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1,1,1-Trichloro-3-(1-phenethylamino-ethylidene)-pentane-2,4-dione is spectroscopically and structurally elucidated by means of linear-polarized IR spectroscopy (IR-LD) of oriented solids as a colloidal suspension in nematic liquid crystal. Structural information and IR-spectroscopic assignment are supported by quantum chemical calculations at MP2 and B3LYP level of theory and 6-311++G** basis set. The geometry is characterized with an inramolecular hydrogen bond of NH...O&dbond;C with length of 2.526 Å and a NHO angle of 140.5(1)°. The NH&bond;C(CH3)C&dbond;C&bond;C&dbond;O(CH3) fragment is nearly flat with a maximal deviation of total planarity of 10.4°. Copyright © 2007 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

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 potential energy surface of curcumin [1,7‐bis(4‐hydroxy‐3‐methoxyphenyl)‐1,6‐heptadiene‐3,5‐dione] was explored with the DFT correlation functional B3LYP method using 6‐311G* basis. The single‐point calculations were performed at levels up to B3LYP/6‐311++G**//B3LYP/6‐311G*. All isomers were located and relative energies determined. According to the calculation the planar enol form is more stable than the nonplanar diketo form. The results of the optimized molecular structure are presented and compared with the experimental X‐ray diffraction. In addition, harmonic vibrational frequencies of the molecule were evaluated theoretically using B3LYP density functional methods. The computed vibrational frequencies were used to determine the types of molecular motions associated with each of the experimental bands observed. Our vibrational data show that in both the solid state and in all studied solutions curcumin exists in the enol form. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 [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 article presents information on the structure of codeinone. Codeinone has been found to possess antitumor potential, with high cytotoxic activity against human promyelocytic leukaemic cell lines and is known that codeinone in the living cell is produced from the reaction of codeine with nicotinamide adenine dinucleotide phosphate. The molecular structure exhibits features typical for morphine derivatives, with a T-shaped configuration. The crystal packing was found to be stabilized by weak intermolecular C-H&3x22EF;O interactions.

The title compound (systematic name: 6α-acet­oxy-4,5α-ep­oxy-3-meth­oxy-17-meth­yl-morphin-7-ene), C20H23NO4, crystallizes with one mol­ecule in the asymmetric unit. The mol­ecular structure exhibits features typical of morphine derivatives with a T configuration. The three-dimensional packing is stabilized by inter­molecular C—H⋯N and C—H⋯π inter­actions. [ABSTRACT FROM AUTHOR]

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]

The mol­ecule of the title compound, C21H22N2O2, is nearly planar, except for the C(CH3)2 group on the cyclo­hexene ring. Molecules are connected via electrostatic C⋯O contacts, forming zigzag pseudo-chains along the c axis. [ABSTRACT FROM AUTHOR]

In the title compound, NH4+·C4HO4−·H2O, the hydrogen squarate anions and water molecules are arranged to form planes almost parallel to bc. The ammonium cations are located between these planes and cross-link them in the a direction by means of an extensive network of hydrogen bonds. There are two symmetry-independent sets of cations and anions. One of the hydrogen squarate anions and one of the ammonium cations are situated on a twofold axis and the H atoms of these moieties are disordered over the symmetry-related sites. [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]

The asymmetric unit of the title compound, C9H12N+·C4H4O−, contains two independent 1,2,3,4-tetrahydroisoquinolinium cations and two independent hydrogensquarate anions. In one of the cations, the N atom is disordered over two positions with occupancies of approximately 0.8 and 0.2. The pyridinium rings adopt envelope conformations. The hydrogensquarate anions are linked to form cyclic tetramers through strong O—H...O hydrogen bonds. The tetrahydroisoquinolinium and hydrogensquarate ions are linked via N—H...O hydrogen bonds, forming a three-dimensional framework. [ABSTRACT FROM AUTHOR]

