jp5b09665_si_001.pdf (1.41 MB)
Spectroscopic Evidence for Through-Space Arene–Sulfur–Arene Bonding Interaction in m‑Terphenyl Thioether Radical Cations
journal contribution
posted on 2015-12-31, 00:00 authored by Nicolas
P.-A. Monney, Thomas Bally, Takuhei Yamamoto, Richard S. GlassElectronic
absorption spectra and quantum chemical calculations
of the radical cations of m-terphenyl tert-butyl thioethers, where the S–t-Bu bond
is forced to be perpendicular to the central phenyl ring, show the
occurrence of through-space [π···S···π]+ bonding interactions which lead to a stabilization of the
thioether radical cations. In the corresponding methyl derivatives
there is a competition between delocalization of the hole that is
centered on a p-AO of the S atom into the π-system of the central
phenyl ring or through space into the flanking phenyl groups, which
leads to a mixture of planar and perpendicular conformations in the
radical cation. Adding a second m-terphenyl tert-butyl thioether moiety does not lead to further delocalization;
the spin and charge remain in one of the two halves of the radical
cation. These findings have interesting implications with regard to
the role of methionines as hopping stations in electron transfer through
proteins.