Artykuły naukowe (WCh)
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Browsing Artykuły naukowe (WCh) by Author "Barczyński, Piotr"
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Item Molecular structure of 8-hydroxy-1-methylquinolinium iodide hydrate in crystal and solution(2006-06-29) Barczyński, Piotr; Komasa, Anna; Ratajczak-Sitarz, Małgorzata; Katrusiak, Andrzej; Brzezinski, Bogumil8-Hydroxy-1-methylquinolinium iodide monohydrate [(C10H10NO)I-+(-) H2O] has been studied by X-ray diffraction, FF-IR, H-1 and C-13 NMR spectroscopy. In the crystalline state, the iodide anion is hydrogen-bonded to the water molecule, which in turn is hydrogen bonded to the 8-OH group of the 8-hydroxyquinolinium ring, forming of a symmetric dimer. In acetonitrile and DMSO-d(6) the hydrate assumes a new structure due to almost complete dissociation of the water molecule from the complex structure. In acetonitrile the 8-OH group is hydrogen-bonded to the iodide anion, whereas in DMSO-d(6) it forms the hydrogen bond with the solvent molecules. This 8-OH... O(DMSO-d(6)) hydrogen bond is the strongest within the structure of the hydrate.Item Molecular structure, hydrogen bonding and spectroscopic properties of the complex of piperidine-4-carboxylic acid with chloroacetic acid(2008-10-29) Komasa, Anna; Katrusiak, Andrzej; Szafran, Mirosław; Barczyński, Piotr; Dega-Szafran, ZofiaComplex of piperidine-4-carboxylic acid with chloroacetic acid has been studied by X-ray diffraction, FTIR, Raman, H-1 and C-13 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)center dot center dot center dot O(3) of 2.604(2) angstrom, N(1)-H(12)center dot center dot center dot O(3) of 2.753(2) angstrom and N(1)-H(11)center dot center dot center dot O(4) of 2.760(2) angstrom. 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 center dot center dot center dot N(1) of 2.658 angstrom and the second with carboxyl group, O(1)-H center dot center dot center dot O(3) of 2.860 angstrom. In water solution piperidine-4-carboxylic acid is protonated and forms two hydrogen bonds with the chloroacetate unit: N(1)-H center dot center dot center dot O(4) of 2.690 angstrom and O(1)-H center dot center dot center dot O(3) of 2.611 angstrom. Powder FTIR spectra of the complex and its deuterated analogue are consistent with the X-ray structure. Correlations between the experimental H-1 and C-13 chemical shifts of the complex investigated and the GIAO/B3LYP/6-31G(d,p) calculated magnetic isotropic shielding tensors (sigma(calc)) in vacuum and within the conductor-like screening continuum solvation model (COSMO) in H2O, delta(exp) = a + b sigma(calc), are reported.