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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]

Correlation between the structure and IR-spectroscopic properties of two halogen and one amino substituted esters of coumarin-3-phosphonic acid has been studied by means of linear-polarized IR-spectroscopy of oriented colloid suspensions in nematic host. The influence of the ester group on the peak positions of the IR-characteristic bands of these derivatives and in particular, on phosphorus group is investigated by a comparison with the data for corresponding coumarin-3-phosphonic acids. Theoretical quantum chemical DFT calculations (B3LYP/6-311++G**) are carried out, thus supporting the experimental assignment of the IR-bands and predicting the electronic structure of all of the compounds studied. [ABSTRACT FROM AUTHOR]

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]

The components of the title compound, C6H14N+·C4HO4-·- 0.5H2O, are connected by moderate intermolecular N—H⋯O hydrogen bonds between the anions and cations into infinite three-dimensional networks. The cyclohexylammonium cation interacts with the solvent molecule by means of an N—H⋯O hydrogen bond. The hydrogensquarate anions form α chains through strong O—H⋯O interactions. [ABSTRACT FROM AUTHOR]

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.

The title compound, C16H9NO4, also known as the 3-benzoylpyridinium betaine of squaric acid, exhibits a dipolar electronic ground-state structure with a positively charged pyridinium fragment and a negatively charged squarate moiety. In the molecule, the two aromatic rings are twisted by 56.03 (2)° relative to one another. The three-dimensional packing of the molecules is stabilized by C—H··O· short contacts. [ABSTRACT FROM AUTHOR]

Molecules of syring­aldehyde, C9H10O4, are connected by intermolecular O—H⋯O [H⋯O = 2.05 Å and O⋯O = 2.713 (2) Å] hydrogen bonds between the 4-hydroxy and 1-aldehyde functions into infinite linear chains. The 4-hydroxy H atoms also participate in an intramolecular O—H⋯O [H⋯O = 2.22 Å and O⋯O = 2.662 (2) Å] interaction with a neighbouring methoxy O atom. [ABSTRACT FROM AUTHOR]

In the title compound, C11H10N+·C4H5O6−·2H2O, hydrogen tartrate anions and water molecules are linked by strong O—H...O hydrogen bonds to form corrugated layers. The 4-phenylpyridinium cation decorates the layer from both sides, being hydrogen bonded to the water molecule only. The three-dimensional packing of the complex layers is accomplished by strong π–π interactions of 3.668 (2) Å between the centroids of the benzyl and pyridine rings related by the symmetry operator ( x −  , − y +  , − z). [ABSTRACT FROM AUTHOR]

Mol­ecules of the title compound, 2-(2-eth­oxy-3,4-dioxocyclo­butenylamino)-2-[2-(methyl­sulfan­yl)eth­yl]acetamide, C11H16N2O4S, are connected into chains in the [010] direction by inter­molecular N—H⋯O hydrogen bonds involving thel-methio­ninamide N atoms and its carbonyl O atom. [ABSTRACT FROM AUTHOR]

Mol­ecules of the title compound, C9H11NO, are connected into infinite chains by inter­molecular N—H⋯O hydrogen bonds of length 2.893 (3) Å between the N-methyl­amino and carbonyl functions. [ABSTRACT FROM AUTHOR]