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The novel 3-phenylpyridinium hydrogensquarate (1) has been synthesized and its structure and properties are elucidated spectroscopically, thermally and structurally, using single crystal X-ray diffraction, linear-polarized solid-state IR-spectroscopy, UV-spectroscopy, TGA, DSC, DTA and ESI MS. Quantum chemical calculations were used to obtain the electronic structure, vibrational data and electronic spectrum. 3-Phenylpyridinium hydrogensquarate, crystallizes in the space group P−1 and the ions in the unit cell are joined into layers by intermolecular NH⋯O＝C(Sq) bonds with bond lengths of 2.625 and 2.626 Å, respectively. Hydrogentartarates form dimers by strong O＝COH⋯OCO interactions (2.499 Å). [Copyright &y& Elsevier]

Abstract: Structure, magnetic and optical properties of tetraphenylborate salts of 2,5-[1-methyl-4-[2-(4-hydroxyphenyl)ethenyl]piridinium]-propane and butane are performed in gas and condense phase by means of solution and solid-state conventional and linear-polarized IR-spectroscopy of oriented colloids in nematic liquid crystal suspension, UV–vis and fluorescence methods, HPLC tandem ESI mess spectrometry (MS/MS), 1H, 13C and 1H–1H COSY NMR, TGV and DSC methods. Quantum chemical DFT calculations are used for performing of the structures, optical and nonlinear optical properties of the studied compounds. [Copyright &y& Elsevier]

Abstract: Structural and spectroscopic elucidation of merocyanine dye, 2,5-[1-metyl-4-[2-(4-hydroxyphenyl)ethenyl)]piridinium]-hexane tetraphenylborate, is performed in gas and condense phase by means of solution and solid-state conventional and linear-polarized IR-spectroscopy of oriented colloids in nematic liquid crystal suspension, UV–vis and fluorescence methods, HPLC MS/MS tandem and ESI mass spectrometry, 1H, 13C and 1H–1H COSY NMR, TGV and DSC methods. Quantum chemical DFT calculations are performed for structural optimization and spectroscopic properties prediction. [Copyright &y& Elsevier]

Abstract: The linear-dichroic infrared (IR-LD) spectroscopy of oriented solid samples as suspension in nematic liquid crystal have been carried out for experimental IR-band assignment and structural information of 2-{5,5-dimethyl-3-[2-(2,4,6-trimethoxyphenyl)vinyl]cyclohex-2-enylidene} malononitrile polymorphs. The last data have been compared with known crystallographic ones, thus determining the validity of IR-LD spectral conclusions as well as its possibility to determination of Davydov''s splitting effect and separation of pairs of maxima corresponding to non-equivalent molecules included in the unit cell of given compound. The experimental structural and spectroscopic data in our case are supported with theoretical DFT ones, obtaining both the electronic structure and vibrational frequencies in gas phase. [Copyright &y& Elsevier]

Twelve new Au(III), Pt(II) and Pd(II) complexes with glycyl-containing homopeptides glycyl-glycine (G2), glycyl-glycyl-glycine (G3), glycyl-glycyl-gycyl-glycine (G4), glycyl-glycyl-glycyl-glycyl-glycine (G5) and glycyl-glycyl-glycyl-glycyl-glycyl-glycine (G6) have been synthesized, isolated and characterized spectroscopically and structurally by means of solid-state linear-dichroic infrared (IR-LD) spectroscopy of oriented colloids in nematic liquid crystal host, 1H- and 13C-NMR, TGA and DSC, UV-Vis spectroscopy, EPR, ESI- and FAB mass spectrometry and HPLC tandem mass spectrometry (HPLC-MS/MS). Quantum chemical calculations are carried out with a view to obtain the structures and spectroscopic properties of the ligand and newly synthesized metal complexes. [ABSTRACT FROM AUTHOR]

