@unpublished{YinWernerHiguchietal.2018, author = {Yin, Yafu and Werner, Rudolf A. and Higuchi, Takahiro and Lapa, Constantin and Pienta, Kenneth J. and Pomper, Martin G. and Gorin, Michael A. and Rowe, Steven P.}, title = {Follow-Up of Lesions with Equivocal Radiotracer Uptake on PSMA-Targeted PET in Patients with Prostate Cancer: Predictive Values of the PSMA-RADS-3A and PSMARADS- 3B Categories}, series = {Journal of Nuclear Medicine}, journal = {Journal of Nuclear Medicine}, issn = {0161-5505}, doi = {10.2967/jnumed.118.217653}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-167594}, year = {2018}, abstract = {Purpose: Prostate-specific membrane antigen (PSMA)-targeted positron emission tomography (PET) imaging has become commonly utilized in patients with prostate cancer (PCa). The PSMA reporting and data system version 1.0 (PSMA-RADS version 1.0) categorizes lesions on the basis of the likelihood of PCa involvement, with PSMA-RADS-3A (soft tissue) and PSMA-RADS-3B (bone) lesions being indeterminate for the presence of disease. We retrospectively reviewed the imaging follow-up of such lesions to determine the rate at which they underwent changes suggestive of underlying PCa. Methods: PET/CT imaging with \(^{18}\)F-DCFPyL was carried out in 110 patients with PCa and lesions were categorized according to PSMA-RADS Version 1.0. 56/110 (50.9\%) patients were determined to have indeterminate PSMA-RADS-3A or PSMA-RADS-3B lesions and 22/56 (39.3\%) patients had adequate follow-up to be included in the analysis. The maximum standardized uptake values (SUV\(_{max}\)) of the lesions were obtained and the ratios of SUV\(_{max}\) of the lesions to SUV\(_{mean}\) of blood pool (SUV\(_{max}\)-lesion/SUV\(_{mean}\)-bloodpool) were calculated. Pre-determined criteria were used to evaluate the PSMA-RADS-3A and PSMA-RADS-3B lesions on follow-up imaging to determine if they demonstrated evidence of underlying malignancy. Results: A total of 46 lesions in 22 patients were considered indeterminate for PCa (i.e. PSMA-RADS-3A (32 lesions) or PSMA-RADS-3B (14 lesions)) and were evaluable on follow-up imaging. 27/46 (58.7\%) lesions demonstrated changes on follow-up imaging consistent with the presence of underlying PCa at baseline. These lesions included 24/32 (75.0\%) PSMA-RADS-3A lesions and 3/14 (21.4\%) lesions categorized as PSMA-RADS-3B. The ranges of SUVmax and SUVmax-lesion/SUVmean-bloodpool overlapped between those lesions demonstrating changes consistent with malignancy on follow-up imaging and those lesions that remained unchanged on follow-up. Conclusion: PSMA-RADS-3A and PSMA-RADS-3B lesions are truly indeterminate in that proportions of findings in both categories demonstrate evidence of malignancy on follow-up imaging. Overall, PSMA-RADS-3A lesions are more likely than PSMA-RADS-3B lesions to represent sites of PCa and this information should be taken into when guiding patient therapy.}, subject = {Positronen-Emissions-Tomografie}, language = {en} } @unpublished{WohlgemuthMiyazakiTsukadaetal.2017, author = {Wohlgemuth, Matthias and Miyazaki, Mitsuhiko and Tsukada, Kohei and Weiler, Martin and Dopfer, Otto and Fujii, Masaaki and Mitrić, Roland}, title = {Deciphering environment effects in peptide bond solvation dynamics by experiment and theory}, series = {Physical Chemistry Chemical Physics}, journal = {Physical Chemistry Chemical Physics}, doi = {10.1039/C7CP03992A}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159483}, year = {2017}, abstract = {Most proteins work in aqueous solution and the interaction with water strongly affects their structure and function. However, experimentally the motion of a specific single water molecule is difficult to trace by conventional methods, because they average over the heterogeneous solvation structure of bulk water surrounding the protein. Here, we provide a detailed atomistic picture of the water rearrangement dynamics around the -CONH- peptide linkage in the two model