Crystalline network study of new N-phthaloyl-β-Alanine with benzimidazole, cocrystal: Computational consideration & free radical scavenging activity

Abstract

The new cocrystal adducts of N-phthaloyl-β-alanine and benzimidazole (1:2) with molecular formula C18H15N3O4 (1) was synthesized by slow evaporation process of the aqueous solution containing the two said moieties. The confirmation of proposed formula can be established through crystal structure as well as FTIR analysis. The crystal structure was confirmed by single X–ray crystal analysis. The experimental and theoretical studies of photophysical properties like Fourier Transform Infrared (FTIR) and ultraviolet–visible spectroscopy (UV–Vis) have been done. The cocrystal belong to monoclinic crystallographic system with space group P21/c, Z = 4. DPPH radical scavenging activity of the title cocrystal is slightly lower than coformer with lower IC50 value, respectively. One dimensional infinite chain in direction of [010] parallel to b direction. Optimized crystalline network structure of 1 shows that conventional N−H⋯O, and OH⋯N, and the non−conventional CH⋯O hydrogen bonds (HBs) gathered the monomeric components of 1 (1−mon). The reliable calculations of the dispersion corrected density functional theory (DFT−D) display that N−H⋯O and O−H⋯N HBs more share in the stabilization of the network structure. The theoretical study of UV–Vis spectra in solvents (water, acetonitrile, methanol, and n–heptanes) confirms the experimental results as seven main bands in 180–270 nm range. They could attribute to intra-ligand charge transfer (ILCT) as benzimidazole → benzimidazole and N-phthaloyl-β-alanine → N-phthaloyl-β-alanine with π → π* character.