@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{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{KošćakPeharBožinovićetal.2022,
  author    = {Košćak, Marta and Pehar, Isabela and Božinović, Ksenija and Kole, Goutam Kumar and Sobočanec, Sandra and Podgorski, Iva I. and Pinterić, Marija and M{\"u}ller-Buschbaum, Klaus and Majhen, Dragomira and Piantanida, Ivo and Marder, Todd B.},
  title     = {Para-N-methylpyridinium pyrenes: impact of positive charge on ds-DNA/RNA and protein recognition, photo-induced bioactivity, and intracellular localisation},
  series = {Pharmaceutics},
  volume    = {14},
  journal   = {Pharmaceutics},
  number    = {11},
  issn      = {1999-4923},
  doi       = {10.3390/pharmaceutics14112499},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-297247},
  year      = {2022},
  abstract  = {The 2- and 2,7- substituted para-N-methylpyridinium pyrene cations show high-affinity intercalation into ds-DNAs, whereas their non-methylated analogues interacted with ds-DNA/RNA only in the protonated form (at pH 5), but not at physiological conditions (pH 7). The fluorescence from non-methylated analogues was strongly dependent on the protonation of the pyridines; consequently, they act as fluorescence ratiometric probes for simultaneous detection of both ds-DNA and BSA at pH 5, relying on the ratio between intensities at 420 nm (BSA specific) and 520 nm (DNA specific), whereby exclusively ds-DNA sensing could be switched-off by adjustment to pH 7. Only methylated, permanently charged pyrenes show photoinduced cleavage of circular DNA, attributed to pyrene-mediated irradiation-induced production of singlet oxygen. Consequently, the moderate toxicity of these cations against human cell lines is strongly increased upon irradiation. Detailed studies revealed increased total ROS production in cells treated by the compounds studied, accompanied by cell swelling and augmentation of cellular complexity. The most photo-active 2-para-N-methylpyridinium pyrene showed significant localization at mitochondria, its photo-bioactivity likely due to mitochondrial DNA damage. Other derivatives were mostly non-selectively distributed between various cytoplasmic organelles, thus being less photoactive.},
  language  = {en}
}
@article{GmachBathePetersTeluguetal.2022,
  author    = {Gmach, Philipp and Bathe-Peters, Marc and Telugu, Narasimha and Miller, Duncan C. and Annibale, Paolo},
  title     = {Fluorescence spectroscopy of low-level endogenous β-adrenergic receptor expression at the plasma membrane of differentiating human iPSC-derived cardiomyocytes},
  series = {International Journal of Molecular Sciences},
  volume    = {23},
  journal   = {International Journal of Molecular Sciences},
  number    = {18},
  issn      = {1422-0067},
  doi       = {10.3390/ijms231810405},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-288277},
  year      = {2022},
  abstract  = {The potential of human-induced pluripotent stem cells (hiPSCs) to be differentiated into cardiomyocytes (CMs) mimicking adult CMs functional morphology, marker genes and signaling characteristics has been investigated since over a decade. The evolution of the membrane localization of CM-specific G protein-coupled receptors throughout differentiation has received, however, only limited attention to date. We employ here advanced fluorescent spectroscopy, namely linescan Fluorescence Correlation Spectroscopy (FCS), to observe how the plasma membrane abundance of the β\(_1\)- and β\(_2\)-adrenergic receptors (β\(_{1/2}\)-ARs), labelled using a bright and photostable fluorescent antagonist, evolves during the long-term monolayer culture of hiPSC-derived CMs. We compare it to the kinetics of observed mRNA levels in wildtype (WT) hiPSCs and in two CRISPR/Cas9 knock-in clones. We conduct these observations against the backdrop of our recent report of cell-to-cell expression variability, as well as of the subcellular localization heterogeneity of β-ARs in adult CMs.},
  language  = {en}
}
@article{WildervanckHechtNowakKrol2022,
  author    = {Wildervanck, Martijn J. and Hecht, Reinhard and Nowak-Kr{\´o}l, Agnieszka},