systems formanilide and acetanilide, which simply differ by the presence of a methyl group at the peptide linkage. The combination of picosecond pump-probe time-resolved infrared spectroscopy and molecular dynamics simulations demonstrates that the solvation dynamics at the molecular level is strongly influenced by this small structural difference. The effective timescales for solvent migration triggered by ionization are mainly controlled by the efficiency of the kinetic energy redistribution rather than the shape of the potential energy surface. This approach provides a fundamental understanding of protein hydration and may help to design functional molecules in solution with tailored properties.}, language = {en} } @unpublished{WohlgemuthMitric2020, author = {Wohlgemuth, Matthias and Mitric, Roland}, title = {Excitation energy transport in DNA modelled by multi-chromophoric field-induced surface hopping}, series = {Physical Chemistry Chemical Physics}, journal = {Physical Chemistry Chemical Physics}, edition = {submitted version}, doi = {10.1039/D0CP02255A}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-209467}, year = {2020}, abstract = {Absorption of ultraviolet light is known as a major source of carcinogenic mutations of DNA. The underlying processes of excitation energy dissipation are yet not fully understood. In this work we provide a new and generally applicable route for studying the excitation energy transport in multi-chromophoric complexes at an atomistic level. The surface-hopping approach in the frame of the extended Frenkel exciton model combined with QM/MM techniques allowed us to simulate the photodynamics of the alternating (dAdT)10 : (dAdT)10 double-stranded DNA. In accordance with recent experiments, we find that the excited state decay is multiexponential, involving a long and a short component which are due to two distinct mechanisms: formation of long-lived delocalized excitonic and charge transfer states vs. ultrafast decaying localized states resembling those of the bare nucleobases. Our simulations explain all stages of the ultrafast photodynamics including initial photoexcitation, dynamical evolution out of the Franck-Condon region, excimer formation and nonradiative relaxation to the ground state.}, language = {en} } @unpublished{WernerIlhanLehneretal.2018, author = {Werner, Rudolf A. and Ilhan, Harun and Lehner, Sebastian and Papp, L{\´a}szl{\´o} and Zs{\´o}t{\´e}r, Norbert and Schatka, Imke and Muegge, Dirk O. and Javadi, Mehrbod S. and Higuchi, Takahiro and Buck, Andreas K. and Bartenstein, Peter and Bengel, Frank and Essler, Markus and Lapa, Constantin and Bundschuh, Ralph A.}, title = {Pre-therapy Somatostatin-Receptor-Based Heterogeneity Predicts Overall Survival in Pancreatic Neuroendocrine Tumor Patients Undergoing Peptide Receptor Radionuclide Therapy}, series = {Molecular Imaging and Biology}, journal = {Molecular Imaging and Biology}, issn = {1536-1632}, doi = {https://doi.org/10.1007/s11307-018-1252-5}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164624}, year = {2018}, abstract = {Purpose: Early identification of aggressive disease could improve decision-support in pancreatic neuroendocrine tumor (pNET) patients prior to peptide receptor radionuclide therapy (PRRT). The prognostic value of intratumoral textural features (TF) determined by baseline somatostatin receptor (SSTR)-PET before PRRT was analyzed. Procedures: 31 patients with G1/G2 pNET were enrolled (G2, n=23/31). Prior to PRRT with [\(^{177}\)Lu]DOTATATE (mean, 3.6 cycles), baseline SSTR-PET/CT was performed. By segmentation of 162 (median per patient, 5) metastases, intratumoral TF were computed. The impact of conventional PET parameters (SUV\(_{mean/max}\)), imaging-based TF as well as clinical parameters (Ki67, CgA) for prediction of both progression-free (PFS) and overall survival (OS) after PRRT was evaluated. Results: Within a median follow-up of 3.7y, tumor progression was detected in 21 