Jump to main content
Jump to site search
PLANNED MAINTENANCE Close the message box

Scheduled maintenance work on Wednesday 27th March 2019 from 11:00 AM to 1:00 PM (GMT).

During this time our website performance may be temporarily affected. We apologise for any inconvenience this might cause and thank you for your patience.


Issue 38, 2018
Previous Article Next Article

Excited state intramolecular proton transfer in julolidine derivatives: an ab initio study

Author affiliations

Abstract

We have studied, using ab initio tools, a series of recently prepared fluorescent julolidine derivatives, undergoing Excited State Intramolecular Proton Transfer (ESIPT). We show that the computed free energy change in the excited state (ΔGES) can be used to predict the preference for enol, keto, or dual emission. Indeed, two julolidine molecules experimentally show dual emission, consistent with our finding of a small ΔGES. In agreement with experimental outcomes the complexation between the ESIPT centre and BF2 increases the rigidity of the fluorophore and greatly facilitates emission at energies close to the original enol (E*) fluorescence band. The protonation of the imino group also suppresses ESIPT and sole E* emission is obtained. We disclose that chemical substitution can significantly tune the radiationless deactivation of the enol related to the C[double bond, length as m-dash]N bond rotation of the ESIPT centre. While there is a significant barrier for the experimentally studied compounds we have found a strong correlation between the barrier height and the electron donating strength of the phenyl substituent. Strong donors such as amines facilitate the barrierless non-radiative decay from E* back to the ground state, while weak electron donors make the barrier sufficiently high to allow ESIPT. Strong electron accepting groups such as –NO2 further increase this barrier. This work therefore illustrates the fine interplay necessary to design dual emitters.

Graphical abstract: Excited state intramolecular proton transfer in julolidine derivatives: an ab initio study

Back to tab navigation

Supplementary files

Publication details

The article was received on 10 Jul 2018, accepted on 13 Sep 2018 and first published on 13 Sep 2018


Article type: Paper
DOI: 10.1039/C8CP04356F
Citation: Phys. Chem. Chem. Phys., 2018,20, 25031-25038

  •   Request permissions

    Excited state intramolecular proton transfer in julolidine derivatives: an ab initio study

    Š. Budzák and D. Jacquemin, Phys. Chem. Chem. Phys., 2018, 20, 25031
    DOI: 10.1039/C8CP04356F

Search articles by author

Spotlight

Advertisements