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Spectroscopic CNDO /CI study of some cyclic polyenes
Author(s) -
Zuccarello Felice,
Buemi Giuseppe,
Raudino Antonio
Publication year - 1980
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.540010405
Subject(s) - cndo/2 , cyclooctatetraene , spectral line , chemistry , computational chemistry , space (punctuation) , cycloheptatriene , range (aeronautics) , physics , crystallography , atomic physics , stereochemistry , quantum mechanics , molecule , materials science , organic chemistry , linguistics , philosophy , composite material
CNDO/ S calculations are carried out on 1,3,5‐cycloheptatriene (I), 1,3,5,7‐cyclooctatetraene (II), all‐ cis ‐1,3,5,7‐cyclononatetraene (III), and all‐ cis ‐1,4,7‐cyclononatriene (IV), for which π‐σ separability is a questionable matter. When disparate choices are available for the geometries, preferences are based on the agreement between calculated and experimental spectra. The microwave structure for I and an unsymmetrical conformation for III are suggested. In the electronic spectra, conjugative contributions are assigned to the lowest‐energy weak band, while an ethylenic nature is to be attributed to the intense band in the range of 6 eV. The possibility of through‐space π interactions is examined qualitatively. An appreciable degree of such interaction is shown by IV.