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Infrared Fingerprints of n(N) -> sigma*(NH) Hyperconjugation in Hydrazides

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Autor(es):
Andrade, Laize A. F. ; Silla, Josue M. ; Cormanich, Rodrigo A. ; Freitas, Matheus P.
Número total de Autores: 4
Tipo de documento: Artigo Científico
Fonte: Journal of Organic Chemistry; v. 82, n. 23, p. 7-pg., 2017-12-01.
Resumo

An earlier study demonstrated that hyperconjugation operates in hydrazides by analyzing the N-H stretching mode in gas phase infrared (IR) spectroscopy, and then observing two very distinct bands corresponding to isolated isomers experiencing or not the n(N) -> sigma*(N-H) electron delocalization. The present work reports a chemical method to obtain insight on the hyperconjugation in hydraiide derivatives from solution IR spectroscopy. The analogous amides did not show a v(N-H) red-shifted band, as the electron donor orbital in the above hyperconjugative interaction does not exist. In addition, the effect of electron withdrawing groups bonded to a nitrogen atom, namely the trifluoroacetyl and the methanesulfonyl groups, was analyzed on the conformational isomerism and on the ability to induce a stronger hyperconjugation in the resulting compounds. (AU)

Processo FAPESP: 17/02364-0 - Investigações mecanísticas da reação de Biginelli, utilizando-se abordagens experimentais e teóricas
Beneficiário:Rodrigo Antonio Cormanich
Modalidade de apoio: Bolsas no Exterior - Pesquisa