  title     = {Synthesis and strong solvatochromism of push-pull thienylthiazole boron complexes},
  series = {Molecules},
  volume    = {27},
  journal   = {Molecules},
  number    = {17},
  issn      = {1420-3049},
  doi       = {10.3390/molecules27175510},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-286186},
  year      = {2022},
  abstract  = {The solvatochromic behavior of two donor-π bridge-acceptor (D-π-A) compounds based on the 2-(3-boryl-2-thienyl)thiazole π-linker and indandione acceptor moiety are investigated. DFT/TD-DFT calculations were performed in combination with steady-state absorption and emission measurements, along with electrochemical studies, to elucidate the effect of two different strongly electron-donating hydrazonyl units on the solvatochromic and fluorescence behavior of these compounds. The Lippert-Mataga equation was used to estimate the change in dipole moments (Δµ) between ground and excited states based on the measured spectroscopic properties in solvents of varying polarity with the data being supported by theoretical studies. The two asymmetrical D-π-A molecules feature strong solvatochromic shifts in fluorescence of up to ~4300 cm\(^{-1}\) and a concomitant change of the emission color from yellow to red. These changes were accompanied by an increase in Stokes shift to reach values as large as ~5700-5800 cm\(^{-1}\). Quantum yields of ca. 0.75 could be observed for the N,N-dimethylhydrazonyl derivative in nonpolar solvents, which gradually decreased along with increasing solvent polarity, as opposed to the consistently reduced values obtained for the N,N-diphenylhydrazonyl derivative of up to ca. 0.20 in nonpolar solvents. These two push-pull molecules are contrasted with a structurally similar acceptor-π bridge-acceptor (A-π-A) compound.},
  language  = {en}
}
@article{FullWoelflickRadackietal.2022,
  author    = {Full, Felix and W{\"o}lflick, Quentin and Radacki, Krzysztof and Braunschweig, Holger and Nowak-Kr{\´o}l, Agnieszka},
  title     = {Enhanced Optical Properties of Azaborole Helicenes by Lateral and Helical Extension},
  series = {Chemistry - A European Journal},
  volume    = {28},
  journal   = {Chemistry - A European Journal},
  number    = {62},
  doi       = {10.1002/chem.202202280},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-293671},
  year      = {2022},
  abstract  = {The synthesis and characterization of laterally extended azabora[5]-, -[6]- and -[7]helicenes, assembled from N-heteroaromatic and dibenzo[g,p]chrysene building blocks is described. Formally, the π-conjugated systems of the pristine azaborole helicenes were enlarged with a phenanthrene unit leading to compounds with large Stokes shifts, significantly enhanced luminescence quantum yields (Φ) and dissymmetry factors (g\(_{lum}\)). The beneficial effect on optical properties was also observed for helical elongation. The combined contributions of lateral and helical extensions resulted in a compound showing green emission with Φ of 0.31 and |g\(_{lum}\)| of 2.2×10\(^{-3}\), highest within the series of π-extended azaborahelicenes and superior to emission intensity and chiroptical response of its non-extended congener. This study shows that helical and lateral extensions of π-conjugated systems are viable strategies to improve features of azaborole helicenes. In addition, single crystal X-ray analysis of configurationally stable [6]- and -[7]helicenes was used to provide insight into their packing arrangements.},
  language  = {en}
}
@article{BanKaračićTomićetal.2021,
  author    = {Ban, Željka and Karačić, Zrinka and Tomić, Sanja and Amini, Hashem and Marder, Todd B. and Piantanida, Ivo},
  title     = {Triarylborane dyes as a novel non-covalent and non-inhibitive fluorimetric markers for DPP III enzyme},
  series = {Molecules},
  volume    = {26},
  journal   = {Molecules},
  number    = {16},
  issn      = {1420-3049},
  doi       = {10.3390/molecules26164816},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-245046},
  year      = {2021},
