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1

Solid-State Spectroscopic and Structural Elucidation of L-Phenylalanyl-L-alanine Dihydrate and Its Hydrochloride

Zareva S., Kolev T., Tchapkanov A., Spiteller M., Koleva B.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 3

421-430

EN

Correlation structure/IR-spectroscopic properties of the dipeptide L-phenylalanyl-Lalanine dihydrate (H-Phe-Ala-OHź2H2O) and its hydrochloride (H-Phe-Ala-OHźHCl) in solid-state is elucidated by means of the linear-polarized IR- (IR-LD) spectroscopy of oriented colloid suspension in nematic host. The IR-spectroscopic and structural assignment obtained by the polarization tool is compared with known crystallographic data of H-Phe-Ala-OHź2H2O. The characterization of the hydrochloride salt is supported in addition by the HPLC tandem ESI mass spectrometry (MS/MS), 1H- and 13C-NMR, TGA and DSC methods. Quantum chemical calculations are performed with a view to obtain electronic structure and vibrational properties of both neutral and protonated dipeptide, thus completing the experimental assignment.

2

Crystal structure and spectroscopic properties of 4-acetaminopyridine and its protonated form

Koleva B.B., Nikolova R., Tchapkanov A., Kolev T., Mayer-Figge H., Spiteller M., Sheldrick W.S.

Polish Journal of Chemical Technology

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2009

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Vol. 11, nr 3

35-40

EN

4-Acetaminopyridine dihydrate and its protonated form, stabilized as the hydrochloride salt have been synthesized and spectroscopic elucidated in solution and in the solid-state by means of the inear-polarized solid state IR-spectroscopy (IR-LD), UV-spectroscopy, TGA, DSC, and the positive and negative ESI MS. Quantum chemical calculations were used to obtain the electronic structure, vibrational data and the electronic spectra. The spectroscopic and theoretical data are compared with the structure of the first compound obtained by single crystal X-ray diffraction. The effect of Npy protonation on the optical and magnetic properties of a 4-acetaminopyridine is discussed.

3

Structural Elucidation, Optical and Magnetic Properties of Tetraphenylborate Salt of 2,5-[1-Methyl-4-[2-(4-hydroxyphenyl)ethenyl)]pyridinium]-butane

Stoyanov S., Koleva B. B., Kolev T., Petkov I., Spiteller M.

Polish Journal of Chemistry

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2008

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Vol. 82, nr 11

2167-2178

EN

Structure, magnetic and optical properties of tetraphenylborate salt of 2,5-[1-methyl-4-[2-(4-hydroxyphenyl)ethenyl)]pyridinium]-hexane were performed for condensed phase by means of solution and solid-state conventional and linear-polarized IR-spectroscopy of oriented colloids in nematic host, UV-Vis and fluorescence methods, HPLC MS-MS tandem and ESI mass spectrometry, 1H-, 13C- and 1H-1H COSY NMR, TGV and DSC methods. Electronic structure and vibrational analysis were carried out by quantum chemical calculations at two levels of theory second-order Moller-Plesset perturbation theory (MP2) and density functional theory (DFT) using 6-31G* basis set. B3LYP method, which combines Becke's three-parameter non-local exchange functional with the correlation function of Lee, Yang and Parr, was applied.