patients (median, 1.5y) and 13/31 deceased (median, 1.9y). In ROC analysis, the TF Entropy, reflecting derangement on a voxel-by-voxel level, demonstrated predictive capability for OS (cutoff=6.7, AUC=0.71, p=0.02). Of note, increasing Entropy could predict a longer survival (>6.7, OS=2.5y, 17/31), whereas less voxel-based derangement portended inferior outcome (<6.7, OS=1.9y, 14/31). These findings were supported in a G2 subanalysis (>6.9, OS=2.8y, 9/23 vs. <6.9, OS=1.9y, 14/23). Kaplan-Meier analysis revealed a significant distinction between high- and low-risk groups using Entropy (n=31, p<0.05). For those patients below the ROC-derived threshold, the relative risk of death after PRRT was 2.73 (n=31, p=0.04). Ki67 was negatively associated with PFS (p=0.002); however, SUVmean/max failed in prognostication (n.s.). Conclusions: In contrast to conventional PET parameters, assessment of intratumoral heterogeneity demonstrated superior prognostic performance in pNET patients undergoing PRRT. This novel PET-based strategy of outcome prediction prior to PRRT might be useful for patient risk stratification.}, subject = {Positronen-Emissions-Tomografie}, language = {en} } @unpublished{WernerBundschuhBundschuhetal.2018, author = {Werner, Rudolf A. and Bundschuh, Ralph A. and Bundschuh, Lena and Javadi, Mehrbod S. and Leal, Jeffrey P. and Higuchi, Takahiro and Pienta, Kenneth J. and Buck, Andreas K. and Pomper, Martin G. and Gorin, Michael A. and Lapa, Constantin and Rowe, Steven P.}, title = {Interobserver Agreement for the Standardized Reporting System PSMA-RADS 1.0 on \(^{18}\)F-DCFPyL PET/CT Imaging}, series = {Journal of Nuclear Medicine}, journal = {Journal of Nuclear Medicine}, issn = {0161-5505}, doi = {10.2967/jnumed.118.217588}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-167788}, year = {2018}, abstract = {Objectives: Recently, the standardized reporting and data system for prostate-specific membrane antigen (PSMA)-targeted positron emission tomography (PET) imaging studies, termed PSMA-RADS version 1.0, was introduced. We aimed to determine the interobserver agreement for applying PSMA-RADS to imaging interpretation of 18F-DCFPyL PET examinations in a prospective setting mimicking the typical clinical work-flow at a prostate cancer referral center. Methods: Four readers (two experienced readers (ER, > 3 years of PSMA-targeted PET interpretation experience) and two inexperienced readers (IR, < 1 year of experience)), who had all read the initial publication on PSMA-RADS 1.0, assessed 50 18F-DCFPyL PET/computed tomography (CT) studies independently. Per scan, a maximum of 5 target lesions were selected by the observers and a PSMA-RADS score for every target lesion was recorded. No specific pre-existing conditions were placed on the selection of the target lesions, although PSMA-RADS 1.0 suggests that readers focus on the most highly avid or largest lesions. An overall scan impression based on PSMA-RADS was indicated and interobserver agreement rates on a target lesion-based, on an organ-based, and on an overall PSMA-RADS score-based level were computed. Results: The number of target lesions identified by each observer were as follows: ER 1, 123; ER 2, 134; IR 1, 123; and IR 2, 120. Among those selected target lesions, 125 were chosen by at least two individual observers (all four readers selected the same target lesion in 58/125 (46.4\%) instances, three readers in 40/125 (32\%) and two observers in 27/125 (21.6\%) instances). The interobserver agreement for PSMA-RADS scoring among identical target lesions was good (intraclass correlation coefficient (ICC) for four, three and two identical target lesions, ≥0.60, respectively). For lymph nodes, an excellent interobserver agreement was derived (ICC=0.79). The interobserver agreement for an overall scan impression based on PSMA-RADS was also excellent (ICC=0.84), with a significant difference for ER (ICC=0.97) vs. IR (ICC=0.74, P=0.005). Conclusions: PSMA-RADS demonstrates a high concordance rate in this study, even among readers with different levels of experience. This suggests that PSMA-RADS can be effectively used for communication with clinicians and can be implemented in the collection of data for large prospective trials.