Abstract: A distortion of the aromatic character and stabilization of the imino-form as a result of the protonation of 4-dimethylaminopyridine was established by IR-, UV- and 1H NMR-spectral analysis of 4-diaminopyridinium hydrogensquarate. Quantum chemical calculations were carried out at MP2 and B3LYP levels of theory and a 6-311++G** basis set with a view to determining the changes in geometrical parameters and IR-spectroscopic characteristics resulting from Npy protonation. Linear-dichroic IR-spectroscopy coupled with the orientation techniques of solid samples as liquid crystal suspensions and melted solid polycrystalline films was applied for the identification of the IR-bands, characteristic for the structural fragments of the neutral and imino-form of the pyridine derivative. The spectral results were compared with the structure, obtained by a single crystal X-ray analysis. The salt contains dimmers of hydrogensquarate anions and Npy protonated cations of which the former are stabilized by strong intermolecular OH…O interactions (2.552Å and 143.1(2)°). The 4-diaminopyridinium cation interacts with the anion through moderate NH…O bonds (2.729Å and 165.0(0)°). Individual cations are π–π stacked with their neighbors at a distance of 3.406Å. [Copyright &y& Elsevier]

Abstract: The title compound was synthesized and characterized by single crystal X-ray diffraction and solid-state polarized IR-spectroscopy of oriented colloids in a nematic host. The compound crystallizes in the monoclinic space group P21/c and its structure consists of a 3D supramolecular network of tyrammonium cations, water and sulfate anions directed by intermolecular hydrogen bonding interactions. Two non-equivalent tyrammonium cations are observed with pseudo T and T trans configurations, respectively. The vibrational characteristics of the non-equivalent molecules are assigned using solid-state polarized IR-spectroscopy. The structural and spectroscopic data are compared with theoretical calculations at the MP2/6-31++G∗ level of theory and basis set using the tyrammonium cation heptahydrate as a model system. [Copyright &y& Elsevier]

Abstract: The novel, 1-methyl-4-[2-(4-hydroxyphenyl)ethenyl]pyridinium dihydrogenphosphate salt was synthesized and its structure and properties elucidated spectroscopically, thermally and structurally, using single crystal X-ray diffraction, linear-polarized solid-state IR spectroscopy (IR-LD), UV–vis spectroscopy, TGA, DSC, DTA and MS. The compound crystallizes in the monoclinic P21/c space group and exhibits a pseudo layer structure with molecules linked by strong OH⋯O–P intermolecular hydrogen bonds of length 2.593Å. The dihydrogenphosphate anions themselves form infinite chains through strong OH⋯O–P intermolecular hydrogen bonds of lengths 2.636 and 2.658Å. The crystallographic disorder of these systems and its effect on IR-LD spectra in the solid state are discussed. Solutions of different polarity show a significant CT band shift of up to 70nm, corresponding to a molecular first hyperpolarizability value. [Copyright &y& Elsevier]

Abstract: Counterions affect on the substructures formation in the case of the merocyanine dye, 1-methyl-4-[2-(4-hydroxyphenyl)ethenyl)]piridinium] hydrogensquarate both in gas and condense phase. Spectroscopically and structural elucidation of these aggregates have been performed, using solid-state conventional and linear-polarized IR-spectroscopy of oriented colloids as a nematic liquid crystal suspension, UV–vis spectroscopy, HPLC tandem ESI mass spectrometry, 1H and 13C NMR, TGV and DSC. Quantum chemical DFT calculations have been carried out as well. Experimental and theoretical data are compared with analogous ones of corresponding iodide salt of dye studied. [Copyright &y& Elsevier]

Abstract: Quantitative IR- and Raman spectroscopic determinations of four cephalosporin antibiotics in six solid binary mixtures have been conducted. This is a new approach for spectroscopic determination of these antibiotics, since the corresponding quantitative analysis in solution only has been reported so far. The correlation coefficient r 2 was found to be in the confidence intervals within 99.32–99.88% and 99.90–95.54% for the systems under study by using the absorption ratios of the characteristic bands at 800cm−1 and 721cm−1 present in the IR- and Raman spectra of the antibiotic compounds cephalexin, cephalotin, cephaloglycin and cephamandole, respectively. Solid-state linear dichroic infrared (IR-LD) spectral analysis of the solid mixtures was carried out in order to obtain experimental IR-spectroscopic assignment of the compounds studied. Independent high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) analysis was performed for the validation of the vibrational spectroscopic data. The application of this instrumental analytical tool for the analysis of 10 tablets of the commercial products Cefamandole and Cefalotin (Actavis) was also studied. [Copyright &y& Elsevier]

