@article{KirchnerSchrammIvanovaetal.2024,
  author    = {Kirchner, Philipp H. and Schramm, Louis and Ivanova, Svetlana and Shoyama, Kazutaka and W{\"u}rthner, Frank and Beuerle, Florian},
  title     = {A water-stable boronate ester cage},
  series = {Journal of the American Chemical Society},
  volume    = {146},
  journal   = {Journal of the American Chemical Society},
  number    = {8},
  issn      = {0002-7863},
  doi       = {10.1021/jacs.3c12002},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-361245},
  pages     = {5305-5315},
  year      = {2024},
  abstract  = {The reversible condensation of catechols and boronic acids to boronate esters is a paradigm reaction in dynamic covalent chemistry. However, facile backward hydrolysis is detrimental for stability and has so far prevented applications for boronate-based materials. Here, we introduce cubic boronate ester cages 6 derived from hexahydroxy tribenzotriquinacenes and phenylene diboronic acids with ortho-t-butyl substituents. Due to steric shielding, dynamic exchange at the Lewis acidic boron sites is feasible only under acid or base catalysis but fully prevented at neutral conditions. For the first time, boronate ester cages 6 tolerate substantial amounts of water or alcohols both in solution and solid state. The unprecedented applicability of these materials under ambient and aqueous conditions is showcased by efficient encapsulation and on-demand release of β-carotene dyes and heterogeneous water oxidation catalysis after the encapsulation of ruthenium catalysts.},
  language  = {en}
}
@article{SungKimFimmeletal.2015,
  author    = {Sung, Jooyoung and Kim, Pyosang and Fimmel, Benjamin and W{\"u}rthner, Frank and Kim, Dongho},
  title     = {Direct observation of ultrafast coherent exciton dynamics in helical π-stacks of self-assembled perylene bisimides},
  series = {Nature Communications},
  volume    = {6},
  journal   = {Nature Communications},
  number    = {8646},
  doi       = {10.1038/ncomms9646},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148157},
  year      = {2015},
  abstract  = {Ever since the discovery of dye self-assemblies in nature, there have been tremendous efforts to exploit biomimetic supramolecular assemblies for tailored artificial photon processing materials. This feature necessarily has resulted in an increasing demand for understanding exciton dynamics in the dye self-assemblies. In a sharp contrast with pi-type aggregates, however, the detailed observation of exciton dynamics in H-type aggregates has remained challenging. In this study, as we succeed in measuring transient fluorescence from Frenkel state of π-stacked perylene tetracarboxylic acid bisimide dimer and oligomer aggregates, we present an experimental demonstration on Frenkel exciton dynamics of archetypal columnar π-π stacks of dyes. The analysis of the vibronic peak ratio of the transient fluorescence spectra reveals that unlike the simple π-stacked dimer, the photoexcitation energy in the columnar π-stacked oligomer aggregates is initially delocalized over at least three molecular units and moves coherently along the chain in tens of femtoseconds, preceding excimer formation process.},
  language  = {en}
}