A tetraphenylethene-decorated BODIPY monomer/dimer with intense fluorescence in various matrices

Three novel boron dipyrromethene (BODIPY) derivatives containing tetraphenylethene (TPE) with emissions ranging from orange to red were synthesized and characterized. Spectroscopic properties of the dyes in various solvents and in the solid state have been investigated. They all exhibit high fluorescence intensity in solution and moderate fluorescence in the solid state, due to inhibiting intermolecular pi-pi stacking resulting from tetraphenylethene substituents. Cyclic voltammetry and time-dependent density functional theory (TD-DFT) calculations were carried out to explore the electronic coupling between the tetraphenylethene group and the BODIPY unit, giving consistent results with photophysical measurements.