Morpholinium 2-chloro-4-nitrobenzoate, 2-chloro-5-nitrobenzoate and 4-chloro-3-nitrobenzoate

A Comparative Study on Electro-Optic Effects of Organic N-Benzyl-2-Methyl-4-Nitroaniline and Morpholinium 2-Chloro-4-Nitrobenzoate Doped in Nematic Liquid Crystals E7

Improvements in electro-optical responses of LC devices by doping organic N-benzyl-2-methyl-4-nitroaniline (BNA) and Morpholinium 2-chloro-4-nitrobenzoate (M2C4N) in nematic liquid crystals (LCs) have been reported in this study. BNA and M2C4N-doped LC cells have the fall time that is fivefold and threefold faster than the pristine LC cell, respectively. The superior performance in fall time of BNA-doped LC cell is attributed to the significant decrements in the rotational viscosity and threshold voltage by 44% and 25%, respectively, and a strong additional restoring force resulted from the spontaneous polarization electric field of BNA. On the other hand, the dielectric anisotropy (Δε) of LC mixture is increased by 16% and 6%, respectively, with M2C4N and BNA dopants. M2C4N dopant induces a large dielectric anisotropy, because the phenyl-amine/hydroxyl in M2C4N induces a strong intermolecular interaction with LCs. Furthermore, BNA dopant causes a strong absorbance near the wavelength of 400 nm that filters the blue light. The results indicate that M2C4N doping can be used to develop a high Δε of LC mixture, and BNA doping is appropriate to fabricate a fast response and blue-light filtering LC device. Density Functional Theory calculation also confirms that BNA and M2C4N increase the dipole moment, polarization anisotropy, and hence Δε of LC mixture.

Synthesis, structure and toxicity evaluation of ethanolamine nitro/chloronitrobenzoates: a combined experimental and theoretical study

BACKGROUND

Nitroaromatic and chloronitroaromatic compounds have been a subject of great interest in industry and recently in medical-pharmaceutic field. 2-Chloro-4-nitro/2-chloro-5-nitrobenzoic acids and 4-nitrobenzoic acid are promising new agents for the treatment of main infectious killing diseases in the world: immunodeficiency diseases and tuberculosis.

RESULTS

New ethanolamine nitro/chloronitrobenzoates were synthesized and characterized by X-ray crystallography, UV-vis, FT-IR and elementary analysis techniques. The toxicity of the compounds prepared and correspondent components was evaluated using Hydractinia echinata as test system. A significant lower toxicity was observed for nitro-derivative compared with chloronitro-derivatives and individual components. Crystallographic studies, together with the chemical reactivity and stability profiles resulted from density functional theory and ab initio molecular orbital calculations, explain the particular behavior of ethanolamine 4-nitrobenzoate in biological test.

CONCLUSIONS

The experimental and theoretical data reveal the potential of these compounds to contribute to the design of new active pharmaceutical ingredients with lower toxicity.

Solid-State Versatility of the Molecular Salts/Cocrystals of 2-Chloro-4-nitrobenzoic Acid: A Case Study on Halogen Bonds

2-Chloro-4-nitrobenzoic acid (2c4n) is an antiviral agent used for the treatment of HIV infection and to boost the immune response in immune deficiency diseases. In the present study, a series of eight molecular salts of 2c4n with pyridyl and benzoic acid derivatives have been synthesized by a crystal engineering approach and were characterized structurally by various spectroscopic, thermal, and X-ray diffraction techniques. Crystal structures of all synthesized molecular salts were determined by single-crystal X-ray diffraction techniques. In all synthesized molecular salts, the charge-assisted acid···pyridine/amine heterosynthon was found to be the primary supramolecular synthon. The synthesized salts, namely, 2c4n.g and 2c4n.h salts were found to be isostructural. Further, in the current work, the occurrence of weak halogen bonds in the presence of strong hydrogen bonds in the synthesized and in the reported molecular salts/cocrystals of 2c4n has been investigated. A detailed inspection of the crystal structures of salts/cocrystals of 2c4n was carried out to demonstrate the importance of halogen bonds in these crystal structures. It was found that 4 out of 8 synthesized molecular salts and 12 out of 24 reported molecular adducts of 2c4n were found to exhibit halogen bonds in their crystal structures. A similar kind of conformational change was observed for molecular salts exhibiting halogen bonds in their crystal structures; however, the conformations were found to be slightly different in other molecular salts. It was observed that two-point primary supramolecular synthon and stronger intramolecular Cl···O halogen bonds in the molecular adducts of 2c4n are found to be more susceptible to exhibit halogen bonds in their crystal structures. Halogen bond interactions played a vital role in the crystal stabilization of these molecular adducts.

