Spectroscopic and theoretical studies of bis(dimethylphenyl betaine) hydrochloride monohydrate

•FTIR and Raman spectra of bis(dimethylphenyl betaine) hydrochloride monohydrate were studied.•Combined vibrational spectroscopic and B3LYP studies of bis(dimethylphenyl betaine) hydrochloride monohydrate are presented.•Hydrogen bonds are analyzed.

Bis(dimethylphenyl betaine) hydrochloride monohydrate was prepared and characterized by FTIR, Raman spectroscopes, and B3LYP/6-311++G(d,p) calculations. In the optimized structure of the complex, two betaine moieties are joined by a very strong asymmetric hydrogen bond with an O⋯O distance of 2.439 Å. The water molecule is H-bonded to one oxygen atom of dimethylphenyl betaine and chloride anion via O(w)⋯O(2) and O(w)⋯Cl distances of 3.099 and 3.167 Å, respectively. The potential energy distributions (PED) were used for the assignments of IR and Raman frequencies in the experimental and calculated spectra of the title compound. Chloride anion interacts electrostatically with N+ atoms.