Experimental and Theoretical Study on the Interactions between Dopamine Hydrochloride and Vitamin B6 Hydrochloride.

The interactions between dopamine hydrochloride (DH) and vitamin B6 hydrochloride (VH) in aqueous solution were investigated by means of cyclic voltammetry (CV), ¹H NMR, density functional theory (DFT), quantum theory of atoms in molecules (QTAIM) and reduced density gradient (RDG). The results from CV and NMR experiments indicate the π–π stacking between the benzene ring of DH and the pyridine ring of VH, which is confirmed by theoretical calculations. Furthermore, six DH-VH complexes obtained by geometry optimization contain hydrogen bonds, π–π stacking and C–H–π interactions, and π–π stacking play a vital role in DH–VH–H₂O system. This work provides the insights on the interactions of DH with VH at molecular level and is favorable to their clinical and pharmaceutical applications. [ABSTRACT FROM AUTHOR]