Abstract: The mononuclear Au(III)-complex ([Au(C18H18N2O4)Cl]) and hydrogensquarate ([C22H21N2O8]) of dipeptide phenylalanyltyrosine (H–Phe–Tyr–OH) have been synthezised, characterized spectroscopically and structurally by means of solid-state linear-polarized IR-spectroscopy, 1H- and 13C-NMR, ESI-MS, HPLC-MS–MS, FAB-MS, TGS and DSC methods. The structure of the Au(III)-complex has been predicted theoretically by DFT calculations. The dipeptide coordinated in a tridentate manner via –NH2, –COO− and N−-groups. One Cl− ion is attached to the metal centre as a terminal ligand, yielding a planar AuN2OCl chromophor. The hydrogensquarate consists in positive charged dipeptide moiety and negative one hydrogensquarate (HSq−) anion stabilizing by strong intermolecular hydrogen bonds. [Copyright &y& Elsevier]

Dipeptides glycyl-L-serine and L-seryl-L-tyrosine are tridentate ligands in coordination with Cu(II) through their NH2-, N-(from deprotonated amide group) and O-atom (by COO- group), forming [CuII(LH-1)H2O]. The forth position of square-planar geometry of Cu2+ is occupied by H2O as terminal ligand. Solid-state linear dichroic IR-spectroscopy, UV-Vis, mass spectrometry with ESI and FAB, tandem mass spectrometry (HPLC-MS/MS), TGV and DSC methods, EPR and magnetochemistry data prove the formation of five-membered chelate rings with participation of Cu2+ both in solution and in solid state. [ABSTRACT FROM AUTHOR]

Abstract: The novel 3,4-diaminopyridinium hydrogentartarate dihydrate has been synthesized and its structure and properties elucidated in detail spectroscopically, thermally and structurally, using single crystal X-ray diffraction, linear-polarized solid state IR-spectroscopy, UV-spectroscopy, TGA, DSC, DTA and positive and negative ESI-MS. Quantum chemical calculations were used to obtain the electronic structure, vibrational data and electronic spectra. The studied compound crystallizes in the noncentrosymmetric space group P2 1 2 1 2 1 and exhibits a 3D network with molecules linked with participation of cations, anions and solvent molecules. Hydrogentartarates form infinite chains through strong O6;OCO interaction. The effects of N1 protonation on the optical and magnetic properties of 3,4-diaminopyridine are elucidated by comparison with the data of the neutral form. [Copyright &y& Elsevier]

Abstract: Benzamidinium d-glucuronate (1) crystallizes in the orthorhombic space group P212121 and exhibits a 3D network with molecules linked by moderate intermolecular hydrogen bonds (HNH…O(solvent) 2.993Å, HNH…OCO 2.894Å, HNH…O(cycle) 2.844Å, OH…NH2 2.931Å, OH…O(solvent) 2.894, 2.924 and 2.715Å (stronger)) with participation of cations, anions and solvent molecules. The IR-band assignment of carbohydrate moieties is elucidated by a comparison between the types and bond lengths of intermolecular interactions with participation of OH groups in d-glucuronate and linear polarized IR-(IR-LD) spectroscopic data. Experimental results are supported by theoretical ab initio calculations of benzamidinium cation and d-glucuronate anion. [Copyright &y& Elsevier]

