Supersonic jet and solution studies of intramolecular complexes with TICT formation mimicking solute–solvent interaction Original Research Article

Three ester derivatives of N,N-dimethylaniline have been studied, which possess a flexibly linked intramolecular hydroxyl group amenable to mimic 1:1 complexation of donor–acceptor molecules with solvent molecules. The supersonic jet fluorescence excitation spectra indicate a small redshift for these intramolecularly complexed compounds with respect to the noncomplexed model compounds giving evidence for the intramolecular complexation by hydrogen bond formation at the ester group. The dispersed fluorescence spectra broaden upon an increase in the excitation energy. Semiempirical simulated annealing calculations using AMPAC/AM1 show that there exist many possible conformations of similar energy for the molecule, with H bonding at the carbonyl or alkoxy oxygen in the most stable conformer. A shift in the carbonyl vibrational frequencies is consistent with a carbonyl self-complexed species.