Cyclic heterotetrameric and low-dimensional hydrogen-bonded polymeric structures in the morpholinium salts of ring-substituted benzoic acid analogues

The morpholinium (tetrahydro-2H-1,4-oxazin-4-ium) cation has been used as a counter-ion in both inorganic and organic salt formation and particularly in metal complex stabilization. To examine the influence of interactive substituent groups in the aromatic rings of benzoic acids upon secondary structure generation, the anhydrous salts of morpholine with salicylic acid, C4H10NO(+)·C7H5O3(-), (I), 3,5-dinitrosalicylic acid, C4H10NO(+)·C7H3N2O7(-), (II), 3,5-dinitrobenzoic acid, C4H10NO(+)·C7H3N2O6(-), (III), and 4-nitroanthranilic acid, C4H10NO(+)·C7H5N2O4(-), (IV), have been prepared and their hydrogen-bonded crystal structures are described. In the crystal structures of (I), (III) and (IV), the cations and anions are linked by moderately strong N-H...Ocarboxyl hydrogen bonds, but the secondary structure propagation differs among the three, viz. one-dimensional chains extending along [010] in (I), a discrete cyclic heterotetramer in (III), and in (IV), a heterotetramer with amine N-H...O hydrogen-bond extensions along b, giving a two-layered ribbon structure. With the heterotetramers in both (III) and (IV), the ion pairs are linked though inversion-related N-H...Ocarboxylate hydrogen bonds, giving cyclic R4(4)(12) motifs. With (II), in which the anion is a phenolate rather than a carboxylate, the stronger assocation is through a symmetric lateral three-centre cyclic R1(2)(6) N-H...(O,O') hydrogen-bonding linkage involving the phenolate and nitro O-atom acceptors of the anion, with extension through a weaker O-H...Ocarboxyl hydrogen bond. This results in a one-dimensional chain structure extending along [100]. In the structures of two of the salts [i.e. (II) and (IV)], there are also π-π ring interactions, with ring-centroid separations of 3.5516 (9) and 3.7700 (9) Å in (II), and 3.7340 (9) Å in (IV).

Crystal structure of morpholin-4-ium cinnamate

In the anhydrous salt formed from the reaction of morpholine with cinnamic acid, C4H10NO(+)·C9H7O2 (-), the acid side chain in the trans-cinnamate anion is significantly rotated out of the benzene plane [C-C-C- C torsion angle = 158.54 (17)°]. In the crystal, one of the the aminium H atoms is involved in an asymmetric three-centre cation-anion N-H⋯(O,O') R 1 (2)(4) hydrogen-bonding inter-action with the two carboxyl-ate O-atom acceptors of the anion. The second aminium-H atom forms an inter-species N-H⋯Ocarboxyl-ate hydrogen bond. The result of the hydrogen bonding is the formation of a chain structure extending along [100]. Chains are linked by C-H⋯O inter-actions, forming a supra-molecular layer parallel to (01-1).

Crystal structures and hydrogen bonding in the morpholinium salts of four phen-oxy-acetic acid analogues

The anhydrous salts morpholinium (tetra-hydro-2-H-1,4-oxazin-4-ium) phen-oxy-acetate, C4H10NO(+)·C8H7O3 (-), (I), morpholinium (4-fluoro-phen-oxy)acetate, C4H10NO(+)·C8H6 FO3 (-), (II), and isomeric morpholinium (3,5-di-chloro-phen-oxy)acetate (3,5-D), (III), and morpholinium (2,4-di-chloro-phen-oxy)acetic acid (2,4-D), C4H10NO(+)·C8H5Cl2O3 (-), (IV), have been determined and their hydrogen-bonded structures are described. In the crystals of (I), (III) and (IV), one of the the aminium H atoms is involved in a three-centre asymmetric cation-anion N-H⋯O,O' R 1 (2)(4) hydrogen-bonding inter-action with the two carboxyl O-atom acceptors of the anion. With the structure of (II), the primary N-H⋯O inter-action is linear. In the structures of (I), (II) and (III), the second N-H⋯Ocarbox-yl hydrogen bond generates one-dimensional chain structures extending in all cases along [100]. With (IV), the ion pairs are linked though inversion-related N-H⋯O hydrogen bonds [graph set R 4 (2)(8)], giving a cyclic hetero-tetra-meric structure.