XRD, NMR, FT-IR and DFT structural characterization of a novel organic-inorganic hybrid perovskite-type hexabromotellurate material

Abstract

The synthesis of a new hexabromotellurate of triazole ring-containing amino acid is described. XRD, NMR and DFT analysis of the structure of protonated [(5-amino-4-phenyl-4H-1,2,4-triazol-3-yl)sulfanyl]acetic acid testifies the protonation of the first nitrogen atom of the triazole ring. Hirshfeld surface analysis identifies numerous intermolecular interactions in the newly synthesized organic-inorganic hybrid hexabromotellurate. The DFT based comprehensive analysis of the structures of possible conformers also testifies the higher thermodynamic stability of the 1-protonated triazole cation, whereas the starting [(5-amino-4-phenyl-4H-1,2,4-triazol-3-yl)sulfanyl]acetic acid exists in solution in neutral form with the intermolecular hydrogen bond between the carboxylic acid OH group and the second nitrogen of the triazole ring. The experimentally observed NMR upfield shift of the signal of the exocyclic amino group was studied via GIAO computations and was explained through the analysis of the HOMOs of the neutral and protonated forms of the triazole compound.