Crystal growth and physical properties of the organic salt benzimidazolium 3-nitrophthalate

Abstract

From the point of view of crystal growth and design, it is interesting to study the effect of different isomers on the resulting structure. Single crystals of the organic salt benzimidazolium 3-nitrophthalate (BZD + •mNPA − ) have been grown by slow evaporation from methanol solution. Single crystal X-ray diffraction demonstrated that the crystal structure belongs to the monoclinic system with space group P2 1 /c. The properties of the functional groups have been studied by FTIR spectroscopy, FT-Raman spectral analysis and 1 H and 13 C NMR spectroscopy. The emission spectra of BZD + •mNPA − were recorded in different solvents; they exhibit a negative solvatochromatic effect when the polarity of the solvent is increased. The thermal stability, dielectric constant and dielectric loss have been investigated and the HOMO and LUMO energy levels have been calculated using density functional theory (DFT). The crystal structure of BZD + •mNPA − has been compared with that of benzimidazolium 2-nitroterephthalate (BZD + •NTPh − ). The interactions of the isomers 3-nitrophthalate or 2-nitroterephthalate salts with benzimidazolium are very similar; however, the different positions of the carboxyl groups on the benzene rings changes the layout of the structure, which leads to undulating sheets for 3-nitrophthalate and flat antiparallel sheets for 2-nitrotherephthalate. The salt decomposes at around 180 °C.

Growth, structure, Hirshfeld surface and spectroscopic properties of 2-amino-4-hydroxy-6-methylpyrimidinium-2,3-pyrazinedicorboxylate single crystal

“…In AHMP molecule, the d CH3 is identified at 1.99 ppm. In the simulated 1 H NMR spectrum, the signals due to H25 and H22 hydrogens are found at 15.78 ppm and 13.42 ppm which indicate the existence of strong NeH þ /O À and NeH/O hydrogen bonds, respectively in the PDCA À .AHMP þ[67,68]. However these signals were not observed in recorded 1 H NMR spectrum because it was measured in the 0e10 ppm region.…”

Uncovering the origins of supramolecular similarity in a series of benzimidazole structures

“…Pogorzelec-Glaser et al 30 studied the formation of benzimidazole salts with dicarboxylic acids (glutaric and pimelic acids), showing that NH⋯O hydrogen bonds link the two different molecules present in the crystal. The benzimidazole salt and 3-nitrophthalic acid were reported and characterized by Mekala et al , 31 who showed that the ions were connected via strong N–H⋯O interactions.…”

Molecular Structural, Hydrogen Bonding Interactions, and Chemical Reactivity Studies of Ezetimibe-L-Proline Cocrystal Using Spectroscopic and Quantum Chemical Approach

“…In an approach to develop pharmaceutical compound, improvisation of the physicochemical properties of drugs are needful. Recent research works on cocrystals have drawn much attention toward pharmaceutical applications where properties such as solubility, dissolution rate, bioavailability, hardness (or tableting), and stability of a drug can be improved leaving the chemical properties of pure API unchanged ( Chan et al, 2013 ; Dudenko et al, 2013 ; Pagire et al, 2013 ; Sarma and Saikia, 2014 ; Mekala et al, 2016 ; Saikia et al, 2016 ). Cocrystals are crystalline materials composed of multiple components, one being an API and other being a pharmaceutically acceptable coformer connected via hydrogen bond, halogen bonds, and π−π interactions ( Ali et al, 2012 ; Pandey et al, 2016 ).…”