  abstract  = {Novel dyes were prepared by simple "click CuAAC" attachment of a triarylborane-alkyne to the azide side chain of an amino acid yielding triarylborane dye 1 which was conjugated with pyrene (dye 2) forming a triarylborane-pyrene FRET pair. In contrast to previous cationic triarylboranes, the novel neutral dyes interact only with proteins, while their affinity to DNA/RNA is completely abolished. Both the reference triarylborane amino acid and triarylborane-pyrene conjugate bind to BSA and the hDPP III enzyme with high affinities, exhibiting a strong (up to 100-fold) fluorescence increase, whereby the triarylborane-pyrene conjugate additionally retained FRET upon binding to the protein. Furthermore, the triarylborane dyes, upon binding to the hDPP III enzyme, did not impair its enzymatic activity under a wide range of experimental conditions, thus being the first non-covalent fluorimetric markers for hDPP III, also applicable during enzymatic reactions with hDPP III substrates.},
  language  = {en}
}
@article{SchulzWuerthner2022,
  author    = {Schulz, Alexander and W{\"u}rthner, Frank},
  title     = {Folding-induced fluorescence enhancement in a series of merocyanine hetero-folda-trimers},
  series = {Angewandte Chemie International Edition},
  volume    = {61},
  journal   = {Angewandte Chemie International Edition},
  number    = {2},
  doi       = {10.1002/anie.202114667},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-256582},
  year      = {2022},
  abstract  = {Many dyes suffer from fast non-radiative decay pathways, thereby showing only short-lived excited states and weak photoluminescence. Here we show a pronounced fluorescence enhancement for a weakly fluorescent merocyanine (MC) dye by being co-facially stacked to other dyes in hetero-folda-trimer architectures. By means of fluorescence spectroscopy (lifetime, quantum yield) the fluorescence enhancement was explained by the rigidification of the emitting chromophore in the defined foldamer architecture and the presence of a non-forbidden lowest exciton state in H-coupled hetero-aggregates. This folding-induced fluorescence enhancement (FIFE) for specific sequences of π-stacked dyes points at a viable strategy toward improved fluorophores that relates to the approach used by nature in the green fluorescent protein (GFP).},
  language  = {en}
}
@article{GriesbeckMichailRauchetal.2019,
  author    = {Griesbeck, Stefanie and Michail, Evripidis and Rauch, Florian and Ogasawara, Hiroaki and Wang, Chenguang and Sato, Yoshikatsu and Edkins, Robert M. and Zhang, Zuolun and Taki, Masayasu and Lambert, Christoph and Yamaguchi, Shigehiro and Marder, Todd B.},
  title     = {The Effect of Branching on the One- and Two-Photon Absorption, Cell Viability, and Localization of Cationic Triarylborane Chromophores with Dipolar versus Octupolar Charge Distributions for Cellular Imaging},
  series = {Chemistry - A European Journal},
  volume    = {25},
  journal   = {Chemistry - A European Journal},
  number    = {57},
  doi       = {10.1002/chem.201902461},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-212887},
  pages     = {13164 -- 13175},
  year      = {2019},
  abstract  = {Two different chromophores, namely a dipolar and an octupolar system, were prepared and their linear and nonlinear optical properties as well as their bioimaging capabilities were compared. Both contain triphenylamine as the donor and a triarylborane as the acceptor, the latter modified with cationic trimethylammonio groups to provide solubility in aqueous media. The octupolar system exhibits a much higher two-photon brightness, and also better cell viability and enhanced selectivity for lysosomes compared with the dipolar chromophore. Furthermore, both dyes were applied in two-photon excited fluorescence (TPEF) live-cell imaging.},
  language  = {en}
}
@article{FullPanchalGoetzetal.2021,
  author    = {Full, Julian and Panchal, Santosh P. and G{\"o}tz, Julian and Krause, Ana-Maria and Nowak-Kr{\´o}l, Agnieszka},
  title     = {Modular Synthesis of Organoboron Helically Chiral Compounds: Cutouts from Extended Helices},
  series = {Angewandte Chemie International Edition},
  volume    = {60},
  journal   = {Angewandte Chemie International Edition},
  number    = {8},
  doi       = {10.1002/anie.202014138},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-225775},
  pages     = {4350 -- 4357},
