Presentation day

Tuesday  3:40 PM

 

TITLE

Rational Design of Naphthalimide-Capped Peptides with Aggregation-Induced Emission Characteristics

 

Abstract

Since the discovery of supramolecular chemistry, it has been proved that the use of pconjugated
system as hydrophobic unit is an efficient way to construct a new self-assembly system.1
Accordingly, the p-conjugated fluorophores can be incorporated into the design of new fluorescent
moleucules for bioimaging applications. However, aggregation of p-conjugated fluorophores usually
quenches their light emission, which is denoted as aggregation-caused quenching (ACQ). In contrast, a
class of molecules with weakly fluorescent properties in isolated state but highly emissive in aggregate
state that is known as aggregation-induced emission (AIE). Owing to the unique advantages, a large
number of AIE systems with various emission colors covering the entire visible range were developed by
many research groups. Herein, we have synthesized a series of naphthalimide(NI)-capped peptides and
found that the substitution effects of NI chromophores may dictate the AIE or ACQ properties of the selfassembled
systems in water. We have employed the nitrogenated heterocyclics, which are on the forth site
of 1,8-naphthalimide (NI), as the electron donating groups to vary the florescent properties. Interestingly,
the emission intensity of water fraction = 99 vol% of substituted naphthalimide-capped peptides (6RNI-FF)
dramatically increased upon increasing water content, which was consistent with a typical AIE feature
(Scheme 1).2 These findings illustrate the importance of the structure-property relationship in the design of
new water-soluble self-assembled systems with AIE characteristics.