posted on 2023-12-15, 15:00authored byMariusz Tasior, Olena Vakuliuk, Antoni Wrzosek, Valentine I. Vullev, Adam Szewczyk, Denis Jacquemin, Daniel T. Gryko
Quadrupolar A-D-A-type
1,4-dihydropyrrolo[3,2-b]pyrroles (DHPPs) bearing
pyridinium and quinolinium substituents
emit in the 500–600 nm region. The enhancement of electronic
communication between the electron-rich heterocyclic core and electron-deficient
peripheral substituents turned out to be crucial for achieving emission
enhancement in viscous media. DHPP bearing two 4-pyridinium substituents
has optical brightness 34,000 in glycerol and only 700 in MeOH, as
evidenced by measurements of the emission intensity and fluorescence
lifetimes in a series of polar solvents. Such behavior makes it an
excellent candidate for viscosity probes in fluorescence microscopy,
as demonstrated by the fluorescence imaging of H9C2 cardiomyocytes.