}, subject = {Positronen-Emissions-Tomografie}, language = {en} } @unpublished{WernerBundschuhBundschuhetal.2019, author = {Werner, Rudolf A. and Bundschuh, Ralph A. and Bundschuh, Lena and Fanti, Stefano and Javadi, Mehrbod S. and Higuchi, Takahiro and Weich, A. and Pienta, Kenneth J. and Buck, Andreas K. and Pomper, Martin G. and Gorin, Michael A. and Herrmann, Ken and Lapa, Constantin and Rowe, Steven P.}, title = {Novel Structured Reporting Systems for Theranostic Radiotracers}, series = {Journal of Nuclear Medicine}, journal = {Journal of Nuclear Medicine}, issn = {0161-5505}, doi = {10.2967/jnumed.118.223537}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-174629}, year = {2019}, abstract = {Standardized reporting is more and more routinely implemented in clinical practice and such structured reports have a major impact on a large variety of medical fields, e.g. laboratory medicine, pathology, and, recently, radiology. Notably, the field of nuclear medicine is constantly evolving, as novel radiotracers for numerous clinical applications are developed. Thus, framework systems for standardized reporting in this field may a) increase clinical acceptance of new radiotracers, b) allow for inter- and intra-center comparisons for quality assurance, and c) may be used in (global) multi-center studies to ensure comparable results and enable efficient data abstraction. In the last two years, several standardized framework systems for positron emission tomography (PET) radiotracers with potential theranostic applications have been proposed. These include systems for prostate-specific membrane antigen (PSMA)-targeted PET agents for the diagnosis and treatment of prostate cancer (PCa) and somatostatin receptor (SSTR)-targeted PET agents for the diagnosis and treatment of neuroendocrine neoplasias. In the present review, those standardized framework systems for PSMA- and SSTR-targeted PET will be briefly introduced followed by an overview of their advantages and limitations. In addition, potential applications will be defined, approaches to validate such concepts will be proposed, and future perspectives will be discussed.}, subject = {Positronen-Emissions-Tomografie}, language = {en} } @unpublished{WernerAndreeJavadietal.2018, author = {Werner, Rudolf A. and Andree, Christian and Javadi, Mehrbod S. and Lapa, Constantin and Buck, Andreas K. and Higuchi, Takahiro and Pomper, Martin G. and Gorin, Michael A. and Rowe, Steven P. and Pienta, Kenneth J.}, title = {A Voice From the Past: Re-Discovering the Virchow Node with PSMA-targeted \(^{18}\)F-DCFPyL PET Imaging}, series = {Urology - The Gold Journal}, journal = {Urology - The Gold Journal}, issn = {0090-4295}, doi = {10.1016/j.urology.2018.03.030}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-161103}, year = {2018}, abstract = {No abstract available.}, subject = {Virchow Node}, language = {en} } @unpublished{WeithmannKlug2013, author = {Weithmann, Sabrina and Klug, Stefan}, title = {Integrative Sustainable Concepts for Individual Mobility in Asia - A Qualitative Analysis of Carsharing and Taxi Services in Singapore}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-145982}, year = {2013}, abstract = {Singapore has a unique and proactive approach towards managing the national transport system. This article explores the integrative approach of carsharing into the overall transport system from an individual sustainable mobility perspective. The authors argue that for Singapore, taxi services are the strongest competitor for the establishment of free-floating carsharing systems. Low taxi fares and a high distribution rate provide easy access for consumers and show great advantages in