부산대학교 도서관

The conformational state and noncovalent interaction of protonated dopamine (p-dopamine) play an important role in its key and lock binding with its receptors. Hence, understanding of the role of weak noncovalent interactions in the stability of the higher order structures of the p-dopamine is desired. In this study, we have combined the spectroscopic and quantum chemical calculation studies to understand the role of noncovalent interactions in the stability of the dimers and trimers of p-dopamine in the aqueous medium. The intensity of the UV–Visible spectra of p-dopamine increases and shows a red shift with increasing concentrations suggesting the presence of the higher order structures of p-dopamine in the aqueous medium. The quantum chemical calculations and AIM studies of the different structures of its dimer and trimers suggest the presence of N–H3+…π, C–H…π, π…π weak interactions along with conventional N–H…O hydrogen bond. The calculated peak positions of the UV–Visible spectra of different clusters show that the higher order of clusters show red shifted peak position compared to the monomer and the red shifted peak is more evident in the clusters having noncovalent interactions. Weak noncovalent interactions stabilise higher order clusters of protonated dopamine leading to red shift in the UV-visible spectra as shown by quantum chemical calculations. [ABSTRACT FROM AUTHOR]