Dihydrogen phosphate mediated supramolecular frameworks in 2- and 4-chloroanilinium dihydrogen phosphate salts

Nonlinear optical organic-inorganic crystals: synthesis, structural analysis and verification of harmonic generation in tri-(o-chloroanilinium nitrate)

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.

Crystal structure of bis-(2-amino-anilinium) hydrogen phosphate

The asymmetric unit of the title compound, 2C6H9N2 (+)·HPO4 (2-), comprises two 2-amino-anilinium cations and one hydrogen phosphate dianion. In the crystal, the HPO4 (2-) dianions are linked by O-H⋯O hydrogen bonds into chains along [100]. The inorganic anionic chains and organic cations are linked by N-H⋯O and N-H⋯N hydrogen bonds, forming a two-dimensional supra-molecular network extending parallel to (001).

A dihydrogen phosphate anionic network as a host lattice for cations in 1-methylpiperazine-1,4-diium bis(dihydrogen phosphate) and 2-(pyridin-2-yl)pyridinium dihydrogen phosphate-orthophosphoric acid (1/1)

In the salt 1-methylpiperazine-1,4-diium bis(dihydrogen phosphate), C5H13N2(2+)·2H2PO4(-), (I), and the solvated salt 2-(pyridin-2-yl)pyridinium dihydrogen phosphate-orthophosphoric acid (1/1), C10H9N2(+)·H2PO4(-)·H3PO4, (II), the formation of O-H...O and N-H...O hydrogen bonds between the dihydrogen phosphate (H2PO4(-)) anions and the cations constructs a three- and two-dimensional anionic-cationic network, respectively. In (I), the self-assembly of H2PO4(-) anions forms a two-dimensional pseudo-honeycomb-like supramolecular architecture along the (010) plane. 1-Methylpiperazine-1,4-diium cations are trapped between the (010) anionic layers through three N-H...O hydrogen bonds. In solvated salt (II), the self-assembly of H2PO4(-) anions forms a two-dimensional supramolecular architecture with open channels projecting along the [001] direction. The 2-(pyridin-2-yl)pyridinium cations are trapped between the open channels by N-H...O and C-H...O hydrogen bonds. From a study of previously reported structures, dihydrogen phosphate anions show a supramolecular flexibility depending on the nature of the cations. The dihydrogen phosphate anion may be suitable for the design of the host lattice for host-guest supramolecular systems.

2-Chloro-anilinium perchlorate

In the crystal of the title compound, C(6)H(7)ClN(+)·ClO(4) (-), a layer-like structure parallel to the bc plane is formed through N-H⋯O hydrogen bonds between the cations and anions. These layers are connected by weak C-H⋯O inter-actions, forming a three-dimensional network.

4-Chloro-anilinium 3-carb-oxy-prop-2-enoate

In the title compound, C(6)H(7)ClN(+)·C(4)H(3)O(4) (-), the cations and anions lie on mirror planes and hence only half of the mol-ecules are present in the asymmeric unit. The 4-chloro-anilinium cation and hydrogen maleate anion in the asymmetric unit are each planar and are oriented at an angle of 15.6 (1)° to one another and perpendicular to the b axis. A characterestic intra-molecular O-H⋯O hydrogen bond, forming an S(7) motif, is observed in the maleate anion. In the crystal, the cations and anions are linked by N-H⋯O hydrogen bonds, forming layers in the ab plane. The aromatic rings of the cations are sandwiched between hydrogen-bonded chains and rings formed through the amine group of the cation and maleate anions, leading to alternate hydro-phobic (z = 0 or 1) and hydro-philic layers (z = 1/2) along the c axis.

Anilinium dihydrogen phosphate

The triclinic structure of the title compound, C(6)H(8)N(+)·H(2)PO(4)(-), with three symmetry-independent structural units (Z' = 3), is formed of separate organic and inorganic layers alternating along the b axis. The building blocks of the inorganic layer are deformed H(2)PO(4) tetrahedra assembled into infinite ladders by short and hence strong hydrogen bonds. The anilinium cations forming the organic layer are not hydrogen bonded to one another, but they are anchored by four N-H···O crosslinks between the dihydrogen phosphate chains of adjacent ladders. Two H atoms of each -NH(3) group then form one normal and one bifurcated N-H···O hydrogen bond to the P=O oxygens of two tetrahedra of one chain, while the third H atom is hydrogen bonded to the nearest O atom of an adjacent chain belonging to another dihydrogen phosphate ladder.