Syntheses, crystal structure, luminescent behaviors and Hirshfeld surface of salts with imidazole and benzimidazole-yl scaffolds

Abstract

To explore the new photoluminescent materials, two new salts with imidazole and benzimidazole moieties, namely, [HIBI]+Z− (Z= MBS– (1) and BS– (2) [IBI = 2-((1H-imidazol-1-yl)methyl)-1H-benzimidazole, MBS = p-methyl phenyl sulfonic acid, BS= benzene-sulfonic acid], were obtained through reacting IBI and phenyl sulfonic acids by slow evaporation method, respectively. Compounds 1 and 2 have been characterized by single-crystal X-ray diffraction, IR, powder X-ray diffraction (PXRD) and thermogravimetric analyses (TGA). In both compounds, a set of hydrogen bonds (C/N–H⋯O) can be evidently observed, through which a three-dimensional framework will be fabricated. The luminescent spectra show that the emission maximal peaks in compounds 1 and 2 can be observed to be 460 and 477 nm, respectively. By comparison with the free IBI, the emission maxima of compounds 1 and 2 are obviously red-shifted about 151 and 168 nm, respectively. The Hirshfield surface analysis further confirms that the C∙∙∙C close contacts can account for the photoluminescent spectra.