Mechanism and Kinetics of Fluorescence Quenching of Fluorene-Endcapped Butatriene: A Microspectroscopic Study of the Discrete State Constructed in Microcrystals

The ground-state electronic structure and excited-state dynamics of a fluorene-endcapped butatriene were elucidated. Tetraphenyl-endcapped butatrienes had been known to exhibit unique photoluminescence properties in which fluorescence was completely quenched by ring closure to a fluorene scaffold. Femtosecond time-resolved microspectroscopy on the microcrystalline state and density functional theory calculations revealed that the quenching is derived from the fast nonradiative decay to the ground state and the internal conversion to the dark state.