Artículos de revistas
Solvent effects in the (2)J(HH), (3)J(HH), (1)J(NC) and (2)J(NC) coupling constants in the NMR spectrum of acetylcholine chloride
Registro en:
Journal Of Molecular Structure. Elsevier Science Bv, v. 797, n. 41699, n. 44, n. 48, 2006.
0022-2860
WOS:000241544100006
10.1016/j.molstruc.2006.03.012
Autor
Sega, EM
Tormena, CF
de Oliveira, PR
Rittner, R
Tinoco, LW
Figueroa-Villar, JD
Hoehr, NF
Institución
Resumen
Coupling constant values (J(NH) and J(NC)) obtained from H-1 and C-13 NMR spectra of acetylcholine chloride (ACh) in several solvents with a wide range of permittivity constants (epsilon) are remarkably invariant, indicating the absence of solvent effects in the conformational equilibrium of this compound. The values show that the OCH2CH2N+ system occurs in a gauche arrangement. J(NH) and J(NC) are observable in most solvents, but not in chlorine-containing solvents, and are not dependent on solvent viscosity. This behavior was explained using data from T-1 measurements. The measurement of NMR diffusion coefficients shows that ACh has a greater tendency to aggregate when dissolved in chlorinated solvents, a fact that could explain the observed differences in N-14 T-1. (c) 2006 Elsevier B.V. All rights reserved. 797 41699 44 48