correspondence with the prevalent transport measures. Furthermore, the Singaporean government considers taxi services as part of public transport that helps bridging public transportation gaps in door-to-door travel. The article draws on literature review and expert interviews to evaluate the current market conditions and analyse the pros and cons of carsharing systems and taxi services as integrated part of the public transport system. The authors conclude by stating that from a sustainable perspective, the goal is to replace private car ownership. Provision of multi modal choices and therefore co-existence of different individual transport opportunities is indispensable.}, language = {en} } @unpublished{WangArrowsmithBraunschweigetal.2017, author = {Wang, Sunewang Rixin and Arrowsmith, Merle and Braunschweig, Holger and Dewhurst, Rian and Paprocki, Valerie and Winner, Lena}, title = {CuOTf-mediated intramolecular diborene hydroarylation}, series = {Chemical Communications}, journal = {Chemical Communications}, doi = {10.1039/C7CC07371B}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-154055}, year = {2017}, abstract = {Upon complexation to CuOTf, a PMe\(_3\)-stabilized bis(9-anthryl) diborene slowly undergoes an intramolecular hydroarylation reaction at room temperature. Subsequent triflation of the B-H bond with CuOTf, followed by a PMe\(_3\) transfer, finally yields a cyclic sp\(^2\)-sp\(^3\) boryl-substituted boronium triflate salt.}, language = {en} } @unpublished{WangArrowsmithBraunschweigetal.2017, author = {Wang, Sunewang Rixin and Arrowsmith, Merle and Braunschweig, Holger and Dewhurst, Rian and D{\"o}mling, Michael and Mattock, James and Pranckevicius, Conor and Vargas, Alfredo}, title = {Monomeric 16-Electron π-Diborene Complexes of Zn(II) and Cd(II)}, series = {Journal of the American Chemical Society}, journal = {Journal of the American Chemical Society}, doi = {10.1021/jacs.7b06644}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-153058}, year = {2017}, abstract = {Despite the prevalence of stable π-complexes of most d\(^{10}\) metals, such as Cu(I) and Ni(0), with ethylene and other olefins, complexation of d\(^{10}\) Zn(II) to simple olefins is too weak to form isolable complexes due to the metal ion's limited capacity for π-backdonation. By employing more strongly donating π- ligands, namely neutral diborenes with a high-lying π(B=B) or- bital, monomeric 16-electron M(II)-diborene (M = Zn, Cd) π- complexes were synthesized in good yields. Metal-B2 π- interactions in both the solid and solution state were confirmed by single-crystal X-ray analyses and their solution NMR and UV-vis absorption spectroscopy, respectively. The M(II) centers adopt a trigonal planar geometry and interact almost symmetrically with both boron atoms. The MB2 planes significantly twist out of the MX\(_2\) planes about the M-centroid(B-B) vector, with angles rang- ing from 47.0° to 85.5°, depending on the steric interactions be- tween the diborene ligand and the MX\(_2\) fragment.}, language = {en} } @unpublished{WangArrowsmithBoehnkeetal.2017, author = {Wang, Sunewang R. and Arrowsmith, Merle and B{\"o}hnke, Julian and Braunschweig, Holger and Dellermann, Theresa and Dewhurst, Rian D. and Kelch, Hauke and Krummenacher, Ivo and Mattock, James D. and M{\"u}ssig, Jonas H. and Thiess, Torsten and Vargas, Alfredo and Zhang, Jiji}, title = {Engineering a Small HOMO-LUMO Gap and Intramolecular B-B Hydroarylation by Diborene/Anthracene Orbital Intercalation}, series = {Angewandte Chemie, International Edition}, volume = {56}, journal = {Angewandte Chemie, International Edition}, number = {27}, doi = {10.1002/anie.201704063}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148126}, pages = {8009-8013}, year = {2017}, abstract = {The diborene 1 was synthesized by reduction of a mixture of 1,2-di-9-anthryl-1,2-dibromodiborane(4) (6) and trimethylphosphine with potassium graphite. The X-ray structure of 1 shows the two anthryl