carboethoxymethyl)-3phthalimidopropylammonium chloride N,N-dimethyl(carboxymethyl)-3phthalimidopropylammonium hydrochloride Intermolecular hydrogen bonds DFT calculations FTIR and NMR spectra a b s t r a c t N,N-dimethyl(carboethoxymethyl)-3-phthalimidopropylammonium chloride dihydrate (1) and N,Ndimethyl(carboxymethyl)-3-phthalimidopropylammonium hydrochloride (3) have been obtained in reaction of N,N-dimethyl-3-phthalimidopropylamine with ethyl chloroacetate and chloroacetic acid, respectively. N,N-dimethyl(carboethoxymethyl)-3-phthalimido-propylammonium chloride dihydrate (1) has been characterized by FTIR and NMR spectroscopy. Moreover, for (1) and (3) B3LYP calculations have been carried out. The optimized bond lengths, bond angles and torsion angles calculated by B3LYP/ 6-31G(d,p) approach have been presented. Both FTIR and Raman spectra of (1) are consistent with the calculated structures in the gas phase. Correlations between the experimental 1 H and 13 C NMR chemical shifts (d exp ) of investigated compound in D 2 O, and the GIAO/B3LYP/6-31G(d,p) calculated magnetic isotropic shielding tensors (r calc ), d exp = a + b r calc , are reported. The assignments of the anharmonic experimental solid state vibrational frequencies of (1) based on the calculated B3LYP/6-31G(d,p) harmonic frequencies have been made. Linear correlations between the experimental 1 H and 13 C chemical shifts and the computed screening constants confirm the optimized geometry.