@phdthesis{Muetzel2024,
  author    = {M{\"u}tzel, Carina},
  title     = {Low-LUMO Boron-Doped Polycyclic Aromatic Hydrocarbons},
  doi       = {10.25972/OPUS-28700},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-287004},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2024},
  abstract  = {Within this PhD thesis, starting from simple alkene precursors a series of novel boron-doped PAHs were successfully in a sequential one-pot synthetic approach, comprising a hydroboration/borylation cascade as the key step. By applying different postsynthetic reactions, the properties of these boron-doped PAHs were further adjusted, aiming for appealing packing motifs, strong electron-acceptors, and NIR-emitters. The thesis thereby focussed on the synthesis of tailor-made molecules, the investigation of their optical and electronic properties and the discussion on the influence of various factors, e.g. doping pattern, size, shape, and substituents, on these properties.},
  subject      = {Bor},
  language  = {en}
}
@phdthesis{Zhang2024,
  author    = {Zhang, Fangyuan},
  title     = {Design, Synthesis, and Chiroptical Properties of Functional Chiral Molecules Based on (Aza)[7]helicene},
  doi       = {10.25972/OPUS-37400},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-374002},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2024},
  abstract  = {This thesis focusses on the synthesis of functional chiral molecules using carbo- or hetero[7]helicenes as a chiral element, combined with multiple helicenes, phthalocyanines, and 1,4-azaborine units. The objective is to achieve properties that surpass those of the parent compounds. In the first project, an enantiopure, propeller-shaped multi-helicene polycyclic aromatic hydrocarbon containing three (P)-[7]helicene units and three (M)-[5]helicene units was stereospecifically synthesized and can be obtained in gram quantities. Leveraging the configurational stability of [7]helicene and the configurational instability of [5]helicene, we exclusively obtained the most thermodynamically stable enantiomer out of 10 possible enantiomeric pairs. The effects of the multi-helicene structure on optical rotation, UVVis absorption, fluorescence, and electronic circular dichroism (CD) spectroscopy were investigated.1 Building on the success of the first project, the second project used the configurationally stable [7]helicene again. Zinc-[7]helicenocyanine (Zn-7HPc) was stereospecifically synthesized by directly conjugating [7]helicenes with a phthalocyanine (Pc) core. Zn-7HPc demonstrates a CD signal in the near-infrared region, indicating efficient chirality transfer from the helicenes to the Pc core. Zn-7HPc forms stable, discrete homochiral dimers over a wide range of concentrations in tetrahydrofuran and dimethyl sulfoxide, as well as in the solid state. These homochiral dimers are formed even within the racemic mixture due to the interlocking of two homochiral monomers. The large comproportionation constant and the observed intervalence charge transfer band that appeared in spectroelectrochemistry experiments indicate strong communication between the two Pc monomers in the dimer.2 In the third project, aza[7]helicenes were incorporated with a 1,4-azaborine unit, which exhibits a multiple-resonance effect, to achieve narrow-band emission, high fluorescence quantum yield (FL), and a small Stokes shift. These properties are essential for ultrahigh-definition organic light-emitting diodes that emit circularly polarized light (CP-OLEDs). The synthesized series of molecules demonstrate small Stokes shifts (0.06-0.07 eV), exceptionally narrow fluorescence and circularly polarized luminescence bands with small full width at half maximum (FWHM, 17-28 nm, 0.07-0.13 eV), and high FL (72-85\%).3 In conclusion, the synthesis of functional chiral molecules based on carbo- or hetero[7]helicenes was successfully achieved. The efficient synthetic strategies and improved properties of these molecules provide valuable insights for further investigations into helicenes with advanced structures and enhanced properties.},
  language  = {en}
}
@article{MatarranzGhoshKandanellietal.2021,
