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Efekti supstituenata na 1H-NMR hemijska pomeranja 3-metilen-2-supstituisanih-1,4-pentadiena

dc.creatorValentić, Nataša
dc.creatorUšćumlić, Gordana
dc.description.abstractThe principle of linear free energy relationships was applied to the 1H chemical shifts of the β-vinyl proton atoms of 3-methylene-2-substituted-1,4-pentadienes. The correlations of the proton chemical shifts with Swain and Lupton substituent parameters provide a mutually consistent picture of the electronic effects in these compounds. The overall pattern of proton chemical shifts can be largely accounted for by a model of substituent effects based on field, resonance and ¶ polarization effects. Owing to the particular geometric arrangement of the vinyl group in 3-methylene-2-substituted-1,4-pentadienes, the β-vinyl protons HB and HC have different sensitivities to polar and resonance effects. The different sensitivities of the 1H chemical shifts to resonance effects reveals some effects not predicted by the model outlined above. Evidence is presented that demonstrates that both the 1H and 13C chemical shifts for these compounds reflect their ground-state charge densities.en
dc.description.abstractNa 1H hemijska pomeranja β-vinil-protona u 3-metilen-2-supstituisanim-1,4-pentadienima je primenjen princip linearne korelacije slobodnih energija. Korelacije protonskih hemijskih pomeranja sa supstituentskim parametrima Swain-a i Lupton-a pružaju usaglašenu sliku elektronskih efekata u ovim jedinjenjima. Sveukupni koncept hemijskih pomeranja protona u velikoj se meri može objasniti modelom efekata supstituenata zasnovanih na efektima polja, rezonancionim i ¶ polarizacionim efektima. U skladu sa posebnim geometrijskim rasporedom vinil-grupe u 3-metilen-2-supstituisanim-1,4-pentadienima, β-vinil protoni HB i HC imaju različitu osetljivost na polarne i rezonancione efekte. Različita osetljivost 1H hemijskih pomeranja na rezonancione efekte otkriva nepoznati efekat koji nije predviđen pomenutim modelom. Pokazano je da 1H i 13C hemijska pomeranja za ova jedinjenja odražavaju elektronske gustine osnovnog
dc.publisherSerbian Chemical Society, Belgrade
dc.sourceJournal of the Serbian Chemical Society
dc.subjectcross-conjugated trienesen
dc.subjectring substituted α-(s-cis-2-butadienyl)styrenesen
dc.subjectβ-vinyl proton chemical shiftsen
dc.subjectsubstituent effectsen
dc.titleEffects of substituents on the 1H-NMR chemical shifts of 3-methylene-2-substituted-1, 4-pentadienesen
dc.titleEfekti supstituenata na 1H-NMR hemijska pomeranja 3-metilen-2-supstituisanih-1,4-pentadienasr
dc.citation.other68(7): 525-534

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