Abstract: The hydrogensquarates of alanyl-containing dipeptides glycylalanine (H-Gly-Ala-OH) and alanylalanine (H-Ala-Ala-OH) are characterized structurally by means of quantum chemical ab initio calculations, solid-state linear-dichroic infrared (IR-LD) spectroscopy, 1H and 13C NMR data, ESI-MS, HPLC-MS/MS, TGV and DSC methods. The structures consist in positive charged peptide moiety and negative hydrogensquarate anion (HSq−), stabilizing by strong intermolecular hydrogen bonds. The theoretical and IR-LD spectroscopic data are compared with corresponding ones of zwitterion dipeptides with a view to understanding the structural and conformational changes as well as the IR-spectroscopic ones as a result of hydrogensquarates formation. The strong overlapped and complicated IR-spectroscopic bands typical for hydrogensquarates in solid-state are assigned supporting with the presented vibrational analysis of the dipeptides and of the hydrogensqauarate anion. [Copyright &y& Elsevier]

Abstract: The novel squaric acid derivative, 5-amino-2-methoxypyridin ester amide of squaric acid ethyl ester with second order NLO application in solution and in the bulk has been synthesized and is structure and properties elucidated in detail spectroscopic, thermally and structurally, using single crystal X-ray diffraction, linear-polarized solid state IR-spectroscopy, UV-spectroscopy, and TGA, DSC, DTA, MS and SHG methods. Quantum chemical calculations were used for obtain in the electronic structure, vibrational data and NLO properties. At room temperature the studied compound crystallizes in the noncentrosymmetric space group C c and exhibits a pseudo-layer structure (solid phase 1) with molecules linked by NH⋯Olecular hydrogen bonds with length of 2.955Å and NH⋯O angle of 153.41°, respectively. At 200°C a phase transition is observed, with the solid phase 2 exhibiting new intermolecular NH⋯N interactions, as elucidated by IR-spectroscopy and thermal analysis. The obtained large powder SHG efficiency of 609 times urea proves the NLO application of studied compound in the bulk. [Copyright &y& Elsevier]

Abstract: Quantitative infrared (IR) and Raman spectroscopic approach for determination of phenacetin (Phen) and salophen (Salo) in binary solid mixtures with caffeine: phenacetin/caffeine (System 1) and salophen/caffeine (System 2) is presented. Absorbance ratios of 746cm−1 or 721cm−1 peaks (characteristic for each of determined compounds in the Systems 1 and 2) to 1509cm−1 and 1616cm−1 (attributed to Phen and Salo, respectively) were used. The IR spectroscopy gives confidence of 98.9% (System 1) and 98.3% (System 2), while the Raman spectroscopic data are with slightly higher confidence of 99.1% for both systems. The limits of detection for the compounds studied were 0.013 and 0.012mole fraction for IR and Raman methods, respectively. Solid-state linear dichroic infrared (IR-LD) spectral analysis of solid mixtures was carried out with a view to obtaining experimental IR spectroscopic assignment of the characteristic IR bands of both determined compounds. The orientation technique as a nematic liquid crystal suspension was used, combined with the so-called reducing-difference procedure for polarized spectra interpretation. The possibility for obtaining supramolecular stereo structural information for Phen and Salo by comparing spectroscopic and crystallographic data has also been shown. An independent high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) analysis was performed for comparison and validation of vibrational spectroscopy data. Applications to 10 tablets of commercial products APC and Sedalgin are given. [Copyright &y& Elsevier]

Abstract: l-Tyrosine-containing dipeptides valyl-tyrosine (H-Val-Tyr-OH) and tyrosyl-alanine (H-Tyr-Ala-OH) are characterized structurally by means of quantum chemical ab initio calculations and solid-state linear-dichroic infrared (IR-LD) spectroscopy. The IR-characteristic bands are assigned by application of reducing-difference procedure for polarized IR-spectra interpretation. Infrared data obtained are supported as well by the made vibrational analysis. The structures of both peptides are predicted on the basis of conformational analysis and structural information, obtained by the shown IR-spectroscopic tool. [Copyright &y& Elsevier]

Abstract: The IR-spectral characteristic bands assignment in 1700–400cm−1 IR-spectral region of l-methionine in solid-state has been carried out by means of linear-polarized IR-spectral analysis of oriented solid-samples as a suspension in nematic liquid crystal. The later results are supported by the comparison with the known single crystal X-ray data as far as the presented spectroscopic approach give possibilities not only for obtaining of the experimental IR-bands assignment but a receiving a stereo-structural information. [Copyright &y& Elsevier]