rings to be parallel and their π(C\(_{14}\)) systems perpendicular to the diborene π(B=B) system. This twisted conformation allows for intercalation of the relatively high-lying π(B=B) orbital and the low-lying π* orbital of the anthryl moiety with no significant conjugation, resulting in a small HOMO-LUMO gap (HLG) and ultimately an unprecedented anthryl B-B bond hydroarylation. The HLG of 1 was estimated to be 1.57 eV from the onset of the long wavelength band in its UV-vis absorption spectrum (THF, λ\(_{onset}\) = 788 nm). The oxidation of 1 with elemental selenium afforded diboraselenirane 8 in quantitative yield. By oxidative abstraction of one phosphine ligand by another equivalent of elemental selenium, the B-B and C\(^1\)-H bonds of 8 were cleaved to give the cyclic 1,9-diboraanthracene 9.}, language = {en} } @unpublished{TitovHumeniukMitric2020, author = {Titov, Evgenii and Humeniuk, Alexander and Mitric, Roland}, title = {Comparison of moving and fixed basis sets for nonadiabatic quantum dynamics at conical intersections}, series = {Chemical Physics}, journal = {Chemical Physics}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-199225}, year = {2020}, abstract = {We assess the performance of two different types of basis sets for nonadiabatic quantum dynamics at conical intersections. The basis sets of both types are generated using Ehrenfest trajectories of nuclear coherent states. These trajectories can either serve as a moving (time-dependent) basis or be employed to sample a fixed (time-independent) basis. We demonstrate on the example of two-state two-dimensional and three-state five-dimensional models that both basis set types can yield highly accurate results for population transfer at intersections, as compared with reference quantum dynamics. The details of wave packet evolutions are discussed for the case of the two-dimensional model. The fixed basis is found to be superior to the moving one in reproducing nonlocal spreading and maintaining correct shape of the wave packet upon time evolution. Moreover, for the models considered, the fixed basis set outperforms the moving one in terms of computational efficiency.}, language = {en} } @unpublished{TitovHumeniukMitric2018, author = {Titov, Evgenii and Humeniuk, Alexander and Mitric, Roland}, title = {Exciton localization in excited-state dynamics of a tetracene trimer: A surface hopping LC-TDDFTB study}, series = {Physical Chemistry Chemical Physics}, journal = {Physical Chemistry Chemical Physics}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-198680}, year = {2018}, abstract = {Excitons in the molecular aggregates of chromophores are key participants in important processes such as photosynthesis or the functioning of organic photovoltaic devices. Therefore, the exploration of exciton dynamics is crucial. Here we report on exciton localization during excited-state dynamics of the recently synthesized tetracene trimer [Liu et al., Org. Lett., 2017, 19, 580]. We employ the surface hopping approach to nonadiabatic molecular dynamics in conjunction with the long-range corrected time-dependent density functional tight binding (LC-TDDFTB) method [Humeniuk and Mitrić, Comput. Phys. Commun., 2017, 221, 174]. Utilizing a set of descriptors based on the transition density matrix, we perform comprehensive analysis of exciton dynamics. The obtained results reveal an ultrafast exciton localization to a single tetracene unit of the trimer during excited-state dynamics, along with exciton transfer between units.