Aggregation Induced Emission
of Cycloheptatrienylidene Fluorophores
Goal: The goal of this project is
to use hypervalent iodonium alkynyl triflates to
synthesize molecules that fluoresce upon
aggregation. This is the group's flagship project
and incorporates target synthesis, methodology
development, computational chemistry, fluorescence,
solid-state chemistry, and metal coordination
chemistry.
Summary: Typically, luminescence
of a fluorophore is decreased as the solution is
concentrated thereby rendering many solid state
applications impractical. Increasing luminescence
upon concentration of a solution can occur in
certain cases where there is a restriction of
intramolecular rotation in the aggregate. The core
structure of the molecules used to accomplish
aggregation induced emission will consist of an
asymmetrically substituted cycloheptatrienylidene. A
new method of synthesizing cycloheptatrienylidenes
from hypervalent iodonium alkynyl triflates will be
developed for the purpose of exploring how different
structural changes can have effects on aggregation.
To induce fluorescence, metal salts will be added to
the cycloheptatrienylidenes to aromatize the
7-membered ring, cause an aggregation, and produce
an emission. The project will also use ab-intio
calculations to probe the electronic structure of
the synthesized molecules. To translate these
complexes into applicable materials, the nature of
the excitation will be investigated. Current
theories suggest that the emission can come from a
charge transfer and/or a d-d transition but this has
not been investigated in the literature. A long-term
goal for the project is to create non-toxic
fluorophores that aggregate and “turn-on”
fluorescence by using endogenous metals in the body.
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