@article{MerzDietzVonhausenetal.2020, author = {Merz, Julia and Dietz, Maximilian and Vonhausen, Yvonne and W{\"o}ber, Frederik and Friedrich, Alexandra and Sieh, Daniel and Krummenacher, Ivo and Braunschweig, Holger and Moos, Michael and Holzapfel, Marco and Lambert, Christoph and Marder, Todd B.}, title = {Synthesis, Photophysical and Electronic Properties of New Red-to-NIR Emitting Donor-Acceptor Pyrene Derivatives}, series = {Chemistry - A European Journal}, volume = {26}, journal = {Chemistry - A European Journal}, number = {2}, doi = {10.1002/chem.201904219}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-207486}, pages = {438-453}, year = {2020}, abstract = {We synthesized new pyrene derivatives with strong bis(para -methoxyphenyl)amine donors at the 2,7-positions and n -azaacene acceptors at the K-region of pyrene. The compounds possess a strong intramolecular charge transfer, leading to unusual properties such as emission in the red to NIR region (700 nm), which has not been reported before for monomeric pyrenes. Detailed photophysical studies reveal very long intrinsic lifetimes of >100 ns for the new compounds, which is typical for 2,7-substituted pyrenes but not for K-region substituted pyrenes. The incorporation of strong donors and acceptors leads to very low reduction and oxidation potentials, and spectroelectrochemical studies show that the compounds are on the borderline between localized Robin-Day class-II and delocalized Robin-Day class-III species.}, language = {en} } @article{MerzDietrichNitschetal.2020, author = {Merz, Julia and Dietrich, Lena and Nitsch, J{\"o}rn and Krummenacher, Ivo and Braunschweig, Holger and Moos, Michael and Mims, David and Lambert, Christoph and Marder, Todd B.}, title = {Synthesis, Photophysical and Electronic Properties of Mono-, Di-, and Tri-Amino-Substituted Ortho-Perylenes, and Comparison to the Tetra-Substituted Derivative}, series = {Chemistry - A European Journal}, volume = {26}, journal = {Chemistry - A European Journal}, number = {52}, doi = {10.1002/chem.202001475}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-217835}, pages = {12050 -- 12059}, year = {2020}, abstract = {We synthesized a series of new mono-, di-, tri- and tetra-substituted perylene derivatives with strong bis(para-methoxyphenyl)amine (DPA) donors at the uncommon 2,5,8,11-positions. The properties of our new donor-substituted perylenes were studied in detail to establish a structure-property relationship. Interesting trends and unusual properties are observed for this series of new perylene derivatives, such as a decreasing charge transfer (CT) character with increasing number of DPA moieties and individual reversible oxidations for each DPA moiety. Thus, (DPA)-Per possesses one reversible oxidation while (DPA)\(_{4}\)-Per has four. The mono- and di-substituted derivatives display unusually large Stokes shifts not previously reported for perylenes. Furthermore, transient absorption measurements of the new derivatives reveal an excited state with lifetimes of several hundred microseconds, which sensitizes singlet oxygen with quantum yields of up to 0.83.}, language = {en} } @article{MerzMerzKirchneretal.2021, author = {Merz, Viktor and Merz, Julia and Kirchner, Maximilian and Lenhart, Julian and Marder, Todd B. and Krueger, Anke}, title = {Pyrene-Based "Turn-Off" Probe with Broad Detection Range for Cu\(^{2+}\), Pb\(^{2+}\) and Hg\(^{2+}\) Ions}, series = {Chemistry—A European Journal}, volume = {27}, journal = {Chemistry—A European Journal}, number = {31}, doi = {10.1002/chem.202100594}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-256803}, pages = {8118-8126}, year = {2021}, abstract = {Detection of metals in different environments with high selectivity and specificity is one of the prerequisites of the fight against environmental pollution with these elements. Pyrenes are well suited for the fluorescence sensing in different media. The applied sensing principle typically relies on the formation of intra- and intermolecular excimers, which is however limiting the sensitivity range due to masking of e. g. quenching effects by the excimer emission. Herein we report a highly selective, structurally rigid chemical sensor based on the monomer fluorescence of pyrene moieties bearing triazole groups. This sensor can quantitatively detect Cu\(^{2+}\), Pb\(^{2+}\) and Hg\(^{2+}\) in organic solvents over a broad concentrations range, even in the presence of ubiquitous ions such as Na\(^{+}\), K\(^{+}\), Ca\(^{2+}\) and Mg\(^{2+}\). The strongly emissive sensor's fluorescence with a long lifetime of 165 ns is quenched by a 1 : 1 complex formation upon addition of metal ions in acetonitrile. Upon addition of a tenfold excess of the metal ion to the sensor, agglomerates with a diameter of about 3 nm are formed. Due to complex interactions in the system, conventional linear correlations are not observed for all concentrations. Therefore, a critical comparison between the conventional Job plot interpretation, the method of Benesi-Hildebrand, and a non-linear fit is presented. The reported system enables the specific and robust sensing of medically and environmentally relevant ions in the health-relevant nM range and could be used e. g. for the monitoring of the respective ions in waste streams.}, language = {en} }