Structure and spectroscopic studies of 2,3-diethoxycarbonyl-1-methylpyridinium nitrate

Abstract The structure of 2,3-diethoxycarbonyl-1-methylpyridinium nitrate ( 1 ) has been studied by X-ray diffraction, DFT calculations, FTIR, Raman and NMR spectra. The crystals are monoclinic, space group C 2/ c . Nitrate anion interacts electrostatically with the positively charged pyridinium nitrogen atom. In crystals the ethyl ester group at C(3) position (C(9) O(4) CH 2 CH 3 ) is disordered in two orientations. The structures optimized by the B3LYP/6-311++G(d, p) 2 (in vacuum) and 3 (in CHCl 3 solution) are similar to that in crystal 1 . Linear correlations between the experimental 13 C and 1 H chemical shifts ( δ exp ) of the investigated ester in CDCl 3 and GIAO/B3LYP/6-311++G(d, p) magnetic isotropic shielding constants calculated by using the screening solvation model (COSMO), δ exp  =  a  +  b  ·  σ calc , are reported. The FTIR and Raman spectra of the solid compound are consistent with the X-ray structure.