowska, M. i Koput, J. (1989). A Circular Dichroism Study of Molecular Association of Cinchona Alkaloids and Carboxylic Acids. Croatica Chemica Acta, 62 (2A), 97-107. Preuzeto s https://hrcak.srce.hr/175384
MLA 8th Edition
Gawronski, J., et al. "A Circular Dichroism Study of Molecular Association of Cinchona Alkaloids and Carboxylic Acids." Croatica Chemica Acta, vol. 62, br. 2A, 1989, str. 97-107. https://hrcak.srce.hr/175384. Citirano 30.09.2020.
Chicago 17th Edition
Gawronski, J., M. Brzostowska i J. Koput. "A Circular Dichroism Study of Molecular Association of Cinchona Alkaloids and Carboxylic Acids." Croatica Chemica Acta 62, br. 2A (1989): 97-107. https://hrcak.srce.hr/175384
Harvard
Gawronski, J., Brzostowska, M., i Koput, J. (1989). 'A Circular Dichroism Study of Molecular Association of Cinchona Alkaloids and Carboxylic Acids', Croatica Chemica Acta, 62(2A), str. 97-107. Preuzeto s: https://hrcak.srce.hr/175384 (Datum pristupa: 30.09.2020.)
Vancouver
Gawronski J, Brzostowska M, Koput J. A Circular Dichroism Study of Molecular Association of Cinchona Alkaloids and Carboxylic Acids. Croatica Chemica Acta [Internet]. 1989 [pristupljeno 30.09.2020.];62(2A):97-107. Dostupno na: https://hrcak.srce.hr/175384
IEEE
J. Gawronski, M. Brzostowska i J. Koput, "A Circular Dichroism Study of Molecular Association of Cinchona Alkaloids and Carboxylic Acids", Croatica Chemica Acta, vol.62, br. 2A, str. 97-107, 1989. [Online]. Dostupno na: https://hrcak.srce.hr/175384. [Citirano: 30.09.2020.]

Sažetak
Circular dichroism (CD) spectra of cinchona alkaloids and their salts with carboxylic acids have been investigated. A eontributionof the exciton type Cotton effect to the 230 nm CD band of free bases in non-polar solvents is suggested to result from the association of alkaloid molecules. Strong association is observed in the case of dihydrocupreidine - an alkaloid with free phenolic group.
Comparison of the CD spectra of salts of alkaloids with
mono- and dicarboxylic acids demonstrates that in the latter case
the p-band Cotton effects originate from the exciton type interactions
between the associated molecules.
The unusual rotations of salts of cinchona alkaloids with
biphenyl 1,1'-dicarboxylic acids have been found to originate
from the strong intermolecular exciton coupling, rather than from
the »first-order asymmetric transformation«. The existence of the
two low energy staggered conformations around the C(8)-C(9)
bond in the alkaloid molecule has been confirmed by the MMP2
calculation on a model compound.

Hrčak ID: 175384

URI
https://hrcak.srce.hr/175384

Posjeta: 233 *