@article{RennerMahlmeisterAnhaltetal.2021,
  author    = {Renner, Rebecca and Mahlmeister, Bernhard and Anhalt, Olga and Stolte, Matthias and W{\"u}rthner, Frank},
  title     = {Chiral Perylene Bisimide Dyes by Interlocked Arene Substituents in the Bay Area},
  series = {Chemistry - A European Journal},
  volume    = {27},
  journal   = {Chemistry - A European Journal},
  number    = {46},
  doi       = {10.1002/chem.202101877},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-249070},
  pages     = {11997 -- 12006},
  year      = {2021},
  abstract  = {A series of perylene bisimide (PBI) dyes bearing various aryl substituents in 1,6,7,12 bay positions has been synthesized by Suzuki cross-coupling reaction. These molecules exhibit an exceptionally large and conformationally fixed twist angle of the PBI π-core due to the high steric congestion imparted by the aryl substituents in bay positions. Single crystal X-ray analyses of phenyl-, naphthyl- and pyrenyl-functionalized PBIs reveal interlocked π-π-stacking motifs, leading to conformational chirality and the possibility for the isolation of enantiopure atropoisomers by semipreparative HPLC. The interlocked arrangement endows these molecules with substantial racemization barriers of about 120 kJ mol\(^{-1}\) for the tetraphenyl- and tetra-2-naphthyl-substituted derivatives, which is among the highest racemization barriers for axially chiral PBIs. Variable temperature NMR studies reveal the presence of a multitude of up to fourteen conformational isomers in solution that are interconverted via smaller activation barriers of about 65 kJ mol\(^{-1}\). The redox and optical properties of these core-twisted PBIs have been characterized by cyclic voltammetry, UV/Vis/NIR and fluorescence spectroscopy and their respective atropo-enantiomers were further characterized by circular dichroism (CD) and circular polarized luminescence (CPL) spectroscopy.},
  language  = {en}
}
@article{SunAnhaltSarosietal.2022,
  author    = {Sun, Meng-Jia and Anhalt, Olga and S{\´a}rosi, Menyh{\´a}rt B. and Stolte, Matthias and W{\"u}rthner, Frank},
  title     = {Activating Organic Phosphorescence via Heavy Metal-π Interaction Induced Intersystem Crossing},
  series = {Advanced Materials},
  volume    = {34},
  journal   = {Advanced Materials},
  number    = {51},
  doi       = {10.1002/adma.202207331},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312248},
  year      = {2022},
  abstract  = {Heavy-atom-containing clusters, nanocrystals, and other semiconductors can sensitize the triplet states of their surface-bonded chromophores, but the energy loss, such as nonradiative deactivation, often prevents the synergistic light emission in their solid-state coassemblies. Cocrystallization allows new combinations of molecules with complementary properties for achieving functionalities not available in single components. Here, the cocrystal formation that employs platinum(II) acetylacetonate (Pt(acac)\(_{2}\)) as a triplet sensitizer and electron-deficient 1,4,5,8-naphthalene diimides (NDIs) as organic phosphors is reported. The hybrid cocrystals exhibit room-temperature phosphorescence confined in the low-lying, long-lived triplet state of NDIs with photoluminescence (PL) quantum yield (Φ\(_{PL}\)) exceeding 25\% and a phosphorescence lifetime (τ\(_{Ph}\)) of 156 µs. This remarkable PL property benefits from the noncovalent electronic and spin-orbital coupling between the constituents.},
  language  = {en}
}