  year      = {2021},
  abstract  = {Two types of helically chiral compounds bearing one and two boron atoms were synthesized by a modular approach. Formation of the helical scaffolds was executed by the introduction of boron to flexible biaryl and triaryl derived from small achiral building blocks. All-ortho-fused azabora[7]helicenes feature exceptional configurational stability, blue or green fluorescence with quantum yields (Φ\(_{fl}\)) of 18-24 \% in solution, green or yellow solid-state emission (Φ\(_{fl}\) up to 23 \%), and strong chiroptical response with large dissymmetry factors of up to 1.12×10\(^{-2}\). Azabora[9]helicenes consisting of angularly and linearly fused rings are blue emitters exhibiting Φ\(_{fl}\) of up to 47 \% in CH\(_{2}\)Cl\(_{2}\) and 25 \% in the solid state. As revealed by the DFT calculations, their P-M interconversion pathway is more complex than that of H1. Single-crystal X-ray analysis shows clear differences in the packing arrangement of methyl and phenyl derivatives. These molecules are proposed as primary structures of extended helices.},
  language  = {en}
}
@article{MahlShoyamaKrauseetal.2020,
  author    = {Mahl, Magnus and Shoyama, Kazutaka and Krause, Ana-Maria and Schmidt, David and W{\"u}rthner, Frank},
  title     = {Base-Assisted Imidization: A Synthetic Method for the Introduction of Bulky Imide Substituents to Control Packing and Optical Properties of Naphthalene and Perylene Imides},
  series = {Angewandte Chemie International Edition},
  volume    = {59},
  journal   = {Angewandte Chemie International Edition},
  number    = {32},
  doi       = {10.1002/anie.202004965},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218246},
  pages     = {13401 -- 13405},
  year      = {2020},
  abstract  = {We report the direct imidization of naphthalene and perylene dicarboxylic anhydrides/esters with bulky ortho,ortho-diaryl- and ortho,ortho-dialkynylaniline derivatives. This imidization method uses n-butyllithium as a strong base to increase the reactivity of bulky amine derivatives, proceeds under mild reaction conditions, requires only stoichiometric amounts of reactants and gives straightforward access to new sterically crowded rylene dicarboximides. Mechanistic investigations suggest an isoimide as intermediary product, which was converted to the corresponding imide upon addition of an aqueous base. Single-crystal X-ray diffraction analyses reveal dimeric packing motifs for monoimides, while two-side shielded bisimides crystallize in isolated molecules without close π-π-interactions. Spectroscopic investigations disclose the influence of the bulky substituents on the optical properties in the solid state.},
  language  = {en}
}
@article{StolteHechtXieetal.2020,
  author    = {Stolte, Matthias and Hecht, Reinhard and Xie, Zengqi and Liu, Linlin and Kaufmann, Christina and Kudzus, Astrid and Schmidt, David and W{\"u}rthner, Frank},
  title     = {Crystal Engineering of 1D Exciton Systems Composed of Single- and Double-Stranded Perylene Bisimide J-Aggregates},
  series = {Advanced Optical Materials},
  volume    = {8},
  journal   = {Advanced Optical Materials},
  number    = {18},
  doi       = {10.1002/adom.202000926},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218221},
  year      = {2020},
  abstract  = {Single crystals of three at bay area tetraphenoxy-substituted perylene bisimide dyes are grown by vacuum sublimation. X-ray analysis reveals the self-assembly of these highly twisted perylene bisimides (PBIs) in the solid state via imide-imide hydrogen bonding into hydrogen-bonded PBI chains. The crystallographic insights disclose that the conformation and sterical congestion imparted by the phenoxy substituents can be controlled by ortho-substituents. Accordingly, whilst sterically less demanding methyl and isopropyl substituents afford double-stranded PBI chains of complementary P and M atropo-enantiomers, single hydrogen-bonded chains of homochiral PBIs are observed for the sterically more demanding ortho-phenyl substituents. Investigation of the absorption and fluorescence properties of microcrystals and thin films of these PBIs allow for an unambiguous interpretation of these exciton systems. Thus, the J-aggregates of the double-stranded crystals exhibit a much larger (negative) exciton coupling than the single-stranded one, which in contrast has the higher solid-state fluorescence quantum yield.},
