Journal of the American Chemical Society · 2004 · 223 citations · 1 references
Natural SciencesChemistryPhysicsBiophysical ChemistryChemical KineticsSupramolecular ChemistryCoordination ChemistryFluorescence SpectroscopyLight HarvestingPhotochemical KineticsPhotochemistryTransition Metal ComplexesChromophore PhotochemistryChromophore PhotophysicsExcited-state DynamicsMolecular ChromophoresPhotochemical EffectsPhotochemical ReactionsPhotophysical MechanismsSteric Constraints
The replacement of the phenyl rings at the 5,5'-positions of a bis(dipyrrinato)zinc complex with mesityl groups transforms the molecule from a very weak emitter that deactivates rapidly after photoexcitation (Phif = 0.006; tau approximately 90 ps) to a highly fluorescent chromophore with a long-lived singlet excited state (Phif = 0.36; tau approximately 3 ns). The results demonstrate that steric constraints on aryl-ring internal rotation dramatically alter the excited-state properties of 5,5'-substituted bis(dipyrrinato)metal complexes. The insights establish the foundation for tuning the photophysical properties of these chromophores for use in diverse photochemical applications.
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