RESUMEN

The structural and nonlinear optical properties of a new anilinium hybrid crystal of chemical formula (C6H7NCl+·NO3-)3 have been investigated. The crystal structure was determined from single-crystal X-ray diffraction measurements performed at a temperature of 100 K which show that the compound crystallizes in a noncentrosymmetric space group (Pna21). The structural analysis was coupled with Hirshfeld surface analysis to evaluate the contribution of the different intermolecular interactions to the formation of supramolecular assemblies in the solid state that exhibit nonlinear optical features. This analysis reveals that the studied compound is characterized by a three-dimensional network of hydrogen bonds and the main contributions are provided by the O...H, C...H, H...H and Cl...H interactions, which alone represent ∼85% of the total contributions to the Hirshfeld surfaces. It is noteworthy that the halogen...H contributions are quite comparable with those of the H...H contacts. The nonlinear optical properties were investigated by nonlinear diffuse femtosecond-pulse reflectometry and the obtained results were compared with those of the reference material LiNbO3. The hybrid crystals exhibit notable second (SHG) and third (THG) harmonic generation which confirms its polarity is generated by the different intermolecular interactions. These measurements also highlight that the THG signal of the new anilinium compound normalized to its SHG counterpart is more pronounced than for LiNbO3.

RESUMEN

Two polymorphs of L-aspartic acid hydrochloride, C4H8NO4(+)·Cl(-), were obtained from the same aqueous solution. Their crystal structures have been determined from single-crystal data collected at 100 K. The crystal structures revealed three- and two-dimensional hydrogen-bonding networks for the triclinic and orthorhombic polymorphs, respectively. The cations and anions are connected to one another via N-H···Cl and O-H···Cl interactions and form alternating cation-anion layer-like structures. The two polymorphs share common structural features; however, the conformations of the L-aspartate cations and the crystal packings are different. Furthermore, the molecular packing of the orthorhombic polymorph contains more interesting interactions which seems to be a favourable factor for more efficient charge transfer within the crystal.

Asunto(s)

RESUMEN

In the crystal structure of the title salt, C4H6N3O(+)·HSeO3 (-), systematic name 6-amino-2-methyl-idene-2,3-di-hydro-pyrim-idin-1-ium hydrogen selenite, the hydrogenselenite anions and the cytosinium cations are linked via N-H⋯O, N-H⋯Se, O-H⋯O, O-H··Se and C-H⋯O hydrogen bonds, forming a three-dimensional framework.

RESUMEN

The crystal structure of a polymorph of 4-aminobenzoic acid (PABA), C7H7NO2, at 100 K is noncentrosymmetric, as opposed to centrosymmetric in the structures of the other known polymorphs. The two crystallographically independent PABA molecules form pseudocentrosymmetric O-H...O hydrogen-bonded dimers that are further linked by N-H...O hydrogen bonds into a three-dimensional network. The benzene rings stack in the b direction. The CO2 moieties are bent out slightly from the benzene ring plane.

Asunto(s)

RESUMEN

There are two crystallographically independent cations and two anions in the asymmetric unit of the title compound, C(4)H(5)NO(2) (+)·NO(3) (-). In the crystal, the 1-carb-oxy-propanaminium cations and nitrate anions are linked to each other through strong N-H⋯O and O-H⋯O hydrogen bonds, forming a three-dimensional complex network. C-H⋯O inter-actions also occur.

RESUMEN

In the title complex, [Ni(C(5)H(9)NO(2))(2)(H(2)O)(2)], the Ni(II) atom, located on a centre of inversion, is trans-coordinated by two O atoms and two N atoms from d-bidentate valine and l-bidentate valine ligands and two water O atoms in an octa-hedral geometry. In the crystal, the discrete mononuclear units are linked into a three-dimensional network via O-H⋯O and N-H⋯O hydrogen bonds. C-H⋯O inter-actions are also observed.