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Download fileSymmetry-Breaking Charge Separation in a Nanoscale Terrylenediimide Guanine-Quadruplex Assembly
journal contribution
posted on 2019-10-28, 19:36 authored by Natalia
E. Powers-Riggs, Xiaobing Zuo, Ryan M. Young, Michael R. WasielewskiGuanine-quadruplex (G-quadruplex)
assemblies provide a useful platform
for studying the spatial, structural, and photophysical effects of
intermolecular interactions. Coupling a single guanine moiety to terrylenediimide
(TDI)a chromophore with a large extended π-surfaceproduces
a structure (GTDI) that assembles in plate-like tetramers,
with the potential of undergoing tunable π-stacking. At high
concentrations (3 × 10–3 M), GTDI self-assembles into a nearly monodisperse G-quadruplex structure
of 16 layers, with strong π-overlap between TDI moieties, observed
by small- and wide-angle X-ray scattering. Transient absorption spectroscopy
reveals that excitation of TDI in the G-quadruplex results in symmetry-breaking
charge separation to form ion pairs within the structure, owing to
the strong π-overlap enforced by the hydrogen-bonding. These
assemblies yield important insights into the interplay of noncovalent
interactions in the assembly of ordered chromophoric arrays.