Abstract: Solid-state linear-dichroic infrared (IR-LD) spectroscopy, using an orientation technique as a suspension in nematic liquid crystal, has been carried out of Aspirin polymorphs (forms I and II). Reducing-difference procedure for polarized IR-spectra interpretation has been applied for structural analysis of both modifications and the data have been compared with known crystallographic ones. A vibration assignment of forms I and II has been included and on this basis, a quantitative determination by FT-IR spectra for form I in mixtures with second one has been presented, using intensity ratio of 1606cm−1 peak (characteristic for both forms) to 599cm−1 one (attributed to form I). The obtained reliability is 99.78%. [Copyright &y& Elsevier]

We report the synthesis, spectroscopic and structural elucidation of two prolinamide derivatives of squaric acid, i.e. prolinamide ester amide of squaric acid ethyl ester (1) and prolinamide diamide of squaric acid dihydrate (2). Both compounds crystallize in non-centrosymmetric space groups, monoclinic P21 (1) and orthorhombic P212121 (2), respectively. For first time in the literature the crystal structure of homodiamide of amino acid amide of squaric acid is reported. The data for heterodiamides is also absent. Supramolecular zig-zag chains by hydrogen bonds of H2N–C=O⋯HNH (3.020 Å) and HNH⋯O=C(Sq) (2.972 Å) types with the participation of amide and squaric acid (Sq) fragments, –C=O–NH2 and O=C(Sq) are refined in (1). A helix supramolecular structure is formed in (2) by moderate intermolecular HNH⋯O=C(NH2) hydrogen bond with length of 2.947 Å. The two crystallographical non-equivalent water molecules stabilized the helix by interactions of types HOH⋯O=C(Sq) (2.917 Å), HOH⋯O=C(NH2) (2.899 Å), H2O⋯NH2(C=O) (2.972 Å), respectively. Optical and magnetic properties are investigated with a view to explain the correlation structure-properties of the newly synthesized molecules. [Copyright &y& Elsevier]

Abstract: Two novel adducts of codeinone with barbituric and 2-thiobarbituric acids have been synthesized via Michael addition. The compounds were spectroscopically elucidated by means of IR-LD spectroscopy of oriented samples as a suspension in nematic liquid crystals, UV spectroscopy and 1H and 13C NMR spectroscopy. The 2-thiobarbituric adduct was characterized by X-ray crystallography. HPLC tandem mass spectrometry (HPLC ESI MS/MS) and thermal methods were also employed. Quantum chemical calculations have been performed with a view to obtaining the electronic structure and vibrational properties of the novel compounds. [Copyright &y& Elsevier]

Abstract: Two novel l-lysinium hydrogensquarate monohydrate (1) and the corresponding salt of the l-lysinium dication (2) are synthesized and their structure and properties elucidated in detail spectroscopically, thermally and structurally, using single crystal X-ray diffraction, linear-polarized solid-state IR-spectroscopy oriented colloid suspensions in nematic host, TGA, DSC, DTA methods, positive and negative HPLC tandem mass spectrometry (ESI-MS·MS). Quantum chemical methods are used to calculate the electronic structure, vibrational data and electronic spectra. Two novel structural motifs have been obtained, isolated [(HSq−)] and tetramolecular [(H2Sq)(HSq)2(Sq)]4− anion, respectively. Preliminary second harmonic generation measurements are also performed. [Copyright &y& Elsevier]

The article analyzes the crystal structure of the organic compound N,N-Diethyl-N'-[(E)-4-pyridylmethylene]benzene-1,4-diamine supported by combined X-ray and density functional theory structure optimization. It determines the presence of neutral molecules of a dipolar Schiff base chromophore in the structure and observes the crystallization of the compound in the noncentrosymmetric space group Pna21. Also observed is the stacking interactions in the crystal structure leading to herring-bone packing motif.