Influence of Hydrogen Bonds and Nonspecific Interactions on the Spectral and Photophysical Properties of the Excited Singlet States of 4‐Aminophthalimide in Amine Solution

Abstract

The hydrogen-bond and nonspecific interaction energies for 4-aminophthalimide (4-AP), often used as a probe, in the ground electronic and excited singlet states are determined using ab initio computational methods. It is shown that the 4-AP molecule can form three relatively strong hydrogen bonds with trimethylamine (TMA) and triethylamine (TEA), which leads to the formation of S(0)-complexes between the solute and solvent molecules. Only two of the hydrogen bonds with the amine group of 4-AP change significantly their energies upon excitation and deactivation. The theoretical results are necessary to explain the spectral and unusual photophysical properties of 4-AP in amine solutions.