Influence Of hydrogen bonding on the Photo-physical properties of Diethylamino hydroxybenzoyl hexyl benzoate

Abstract

In this paper, the effects of different hydrogen bond types on the photophysical properties of DHHB were investigated by systematically investigating the changes of spectral properties of Diethylamino hydroxybenzoyl hexyl benzoate in protonic and aprotic solvents, and the formation and stability of hydrogen bonds were further studied. Studies have shown that different solvent types and solute concentrations would affected the type of hydrogen bonds, and temperature changes would affected the stability of hydrogen bonds. In aprotic solvents, DHHB could only formed intramolecular hydrogen bonds and DHHB-DHHB intermolecular hydrogen bonds. At low concentration (≤ 5µg/mL), the system mainly existed in the form of intramolecular hydrogen bonds. At this time, the fluorescence intensity and UV molar extinction coefficient changed little, indicating that intramolecular hydrogen bonds have little effected on the spectral properties of DHHB. With the increase of concentration, the number of intermolecular hydrogen bonds increased, UV molar extinction coefficient increased significantly, indicating that intermolecular hydrogen bonds were conducive to improving the UV absorption properties of DHHB. With the increase of temperature, the molar extinction coefficient of the system decreased, indicating that the increase of temperature would led to the decrease of the stability of hydrogen bond fracture between DHHB molecules and reduced the UV absorption performance of DHHB. In the protic solvent, the system also has DHHB-solvent intermolecular hydrogen bonds. With the increase of the proportion of protonic solvent in the system, the fluorescence intensity of the system decreased significantly and the UV integral area increased significantly, indicating that the hydrogen bond between DHHB-solvent molecules was beneficial to improve the UV absorption performance of DHHB.