}, language = {en} } @unpublished{TitovHumeniukMitric2020, author = {Titov, Evgenii and Humeniuk, Alexander and Mitric, Roland}, title = {Comparison of moving and fixed basis sets for nonadiabatic quantum dynamics at conical intersections}, series = {Chemical Physics}, journal = {Chemical Physics}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-198699}, year = {2020}, abstract = {We assess the performance of two different types of basis sets for nonadiabatic quantum dynamics at conical intersections. The basis sets of both types are generated using Ehrenfest trajectories of nuclear coherent states. These trajectories can either serve as a moving (time-dependent) basis or be employed to sample a fixed (time-independent) basis. We demonstrate on the example of two-state two-dimensional and three-state five-dimensional models that both basis set types can yield highly accurate results for population transfer at intersections, as compared with reference quantum dynamics. The details of wave packet evolutions are discussed for the case of the two-dimensional model. The fixed basis is found to be superior to the moving one in reproducing true nonlocal spreading and maintaining correct shape of the wave packet upon time evolution. Moreover, for the models considered, the fixed basis set outperforms the moving one in terms of computational efficiency.}, language = {en} } @unpublished{SuessWehnerDostaletal.2019, author = {S{\"u}ß, Jasmin and Wehner, Johannes G. and Dost{\´a}l, Jakub and Engel, Volker and Brixner, Tobias}, title = {Mapping of exciton-exciton annihilation in a molecular dimer via fifth-order femtosecond two-dimensional spectroscopy}, series = {Journal of Physical Chemistry Letters}, journal = {Journal of Physical Chemistry Letters}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178482}, year = {2019}, abstract = {We present a theoretical study on exciton-exciton annihilation (EEA) in a molecular dimer. This process is monitored using a fifth-order coherent two-dimensional (2D) spectroscopy as was recently proposed by Dost{\´a}l et al. [Nat. Commun. 9, 2466 (2018)]. Using an electronic three-level system for each monomer, we analyze the different paths which contribute to the 2D spectrum. The spectrum is determined by two entangled relaxation processes, namely, the EEA and the direct relaxation of higher lying excited states. It is shown that the change of the spectrum as a function of a pulse delay can be linked directly to the presence of the EEA process.}, subject = {Exziton}, language = {en} } @unpublished{StoyBoehnkeJiménezHallaetal.2018, author = {Stoy, Andreas and B{\"o}hnke, Julian and Jiménez-Halla, J. Oscar C. and Dewhurst, Rian D. and Thiess, Torsten and Braunschweig, Holger}, title = {CO\(_2\) Binding and Splitting by Boron-Boron Multiple Bonds}, series = {Angewandte Chemie, International Edition}, journal = {Angewandte Chemie, International Edition}, doi = {10.1002/anie.201802117}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164265}, year = {2018}, abstract = {CO\(_2\) is found to undergo room-temperature, ambient- pressure reactions with two species containing boron-boron multiple bonds, leading to incorporation of either one or two CO\(_2\) molecules. In one case, a thermally-unstable intermediate was structurally characterized, indicating the operation of an initial 2+2 cycloaddition mechanism in the reaction.}, language = {en} } @unpublished{StennettMattockVollertetal.2018, author = {Stennett, Tom and Mattock, James and Vollert, Ivonne and Vargas, Alfredo and Braunschweig, Holger}, title = {Unsymmetrical, Cyclic Diborenes and Thermal Rearrangement to a Borylborylene}, series = {Angewandte Chemie, International Edition}, volume = {57}, journal = {Angewandte Chemie, International Edition}, doi = {10.1002/anie.201800671}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-160258}, pages = {4098-4102}, year = {2018}, abstract = {Cyclic diboranes(4) based on a chelating monoanionic, benzylphosphine linker were prepared by boron-silicon exchange between arylsilanes and B\(_2\)Br\(_4\). Coordination of Lewis bases to the remaining sp\(^2\) boron atom yielded unsymmetrical sp\(^3\)-sp\(^3\) diboranes, which were reduced with KC\(_8\) to their corresponding trans-diborenes. These compounds were studied by a combination of spectroscopic methods, X-ray diffraction and DFT calculations. PMe\(_3\)-stabilized diborene 6 was found to undergo thermal rearrangement to gem- diborene 8. DFT calculations on 8 reveal a polar boron-boron bond, and indicate that the compound is best described as a borylborylene.