  author    = {Matarranz, Beatriz and Ghosh, Goutam and Kandanelli, Ramesh and Sampedro, Angel and Kartha, Kalathil K. and Fern{\´a}ndez, Gustavo},
  title     = {Understanding the role of conjugation length on the self-assembly behaviour of oligophenyleneethynylenes},
  series = {Chemical Communications},
  volume    = {57},
  journal   = {Chemical Communications},
  doi       = {10.1039/d1cc01054a},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-370444},
  pages     = {4890-4893},
  year      = {2021},
  abstract  = {Oligophenyleneethynylenes (OPEs) are prominent building blocks with exciting optical and supramolecular properties. However, their generally small spectroscopic changes upon aggregation make the analysis of their self-assembly challenging, especially in the absence of additional hydrogen bonds. Herein, by investigating a series of OPEs of increasing size, we have unravelled the role of the conjugation length on the self-assembly properties of OPEs.},
  language  = {en}
}
@article{LiTrovatelloDalConteetal.2021,
  author    = {Li, Donghai and Trovatello, Chiara and Dal Conte, Stefano and Nuß, Matthias and Soavi, Giancarlo and Wang, Gang and Ferrari, Andrea C. and Cerullo, Giulio and Brixner, Tobias},
  title     = {Exciton-phonon coupling strength in single-layer MoSe2 at room temperature},
  series = {Nature Communications},
  volume    = {12},
  journal   = {Nature Communications},
  doi       = {10.1038/s41467-021-20895-0},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-363837},
  year      = {2021},
  abstract  = {Single-layer transition metal dichalcogenides are at the center of an ever increasing research effort both in terms of fundamental physics and applications. Exciton-phonon coupling plays a key role in determining the (opto)electronic properties of these materials. However, the exciton-phonon coupling strength has not been measured at room temperature. Here, we use two-dimensional micro-spectroscopy to determine exciton-phonon coupling of single-layer MoSe2. We detect beating signals as a function of waiting time induced by the coupling between A excitons and A′1 optical phonons. Analysis of beating maps combined with simulations provides the exciton-phonon coupling. We get a Huang-Rhys factor ~1, larger than in most other inorganic semiconductor nanostructures. Our technique offers a unique tool to measure exciton-phonon coupling also in other heterogeneous semiconducting systems, with a spatial resolution ~260 nm, and provides design-relevant parameters for the development of optoelectronic devices.},
  language  = {en}
}
@article{BaeumerKarthaKumarAllampallyetal.2019,
  author    = {B{\"a}umer, Nils and Kartha, Kalathil K. and Kumar Allampally, Naveen and Yagai, Shiki and Albuquerque, Rodrigo Q. and Fern{\´a}ndez, Gustavo},
  title     = {Exploiting Coordination Isomerism for Controlled Self-Assembly},
  series = {Angewandte Chemie International Edition},
  volume    = {58},
  journal   = {Angewandte Chemie International Edition},
  doi       = {10.1002/anie.201908002},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-221362},
  pages     = {15626-15630},
  year      = {2019},
  abstract  = {We exploited the inherent geometrical isomerism of a PtII complex as a new tool to control supramolecular assembly processes. UV irradiation and careful selection of solvent, temperature, and concentration leads to tunable coordination isomerism, which in turn allows fully reversible switching between two distinct aggregate species (1D fibers↔2D lamellae) with different photoresponsive behavior. Our findings not only broaden the scope of coordination isomerism, but also open up exciting possibilities for the development of novel stimuli-responsive nanomaterials.},
  language  = {en}
}
@article{SolDehmHechtetal.2018,
  author    = {Sol, Jeroen A. H. P. and Dehm, Volker and Hecht, Reinhard and W{\"u}rthner, Frank and Schenning, Albertus P. H. J. and Debije, Michael G.},
  title     = {Temperature-Responsive Luminescent Solar Concentrators: Tuning Energy Transfer in a Liquid Crystalline Matrix},
  series = {Angewandte Chemie International Edition},
  volume    = {57},
