1 research outputs found
Emergence of Chiroptical Properties in Molecular Assemblies of Phenyleneethynylenes: The Role of Quasi-degenerate Excitations
Chiroptical
properties of supramolecular assemblies originate through
the asymmetric coupling of molecular transition dipole moments. Herein,
we report a joint experimental and theoretical investigation to understand
the influence of intermolecular interactions on chiroptical properties,
particularly during the early stages of self-assembly. In this regard,
phenyleneethynylene-based molecular systems appended with d- and l-isomers of phenylalanine have been synthesized with
one as well as two electronic transitions in the spectral region of
interest. When self-assembled, these molecules show distinctly different
chiroptical properties with the right- and left-handed organizations,
guided by the chirality of phenylalanines. The standard exciton approach
explains the observation of a bisignated electronic circular dichroism
signal in systems with a single transition but fails when applied
to systems with two nearby transitions. Here, we present a generalized
exciton approach that addresses the unusual chiroptical properties
of systems with multiple transitions