A. Komasa, A. Katrusiak, M. Szafran
Oct 29, 2008
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Influential Citations
8
Citations
Journal
Journal of Molecular Structure
Abstract
Abstract Complex of piperidine-4-carboxylic acid with chloroacetic acid has been studied by X-ray diffraction, FTIR, Raman, 1H and 13C NMR spectroscopy and B3LYP/6-31G(d,p) calculations. In crystal the piperidine ring is protonated and adopts a chair conformation with the COOH group in the equatorial position. The COO− group of chloroacetate unit is engaged in three hydrogen bonds: O(1)–H(1)···O(3) of 2.604(2) A, N(1)–H(12)···O(3) of 2.753(2) A and N(1)–H(11)···O(4) of 2.760(2) A. According to the B3LYP calculations the isolated complexes both in vacuum and H2O solution have cyclic structures. In vacuum the molecules are connected by two H-bonds: the COOH group of chloroacetic acid is engaged with piperidine-4-carboxylic acid, one with the nitrogen atom, O(4)–H···N(1) of 2.658 A and the second with carboxyl group, O(1)–H···O(3) of 2.860 A. In water solution piperidine-4-carboxylic acid is protonated and forms two hydrogen bonds with the chloroacetate unit: N(1)–H···O(4) of 2.690 A and O(1)–H···O(3) of 2.611 A. Powder FTIR spectra of the complex and its deuterated analogue are consistent with the X-ray structure. Correlations between the experimental 1H and 13C chemical shifts of the complex investigated and the GIAO/B3LYP/6-31G(d,p) calculated magnetic isotropic shielding tensors (σcalc) in vacuum and within the conductor-like screening continuum solvation model (COSMO) in H2O, δexp = a + b σcalc, are reported.