posted on 2021-10-05, 14:45authored byGoutam Chakraborty, Jotiram N. Malegaonkar, Sidhanath V. Bhosale, Prabhat K. Singh, Haridas Pal
Aggregation-induced emission (AIE)
of fluorogenic dyes offers many
opportunities as smart materials, fluorescence sensing of analytes,
bioimaging, molecular electronics, and many others. AIE dyes (called
AIEgens) produce emission through aggregation, which are more advantageous
than conventional emission of monomeric fluorophores, as the latter
is unduly susceptible toward various quenching processes. Here, we
report AIE enhancement of a polyanionic sulfonato-tetraphenylethylene
(SuTPE) derivative, achieved through supramolecularly assisted dye
aggregation, as SuTPE interacts with a multicationic amino-β-cyclodextrin
(AβCD) host. Aggregation of the dye is induced mainly because
of strong electrostatic interaction of SuTPE with AβCD, causing
a significant extent of charge neutralization for the polyanionic
dyes, helping their assemblage at the multicationic host portal. Job’s
plot studies suggest preferential formation of 2:1 dye-to-host stoichiometric
complexes in the present system. Ionic-strength-dependent studies
nicely support the involvement of electrostatic interaction in the
present system through salt-induced disintegration of the SuTPE–AβCD
complexes. The AIE enhancement for the SuTPE–AβCD system
is very sensitive to the external stimuli, such as pH and temperature,
suggesting its prospects in various stimuli-responsive applications.
Furthermore, the SuTPE–AβCD system can suitably quantify
an important bioanalyte, ATP, following a competitive binding strategy,
suggesting its potential application as a supramolecular biosensor.