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.