Artículos de revistas
Molecular structure, experimental and theoretical 1H and 13C NMR chemical shift assignment of cyclic and acyclic α,β-unsaturated esters
Date
2014-01Registration in:
Jios, Jorge Luis; Duddeck, Helmunt; Buceta, Norma Nelida; Autino, Juan Carlos; Ruiz, Diego Manuel; Romanelli, Gustavo Pablo; et al.; Molecular structure, experimental and theoretical 1H and 13C NMR chemical shift assignment of cyclic and acyclic α,β-unsaturated esters; John Wiley & Sons Ltd; Journal Of Physical Organic Chemistry; 27; 2; 1-2014; 106-113
0894-3230
CONICET Digital
CONICET
Author
Buceta, Norma Nelida
Ruiz, Diego Manuel
Romanelli, Gustavo Pablo
Autino, Juan Carlos
Duddeck, Helmunt
Pis Diez, Reinaldo
Jios, Jorge Luis
Abstract
The experimental 1H and 13C NMR spectra of 13 phenyl cinnamates and four 4-methylcoumarins were investigated and their chemical shifts assigned on the basis of the two-dimensional spectra. For the unsubstituted cinnamic acid phenyl ester, optimized molecular structures were calculated at a B3LYP/6-311++G(d,p) level of theory. 1H and 13C NMR chemical shifts were also calculated with the GIAO method at the B3LYP/6-311 + G(2d,p) level of theory. The comparison between experimental and calculated NMR chemical shift suggests that the experimental spectra are formed from the superposition spectra of the two lowest energy conformers of the compound in solution. The most stable s-cis configuration found in our studies is also the conformation adopted for a related phenyl cinnamate in solid state. The experimental results were analyzed in terms of the substituent effects.