  journal   = {Angewandte Chemie International Edition},
  doi       = {10.1002/anie.201710487},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-238778},
  pages     = {1030-1033},
  year      = {2018},
  abstract  = {Temperature-responsive luminescent solar concentrators (LSCs) have been fabricated in which the F{\"o}rster resonance energy transfer (FRET) between a donor-acceptor pair in a liquid crystalline solvent can be tuned. At room temperatures, the perylene bisimide (PBI) acceptor is aggregated and FRET is inactive; while after heating to a temperature above the isotropic phase of the liquid crystal solvent, the acceptor PBI completely dissolves and FRET is activated. This unusual temperature control over FRET was used to design a color-tunable LSC. The device has been shown to be highly stable towards consecutive heating and cooling cycles, making it an appealing device for harvesting otherwise unused solar energy.},
  language  = {en}
}
@article{GoleStepanenkoRageretal.2018,
  author    = {Gole, Bappaditya and Stepanenko, Vladimir and Rager, Sabrina and Gr{\"u}ne, Matthias and Medina, Dana D. and Bein, Thomas and W{\"u}rthner, Frank and Beuerle, Florian},
  title     = {Microtubular Self-Assembly of Covalent Organic Frameworks},
  series = {Angewandte Chemie International Edition},
  volume    = {57},
  journal   = {Angewandte Chemie International Edition},
  doi       = {10.1002/anie.201708526},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227373},
  pages     = {846-850},
  year      = {2018},
  abstract  = {Despite significant progress in the synthesis of covalent organic frameworks (COFs), reports on the precise construction of template-free nano- and microstructures of such materials have been rare. In the quest for dye-containing porous materials, a novel conjugated framework DPP-TAPP-COF with an enhanced absorption capability up to λ=800 nm has been synthesized by utilizing reversible imine condensations between 5,10,15,20-tetrakis(4-aminophenyl)porphyrin (TAPP) and a diketopyrrolopyrrole (DPP) dialdehyde derivative. Surprisingly, the obtained COF exhibited spontaneous aggregation into hollow microtubular assemblies with outer and inner tube diameters of around 300 and 90 nm, respectively. A detailed mechanistic investigation revealed the time-dependent transformation of initial sheet-like agglomerates into the tubular microstructures.},
  language  = {en}
}
@article{GarainShoyamaGinderetal.2024,
  author    = {Garain, Swadhin and Shoyama, Kazutaka and Ginder, Lea-Marleen and S{\´a}rosi, Menyh{\´a}rt and W{\"u}rthner, Frank},
  title     = {The delayed box: biphenyl bisimide cyclophane, a supramolecular nano-environment for the efficient generation of delayed fluorescence},
  series = {Journal of the American Chemical Society},
  volume    = {146},
  journal   = {Journal of the American Chemical Society},
  number    = {31},
  issn      = {0002-7863},
  doi       = {10.1021/jacs.4c07730},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-370385},
  pages     = {22056-22063},
  year      = {2024},
  abstract  = {Activating delayed fluorescence emission in a dilute solution via a non-covalent approach is a formidable challenge. In this report, we propose a strategy for efficient delayed fluorescence generation in dilute solution using a non-covalent approach via supramolecularly engineered cyclophane-based nanoenvironments that provide sufficient binding strength to π-conjugated guests and that can stabilize triplet excitons by reducing vibrational dissipation and lowering the singlet-triplet energy gap for efficient delayed fluorescence emission. Toward this goal, a novel biphenyl bisimide-derived cyclophane is introduced as an electron-deficient and efficient triplet-generating host. Upon encapsulation of various carbazole-derived guests inside the nanocavity of this cyclophane, emissive charge transfer (CT) states close to the triplet energy level of the biphenyl bisimide are generated. The experimental results of host-guest studies manifest high association constants up to 10\(^4\) M\(^{-1}\) as the prerequisite for inclusion complex formation, the generation of emissive CT states, and triplet-state stabilization in a diluted solution state. By means of different carbazole guest molecules, we could realize tunable delayed fluorescence emission in this carbazole-encapsulated biphenyl bisimide cyclophane in methylcyclohexane/carbon tetrachloride solutions with a quantum yield (QY) of up to 15.6\%. Crystal structure analyses and solid-state photophysical studies validate the conclusions from our solution studies and provide insights into the delayed fluorescence emission mechanism.},
