摘要:
Eighteen aliphatic linear amines, from methylamine to stearylamine, have been experimentally studied by NMR and theoretically calculated at the GIAO/B3LYP/6-311++G(d,p) level. A partial exploration of their conformation has been carried out, mainly to determine the effect on the chemical shifts. In solution and for neutral amines, N-15 chemical shifts indicate a mixture of two conformations. In the solid state (CPMAS NMR) only the subset of solid amines has been studied (from C14 to C18). The N-15 signals of the corresponding ammonium salts in the solid state depend on the counteranions, Cl- and CF3CO2-, a result that is theoretically proven. (C) 2011 Elsevier Ltd. All rights reserved.