  language  = {en}
}
@article{RauchFuchsFriedrichetal.2020,
  author    = {Rauch, Florian and Fuchs, Sonja and Friedrich, Alexandra and Sieh, Daniel and Krummenacher, Ivo and Braunschweig, Holger and Finze, Maik and Marder, Todd B.},
  title     = {Highly Stable, Readily Reducible, Fluorescent, Trifluoromethylated 9-Borafluorenes},
  series = {Chemistry - A European Journal},
  volume    = {26},
  journal   = {Chemistry - A European Journal},
  number    = {56},
  doi       = {10.1002/chem.201905559},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218390},
  pages     = {12794 -- 12808},
  year      = {2020},
  abstract  = {Three different perfluoroalkylated borafluorenes (\(^{F}\)Bf) were prepared and their electronic and photophysical properties were investigated. The systems have four trifluoromethyl moieties on the borafluorene moiety as well as two trifluoromethyl groups at the ortho positions of their exo-aryl moieties. They differ with regard to the para substituents on their exo-aryl moieties, being a proton \(^{F}\)Xyl\(^{F}\)Bf, \(^{F}\)Xyl: 2,6-bis(trifluoromethyl)phenyl), a trifluoromethyl group (\(^{F}\)Mes\(^{F}\)Bf, \(^{F}\)Mes: 2,4,6-tris(trifluoromethyl)phenyl) or a dimethylamino group (p-NMe\(_{2}\)-\(^{F}\)Xyl\(^{F}\)Bf, p-NMe\(_{2}\)-\(^{F}\)Xyl: 4-(dimethylamino)-2,6-bis(trifluoromethyl)phenyl), respectively. All derivatives exhibit extraordinarily low reduction potentials, comparable to those of perylenediimides. The most electron-deficient derivative \(^{F}\)Mes\(^{F}\)Bf was also chemically reduced and its radical anion isolated and characterized. Furthermore, all compounds exhibit very long fluorescent lifetimes of about 250 ns up to 1.6 μs; however, the underlying mechanisms responsible for this differ. The donor-substituted derivative p-NMe\(_{2}\)-\(^{F}\)Xyl\(^{F}\)Bf exhibits thermally activated delayed fluorescence (TADF) from a charge-transfer (CT) state, whereas the \(^{F}\)Mes\(^{F}\)Bf and FXylFBf borafluorenes exhibit only weakly allowed locally excited (LE) transitions due to their symmetry and low transition-dipole moments.},
  language  = {en}
}
@article{PeissertSauerGrabarczyketal.2020,
  author    = {Peissert, Stefan and Sauer, Florian and Grabarczyk, Daniel B. and Braun, Cathy and Sander, Gudrun and Poterszman, Arnaud and Egly, Jean-Marc and Kuper, Jochen and Kisker, Caroline},
  title     = {In TFIIH the Arch domain of XPD is mechanistically essential for transcription and DNA repair},
  series = {Nature Communications},
  volume    = {11},
  journal   = {Nature Communications},
  number    = {1},
  doi       = {10.1038/s41467-020-15241-9},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229857},
  year      = {2020},
  abstract  = {The XPD helicase is a central component of the general transcription factor TFIIH which plays major roles in transcription and nucleotide excision repair (NER). Here we present the high-resolution crystal structure of the Arch domain of XPD with its interaction partner MAT1, a central component of the CDK activating kinase complex. The analysis of the interface led to the identification of amino acid residues that are crucial for the MAT1-XPD interaction. More importantly, mutagenesis of the Arch domain revealed that these residues are essential for the regulation of (i) NER activity by either impairing XPD helicase activity or the interaction of XPD with XPG; (ii) the phosphorylation of the RNA polymerase II and RNA synthesis. Our results reveal how MAT1 shields these functionally important residues thereby providing insights into how XPD is regulated by MAT1 and defining the Arch domain as a major mechanistic player within the XPD scaffold.},
  language  = {en}
}
@article{VermaSteinbacherSchmiedeletal.2016,
  author    = {Verma, Pramod Kumar and Steinbacher, Andreas and Schmiedel, Alexander and Nuernberger, Patrick and Brixner, Tobias},