  language  = {en}
}
@article{GryszelSchlossarekWuerthneretal.2023,
  author    = {Gryszel, Maciej and Schlossarek, Tim and W{\"u}rthner, Frank and Natali, Mirco and Głowacki, Eric Daniel},
  title     = {Water-soluble cationic perylene diimide dyes as stable photocatalysts for H\(_2\)O\(_2\) evolution},
  series = {ChemPhotoChem},
  volume    = {7},
  journal   = {ChemPhotoChem},
  number    = {9},
  issn      = {2367-0932},
  doi       = {10.1002/cptc.202300070},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-370250},
  year      = {2023},
  abstract  = {Photocatalytic generation of hydrogen peroxide, H\(_2\)O\(_2\), has gained increasing attention in recent years, with applications ranging from solar energy conversion to biophysical research. While semiconducting solid-state materials are normally regarded as the workhorse for photogeneration of H\(_2\)O\(_2\), an intriguing alternative for on-demand H\(_2\)O\(_2\) is the use of photocatalytic organic dyes. Herein we report the use of water-soluble dyes based on perylene diimide molecules which behave as true molecular catalysts for the light-induced conversion of dissolved oxygen to hydrogen peroxide. In particular, we address how to obtain visible-light photocatalysts which are stable with respect to aggregation and photochemical degradation. We report on the factors affecting efficiency and stability, including variable electron donors, oxygen partial pressure, pH, and molecular catalyst structure. The result is a perylene diimide derivative with unprecedented peroxide evolution performance using a broad range of organic donor molecules and operating in a wide pH range.},
  language  = {en}
}
@article{GilSepulcreLindnerSchindleretal.2021,
  author    = {Gil-Sepulcre, Marcos and Lindner, Joachim O. and Schindler, Dorothee and Velasco, Luc{\´i}a and Moonshiram, Dooshaye and R{\"u}diger, Olaf and DeBeer, Serena and Stepanenko, Vladimir and Solano, Eduardo and W{\"u}rthner, Frank and Llobet, Antoni},
  title     = {Surface-promoted evolution of Ru-bda coordination oligomers boosts the efficiency of water oxidation molecular anodes},
  series = {Journal of the American Chemical Society},
  volume    = {143},
  journal   = {Journal of the American Chemical Society},
  number    = {30},
  doi       = {10.1021/jacs.1c04738},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-351514},
  pages     = {11651-11661},
  year      = {2021},
  abstract  = {A new Ru oligomer of formula {[Ru-\(^{II}\)(bda-\(\kappa\)-N\(^2\)O\(^2\))(4,4'-bpy)]\(_{10}\)(4,4'-bpy)}, 10 (bda is [2,2'-bipyridine]-6,6'-dicarbox-ylate and 4,4'-bpy is 4,4'-bipyridine), was synthesized and thoroughly characterized with spectroscopic, X-ray, and electrochemical techniques. This oligomer exhibits strong affinity for graphitic materials through CH-\(\pi\) interactions and thus easily anchors on multiwalled carbon nanotubes (CNT), generating the molecular hybrid material 10@CNT. The latter acts as a water oxidation catalyst and converts to a new species, 10'(H\(_2\)O)\(_2\)@CNT, during the electrochemical oxygen evolution process involving solvation and ligand reorganization facilitated by the interactions of molecular Ru catalyst and the surface. This heterogeneous system has been shown to be a powerful and robust molecular hybrid anode for electrocatalytic water oxidation into molecular oxygen, achieving current densities in the range of 200 mA/cm\(^2\) at pH 7 under an applied potential of 1.45 V vs NHE. The remarkable long-term stability of this hybrid material during turnover is rationalized based on the supramolecular interaction of the catalyst with the graphitic surface.},
  language  = {en}
}