Spectroscopy of Benzodiazepine‐2,4‐Dione in Solution

Abstract

The absorption and emission spectra of benzodiazepine‐2,4‐dione in solution were measured at room temperature. Assignments of the electronic transitions involved are suggested on the basis of absorption, emission spectra, solvent effects, and fluorescence lifetimes. The shift of the absorption band with increasing solvent polarity is mainly due to dipolar and hydrogen bond interactions between solute and solvent molecules. Furthermore, quantum yields and fluorescence lifetimes have been evaluated in each solvent. Analysis of the results suggests that the hydrogen bond and the dipolar interactions play an equivalent role in stabilization of the first singlet excited state. An energy diagram explaining the different radiative and nonradiative processes has been suggested.

Keywords:

• Absorption
• benzodiazepine‐2,4‐dione
• fluorescence
• hydrogen bond
• solvent effects

Acknowledgment

This work was supported by the Morocco‐French cooperation CNRS/CNRST no. 15817.