  title     = {Excited-state intramolecular proton transfer of 2-acetylindan-1,3-dione studied by ultrafast absorption and fluorescence spectroscopy},
  series = {Structural Dynamics},
  volume    = {3},
  journal   = {Structural Dynamics},
  doi       = {10.1063/1.4937363},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-181301},
  year      = {2016},
  abstract  = {We employ transient absorption from the deep-UV to the visible region and fluorescence upconversion to investigate the photoinduced excited-state intramolecular proton-transfer dynamics in a biologically relevant drug molecule, 2-acetylindan-1,3-dione. The molecule is a ß-diketone which in the electronic ground state exists as exocyclic enol with an intramolecular H-bond. Upon electronic excitation at 300 nm, the first excited state of the exocyclic enol is initially populated, followed by ultrafast proton transfer (≈160 fs) to form the vibrationally hot endocyclic enol. Subsequently, solvent-induced vibrational relaxation takes place (≈10 ps) followed by decay (≈390 ps) to the corresponding ground state.},
  language  = {en}
}
@article{HattoriMichailSchmiedeletal.2019,
  author    = {Hattori, Yohei and Michail, Evripidis and Schmiedel, Alexander and Moos, Michael and Holzapfel, Marco and Krummenacher, Ivo and Braunschweig, Holger and M{\"u}ller, Ulrich and Pflaum, Jens and Lambert, Christoph},
  title     = {Luminescent Mono-, Di-, and Tri-radicals: Bridging Polychlorinated Triarylmethyl Radicals by Triarylamines and Triarylboranes},
  series = {Chemistry - A European Journal},
  volume    = {25},
  journal   = {Chemistry - A European Journal},
  number    = {68},
  doi       = {10.1002/chem.201903007},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-208162},
  pages     = {15463-15471},
  year      = {2019},
  abstract  = {Up to three polychlorinated pyridyldiphenylmethyl radicals bridged by a triphenylamine carrying electron withdrawing (CN), neutral (Me), or donating (OMe) groups were synthesized and analogous radicals bridged by tris(2,6-dimethylphenyl)borane were prepared for comparison. All compounds were as stable as common closed-shell organic compounds and showed significant fluorescence upon excitation. Electronic, magnetic, absorption, and emission properties were examined in detail, and experimental results were interpreted using DFT calculations. Oxidation potentials, absorption and emission energies could be tuned depending on the electron density of the bridges. The triphenylamine bridges mediated intramolecular weak antiferromagnetic interactions between the radical spins, and the energy difference between the high spin and low spin states was determined by temperature dependent ESR spectroscopy and DFT calculations. The fluorescent properties of all radicals were examined in detail and revealed no difference for high and low spin states which facilitates application of these dyes in two-photon absorption spectroscopy and OLED devices.},
  language  = {en}
}
@article{BossertdeBruinGoetzetal.2016,
  author    = {Bossert, Nelli and de Bruin, Donny and G{\"o}tz, Maria and Bouwmeester, Dirk and Heinrich, Doris},
  title     = {Fluorescence-tunable Ag-DNA biosensor with tailored cytotoxicity for live-cell applications},
  series = {Scientific Reports},
  volume    = {6},
  journal   = {Scientific Reports},
  number    = {37897},
  doi       = {10.1038/srep37897},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-167482},
  year      = {2016},
  abstract  = {DNA-stabilized silver clusters (Ag-DNA) show excellent promise as a multi-functional nanoagent for molecular investigations in living cells. The unique properties of these fluorescent nanomaterials allow for intracellular optical sensors with tunable cytotoxicity based on simple modifications of the DNA sequences. Three Ag-DNA nanoagent designs are investigated, exhibiting optical responses to the intracellular environments and sensing-capability of ions, functional inside living cells. Their sequence-dependent fluorescence responses inside living cells include (1) a strong splitting of the fluorescence peak for a DNA hairpin construct, (2) an excitation and emission shift of up to 120 nm for a single-stranded DNA construct, and (3) a sequence robust in fluorescence properties. Additionally, the cytotoxicity of these Ag-DNA constructs is tunable, ranging from highly cytotoxic to biocompatible Ag-DNA, independent of their optical sensing capability. Thus, Ag-DNA represents a versatile live-cell nanoagent addressable towards anti-cancer, patient-specific and anti-bacterial applications.},