In the title compound, 3,4-dioxo-2-(pyridinium-1-yl)cyclobut-1-enolate, C9H5NO3, molecules are connected three-dimensionally through nonclassical C—H...O and π–π interactions [3.220 (3) Å] between the oppositely charged squarate and pyridinium fragments. Classical hydrogen-bonding interactions are not observed. In the unit cell, only half an independent molecule is present and a twofold rotation axis passes through the pyridinium ring and the opposite CO group. [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]

Cations and anions of the title compound {systematic name: 1-[4-(amino­carbonyl)butyl]guanidinium bis­(hydrogen­squarate)}, C6H17N5O2+·2C4HO4−, are connected into a three-dimensional network by inter­molecular N—H⋯O hydrogen bonds between thel-argininamidium ammonium, amide and guanidinium functions and the hydrogensquarate carbonyl O atoms. The independent hydrogensquarate monoanions are linked into dimers by pairs of O—H⋯O′ hydrogen bonds. [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]

Cations of the title compound, C5H11N2O+·C4HO4−, are connected by inter­molecular N(amide)— H⋯O(amide) hydrogen bonds into helical chains, whereas anions are inter­linked by strong O(hydrox­yl)—H⋯O hydrogen bonds into chains. These two distinct chains are interconnected by both N(amide)—H⋯O and N(ammonium)—H⋯O hydrogen bonds into a three-dimensional framework. One of the ammonium protons is involved in a three-centre hydrogen bond. [ABSTRACT FROM AUTHOR]

Cations of the title compound, C3H9N2O+·C4HO4−·H2O, are connected by inter­molecular Nammonium—H⋯Oamide hydrogen bonds into helical chains propagating in the [010] direction. These chains are further linked by Nammonium—H⋯O hydrogen bonds to the hydrogensquarate anions, which in turn form O—H⋯O-bridged chains in the [100] direction, thereby giving rise to a three-dimensional network. The water O atoms participate in two O—H⋯O hydrogen bonds to the anions and one O⋯H—Namide bridge to the cation. [ABSTRACT FROM AUTHOR]

Cations of the title compound, 1-carbamoyl-2-(4-hydroxy­phen­yl)ethyl­ammonium chloride monohydrate, C9H13N2O2+·Cl−·H2O, are connected by inter­molecular N—H⋯O [N⋯O = 2.905 (3) Å] hydrogen bonds between the amide and 4-hydr­oxy functions into helical chains propagating along the [010] axis. The Cl− ions and water O atom participate in a complex pattern of hydrogen bonds to link these ribbons into a three-dimensional network. [ABSTRACT FROM AUTHOR]

Anions and cations of the title compound, C5H8N3+·C4HO4−, are connected by moderately strong intermolecular N—H...O hydrogen bonds into an infinite three-dimensional network. Hydrogen squarate anions form dimers through strong O—H...O interactions. [ABSTRACT FROM AUTHOR]

In the title compound, sodium 2-hydr­oxy-3,4-dioxocyclo­but-1-en-1-olate monohydrate, Na+·C4HO4−·H2O, the Na atom is six-coordinated by the O atoms from four hydrogensquarate anions and two water mol­ecules. The three-dimensional packing is stabilized by a system of hydrogen bonds. [ABSTRACT FROM AUTHOR]

The crystal structure of the title compound, C16H19N3, comprises neutral molecules of a dipolar Schiff base chromophore. A density functional theory (DFT) optimized structure at the B3LYP/6-31G(d) level is compared with the molecular structure in the solid state. The compound crystallizes in the noncentrosymmetric space group Pna2(1) with a herring-bone packing motif and is therefore a potential candidate for nonlinear optical effects in the bulk.

In the title compound, C(18)H(22)N(2)O(4), the dihedral angle between the pyrrolyl and quinolinyl fragments is 68.97 (2)°. Two non-classical intra-molecular C-H⋯O hydrogen bonds stabilize the mol-ecular geometry. In the crystal structure, mol-ecules form infinite chains via moderate inter-molecular N-H⋯O(CH(3)) hydrogen bonds.