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Abstract: A discussion on the possible application of the organic 5-sulfosalicylates as organic materials with tunable optical and non-linear-optical (NLO) properties is performed on the basis of the experimental crystallographic and spectroscopic methods such as single crystal X-ray diffraction, electronic absorption, diffuse reflectance and fluorescence spectroscopy in condense phase, conventional and linear-polarized IR- and Raman spectroscopy in solid-state. The model systems 5-sulfosalicylic acid dihydrate (1), 4-aminobenzamidinium bis(5-sulfosalicylicilate) monohydrate (2) and 5-sulfosalicylicilate salt of glycinamide (3), comparing with the as well as theoretical quantum chemical calculations of the systems neutral 5-sulfosalicylic acid (I), its mono-(Ia) and dianion (Ib), respectively. [Copyright &y& Elsevier]

Abstract: Possibilities of linear-dichroic infrared (IR-LD) spectroscopy based on oriented solid samples as suspension in nematic liquid crystal have been applied for detailed experimental IR-band assignment and structural information of 2-[5,5-dimethyl-3-(2-phenyl-vinil)-cyclohex-2-enylidene]-malononitrile, 2-[5,5-dimethyl-3-[2-(2-methoxyphenyl)vinyl]cyclo-hex-2-enylidene]malononitrile and 2-[3-[2-(2,4-dimethoxyphenyl)vinyl]-5,5-dimethylcyclohex-2-enylidene]malononitrile. The data of last two compounds have been compared with known crystallographic ones, thus determining the validity of conclusions made. [Copyright &y& Elsevier]

Abstract: Stereo structural characterization of methionine-containing tripeptides glycine-glycine-methionine (Gly-Gly-Met) and methionine-glycine-glycine (Met-Gly-Gly) is carried out by means of linear-dichroic infrared spectral analysis of oriented as nematic liquid crystal suspension solid samples. Thus obtained data are compared with theoretical ones received by ab initio calculations (Hartree-Fock level of theory and 6-31G** basis set). An IR-spectral characterization of both tripeptides is included as well. [Copyright &y& Elsevier]

Abstract: Validation of reducing-difference procedure based on subtracting of non-polarized infrared (IR) spectra of n-component solid mixtures is presented. The accuracy and precision are established. The limits of detection are 3.0, 2.5, 1.5 and 1.0wt.% for 5-, 4-, 3-and 2-component mixtures, respectively. Smoothing procedures for IR spectral analysis, based on Savitzky–Golay or Fourier methods are applied as well. The mean values and relative standard deviations for peak position (ν i ) and integral absorbance (A i ) obtained by this data processing approach have been examined using Student''s t-test. [Copyright &y& Elsevier]

Abstract: By means of solid-state linear-dichroic infrared (IR-LD) spectroscopy the stereo-structures of dipeptides methionyl-histidine (Met-His) and histidyl-methionine (His-Met) are predicted, accompanied with a detailed experimental IR-characteristic bands assignment. The experimental results are compared and confirmed with theoretical structural ones, obtained by ab initio calculations at the Hartree–Fock level of theory and 6-31G**. [Copyright &y& Elsevier]

Interaction between the S-Phe–S-Phe dipeptide (PP) and Au(III) leads to the formation of a yellow complex, [Au(PP)Cl3]Cl (1), with monodentate coordination of the dipeptide with Au(III) through one O atom of the COO - group. Three Cl - anions bond to the metal center as terminal ligands. The structure of 1 was obtained by comparative solid-state linear-dichroic infrared (LD-IR) spectroscopic analysis of a solid sample and the pure dipeptide S-Phe–S-Phe, both oriented in a nematic liquid crystal suspension. [ABSTRACT FROM AUTHOR]

Abstract: Solid-state linear dichroic infrared (IR-LD) spectral analysis of both monoclinic (form I) and orthorhombic (form II) polymorphs of paracetamol was carried out using an orientation technique as a nematic liquid crystal suspension. The so-called reducing-difference procedure for polarized spectra interpretation was applied and the obtained supramolecular stereo structural data of both modifications were compared with known crystallographic ones. A detailed vibration assignment of characteristic frequencies of forms I and II was also applied. A quantitative FT-IR spectral approach for monoclinic form determination in mixtures by the intensity ratio of 1610cm-1 peak (characteristic for both forms) to 1666cm-1 one (attributed to orthorhombic modification) was presented, as well. [Copyright &y& Elsevier]

Abstract: A linear dichroic infrared (IR-LD) spectral analysis of solid 4-aminopyridine (4-AP) samples was carried out using two orientation techniques, i.e., as polycrystalline layers and in a nematic mesophase. The so-called reducing-difference procedure was used for the polarized IR-spectra interpretation. By achieving a more precise assignment of a part of the 4-AP characteristic frequencies, the obtained data proved a Fermi-resonance splitting of the symmetrical NH2-stretch and confirmed the predominant aromatic character of the pyridine ring. The possibilities of the difference IR-LD technique used for the study of the supramolecular solid-state structure are also illustrated. [Copyright &y& Elsevier]