  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}
}
@article{DietzHasseFerrarisetal.2013,
  author    = {Dietz, Mariana S. and Hasse, Daniel and Ferraris, Davide M. and G{\"o}hler, Antonia and Niemann, Hartmut H. and Heilemann, Mike},
  title     = {Single-molecule photobleaching reveals increased MET receptor dimerization upon ligand binding in intact cells},
  series = {BMC Biophysics},
  volume    = {6},
  journal   = {BMC Biophysics},
  number    = {6},
  issn      = {2046-1682},
  doi       = {10.1186/2046-1682-6-6},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121835},
  year      = {2013},
  abstract  = {Background: The human receptor tyrosine kinase MET and its ligand hepatocyte growth factor/scatter factor are essential during embryonic development and play an important role during cancer metastasis and tissue regeneration. In addition, it was found that MET is also relevant for infectious diseases and is the target of different bacteria, amongst them Listeria monocytogenes that induces bacterial uptake through the surface protein internalin B. Binding of ligand to the MET receptor is proposed to lead to receptor dimerization. However, it is also discussed whether preformed MET dimers exist on the cell membrane. Results: To address these issues we used single-molecule fluorescence microscopy techniques. Our photobleaching experiments show that MET exists in dimers on the membrane of cells in the absence of ligand and that the proportion of MET dimers increases significantly upon ligand binding. Conclusions: Our results indicate that partially preformed MET dimers may play a role in ligand binding or MET signaling. The addition of the bacterial ligand internalin B leads to an increase of MET dimers which is in agreement with the model of ligand-induced dimerization of receptor tyrosine kinases.},
  language  = {en}
}
@article{FosterEdkinsCameronetal.2014,
  author    = {Foster, Jonathan A. and Edkins, Robert M. and Cameron, Gary J. and Colgin, Neil and Fucke, Katharina and Ridgeway, Sam and Crawford, Andrew G. and Marder, Todd B. and Beeby, Andrew and Cobb, Steven L. and Steed, Jonathan W.},
  title     = {Blending Gelators to Tune Gel Structure and Probe Anion-Induced Disassembly},
  series = {Chemistry : A European Journal},
  volume    = {20},
  journal   = {Chemistry : A European Journal},
  doi       = {10.1002/chem.201303153},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121141},
  pages     = {279-91},
  year      = {2014},
  abstract  = {Blending different low molecular weight gelators (LMWGs) provides a convenient route to tune the properties of a gel and incorporate functionalities such as fluorescence. Blending a series of gelators having a common bis-urea motif, and functionalised with different amino acid-derived end-groups and differing length alkylene spacers is reported. Fluorescent gelators incorporating 1- and 2-pyrenyl moieties provide a probe of the mixed systems alongside structural and morphological data from powder diffraction and electron microscopy. Characterisation of the individual gelators reveals that although the expected α-urea tape motif is preserved, there is considerable variation in the gelation properties, molecular packing, fibre morphology and rheological behaviour. Mixing of the gelators revealed examples in which: 1) the gels formed separate, orthogonal networks maintaining their own packing and morphology, 2) the gels blended together into a single network, either adopting the packing and morphology of one gelator, or 3) a new structure not seen for either of the gelators individually was created. The strong binding of the urea functionalities to anions was exploited as a means of breaking down the gel structure, and the use of fluorescent gel blends provides new insights into anion-mediated gel dissolution.},
  language  = {en}
}