Quantum mechanics

Intramolecular force

Process (computing)

Chemical physics

Photochemistry

Materials science

Aromaticity

Operating system

Atomic physics

Molecule

Computer science

Stereochemistry

Physics

Organic chemistry

Molecular physics

Fluorescence

Computational chemistry

Aggregation-induced emission

Excited state

Chemistry

Annulene

Nature Communications

Aggregation-induced emission (AIE) is a photophysical phenomenon correlated closely with the excited-state intramolecular motions. Although AIE has attracted increasing attention due to the significant applications in biomedical and optoelectronics, an in-depth understanding of the excited-state intramolecular motion has yet to be fully developed. Here we found the non-aromatic annulene derivative of cyclooctatetrathiophene shows typical AIE phenomenon in spite of its rotor-free structure. The underlying mechanism is investigated through photoluminescence spectra, time-resolved absorption spectra, theoretical calculations, circular dichroism as well as by pressure-dependent fluorescent spectra etc., which indicate that the aromaticity reversal from ground state to the excited state serves as a driving force for inducing the excited-state intramolecular vibration, leading to the AIE phenomenon. Therefore, aromaticity reversal is demonstrated as a reliable strategy to develop vibrational AIE systems. This work also provides a new viewpoint to understand the excited-state intramolecular motion behavior of lumiongens.

Non-aromatic annulene-based aggregation-induced emission system via aromaticity reversal process