A DFT/TDDFT study of solvent polarity relevant ESIPT behavior for 3H-DC fluorophore

The molecular properties of the semi-aliphatic polyimide derivative with incorporating bulky hydrogen side groups (3H-DC) in solvents are studied theoretically. The optimal reaction path can be found to regulate an excited state intramolecular proton transfer (ESIPT) reaction. The strength of the hydrogen bond increases significantly, and contributes to the ESIPT reaction providing the driving force. From the rearrangement of charge, electron density distribution is also an extremely important positive factor in the ESIPT process. The potential barrier sizes in different solvents are compared, basing on which we present the increase of solvent polarity which promotes the occurrence of the ESIPT reaction for 3H-DC fluorophore.