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Pregled bibliografske jedinice broj: 71816

Časopis

Autori: Rademacher, Paul; Basarić, Nikola; Kowski, Klaus; Šindler-Kulyk, Marija
Naslov: Photoelectron Spectra, Electronic Structures, and Conformational Properties of Substituted 2-Styrylpyrroles
Izvornik: European Journal of Organic Chemistry (1434-193X) - (2002), 3; 551-556
Vrsta rada: članak
Ključne riječi: Conformational analysis; Density functional calculations; Electronic Structure; Photoelectron spectroscopy
Sažetak:
The UV photoelectron spectra of three pairs of cis/trans-isomers of 2-(2-methylstyryl)pyrroles (1-6) have been recorded and analysed, making use of density functional theory (DFT) calculations at the B3LYP level. Compounds 1 and 2 have no further substituents in the pyrrole ring. In the other compounds the pyrrole ring is substituted by a methyl group in the 1-(3,4) or 5-position (5,6). Twisted conformations were calculated for 1-6 in which the toluene ring is generally much more distorted from the plane of the central C=C double bond than the pyrrole ring. In the cis-isomers (2, 4, 6) the torsion angle of the toluene groups amounts to about 50 o, while in the trans-isomers (1, 3, 5) the torsional angle is only about half as large. The energy difference delta IP values of the ionization bands associated with the molecular orbitals (MOs) pi7 and pi3 is related to torsion. Calculated delta IP values are generally 5-10 % larger than the experimental values, indicating that torsional vibrations contribute to the apparent distortion of the molecules. The results clearly indicate that PE spectroscopy - in combination with high-level quantum chemical calculations - is a verasatile method to distinguish E/Z isomers of heterocyclic stilbene-like molecules.
Projekt / tema: 0125004
Izvorni jezik: ENG
Rad je indeksiran u
bazama podataka:
Current Contents Connect (CCC)
Scopus
SCI-EXP, SSCI i/ili A&HCI
Science Citation Index Expanded (SCI-EXP) (sastavni dio Web of Science Core Collectiona)
Kategorija: Znanstveni
Znanstvena područja:
Kemija
URL cjelovitog teksta:
Google Scholar: Photoelectron Spectra, Electronic Structures, and Conformational Properties of Substituted 2-Styrylpyrroles



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