Naslov
Synthesis, photochemistry, and photophysics of butadiene derivatives: influence of the methyl group on the molecular structure and photoinduced behavior

Autori
Škorić, Irena ; Kikaš, Ilijana ; Kovács, Margit ; Fodor, Lajos ; Marinić, Željko ; Molčanov, Krešimir ; Kojić-Prodić, Biserka ; Horváth, Ottó

Izvornik
Journal of organic chemistry (0022-3263) 76 (2011), 21; 8641-8657

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
butadienes ; spectroscopy ; reaction mechanism ; photochemistry ; photophysics ; synthesis

Sažetak
Novel butadiene derivatives display diverse photochemistry and photophysics. Excitation of 2- methyl-1-(o-vinylphenyl)-4-phenylbutadiene leads to the dihydronaphthalene derivative, while photolysis of the corresponding model o-methyl analogue results in the formation of the naphthalene-like derivative, deviating from the non-methylated analogue of the prior starting compound producing benzobi- and -tricyclic compounds. The effect of the methyl substituents is even more dramatic in the case of the dibutadienes. The parent unsubstituted compound undergoes photoinduced intramolecular cycloaddition giving benzobicyclo[3.2.1]octadiene, while the photochemical reaction of the corresponding dimethylated derivative shows only geometrical isomerization due to the steric effect of the substituents. Methyl groups on the butadiene backbones reduce the extent of conjugation, causing a blue-shift of the characteristic absorption band. The fluorescence efficiency is dramatically decreased, as a consequence of non-planarity and reduced rigidity of the molecules due to the crowding by the methyl and phenyl groups together. Four molecules of very similar structures show dramatically different photoinduced behavior, revealing how changes of the nature and position of the substituents are valuable in understanding the photophysics and photochemistry of these types of compounds.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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