}, language = {en} } @unpublished{StennettMattockPentecostetal.2018, author = {Stennett, Tom and Mattock, James and Pentecost, Leanne and Vargas, Alfredo and Braunschweig, Holger}, title = {Chelated Diborenes and their Inverse-Electron-Demand Diels- Alder Reactions with Dienes}, series = {Angewandte Chemie, International Edition}, journal = {Angewandte Chemie, International Edition}, doi = {10.1002/anie.201809217}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178268}, year = {2018}, abstract = {A doubly base-stabilized diborane based on a benzylphosphine linker was prepared by a salt elimination reaction between 2-LiC\(_6\)H\(_4\)CH\(_2\)PCy\(_2\).Et\(_2\)O and B\(_2\)Br\(_4\). This compound was reduced with KC8 to its corresponding diborene, with the benzylphosphine forming a five-membered chelate. The diborene reacts with butadiene, 2-trimethylsiloxy-1,3-butadiene and isoprene to form 4,5-diboracyclohexenes, which interconvert between their 1,1- (geminal) and 1,2- (vicinal) chelated isomers. The 1,1-chelated diborene undergoes a halide-catalysed isomerisation into its thermodynamically favoured 1,2-isomer, which undergoes Diels-Alder reactions more slowly than the kinetic product.}, language = {en} } @unpublished{StennettBissingerGriesbecketal.2019, author = {Stennett, Tom E. and Bissinger, Philipp and Griesbeck, Stefanie and Ullrich, Stefan and Krummenacher, Ivo and Auth, Michael and Sperlich, Andreas and Stolte, Matthias and Radacki, Krzysztof and Yao, Chang-Jiang and W{\"u}rthner, Frank and Steffen, Andreas and Marder, Todd B. and Braunschweig, Holger}, title = {Near-Infrared Quadrupolar Chromophores Combining Three-Coordinate Boron-Based Superdonor and Superacceptor Units}, series = {Angewandte Chemie, International Edition}, journal = {Angewandte Chemie, International Edition}, doi = {10.1002/anie.201900889}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-180391}, year = {2019}, abstract = {In this work, two new quadrupolar A-π-D-π-A chromophores have been prepared featuring a strongly electron- donating diborene core and strongly electron-accepting dimesitylboryl F(BMes2) and bis(2,4,6-tris(trifluoromethyl)phenyl)boryl (BMes2) end groups. Analysis of the compounds by NMR spectroscopy, X-ray crystallography, cyclic voltammetry and UV-vis-NIR absorption and emission spectroscopy indicated that the compounds possess extended conjugated π-systems spanning their B4C8 cores. The combination of exceptionally potent π-donor (diborene) and π- acceptor (diarylboryl) groups, both based on trigonal boron, leads to very small HOMO-LUMO gaps, resulting in strong absorption in the near-IR region with maxima in THF at 840 and 1092 nm, respectively, and very high extinction coefficients of ca. 120,000 M-1cm-1. Both molecules also display weak near-IR fluorescence with small Stokes shifts.}, language = {en} } @unpublished{StennettBertermannBraunschweig2018, author = {Stennett, Tom and Bertermann, R{\"u}diger and Braunschweig, Holger}, title = {Construction of Linear and Branched Tetraboranes via 1,1- and 1,2-Diboration of Diborenes}, series = {Angewandte Chemie, International Edition}, journal = {Angewandte Chemie, International Edition}, doi = {10.1002/anie.201809976}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178276}, year = {2018}, abstract = {Sterically unencumbered diborenes based on a benzylphosphine chelate undergo diboration reactions with bis(catecholato)diboron in the absence of a catalyst to yield tetraboranes. The symmetrical diborenes studied undergo 1,2- diborations, whereas an unsymmetrical derivative was found to yield a triborylborane-phosphine adduct as the result of a formal 1,1-diboration. A related borylborylene compound also underwent a 1,2-diboration to produce a borylene-borane adduct.}, language = {en} }