@phdthesis{Krebs2023, author = {Krebs, Johannes Heinrich}, title = {Investigation of Dicarba-closo-dodecaborane as a Substituent on Three-coordinate Boron and as an Acceptor in a Pyrene-Donor-Acceptor System}, doi = {10.25972/OPUS-28675}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-286758}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2023}, abstract = {1. Bis(1-(4-tolyl)-carboran-2-yl)-(4-tolyl)-borane, a new bis(o-carboranyl)-(R)-borane 1 was synthesised by lithiation of the o-carboranyl precursor and subsequent salt metathesis reaction with (4-tolyl)BBr2. Cyclic voltammetry experiments on 1 show multiple distinct reduction events with a one-electron first reduction. In a selective reduction experiment the corresponding paramagnetic radical anion 1•- was isolated and characterized. Single-crystal structure analyses allow an in-depth comparison of 1, 1•-, their calculated geometries, and the S1 excited state of 1. 2. The choice of backbone linker for ortho-bis-(9-borafluorene)s has a great influence on the LUMO located at the boron centers and therefore the reactivity of the respective compounds. Herein, we report the room temperature rearrangement of 1,2-bis-(9-borafluorenyl-)-ortho-carborane, C2B10H10-1,2-[B(C12H8)]2 ([2a]) featuring o-carborane as the inorganic three-dimensional backbone and the synthesis of 1,2-bis-(9-borafluorenyl-)benzene, C6H4-1,2-[B(C12H8)]2 (2b) its phenylene analog. DFT calculations on the transition state for the rearrangement support an intramolecular C-H bond activation process via an SEAr-like mechanism in [2a], and predicted that the same rearrangement would take place in 2b, but at elevated temperatures, which indeed proved to be the case. 3. We synthesized 4 a julolidine-like pyrenyl-o-carborane, with pyrene substituted at the 2,7-positions on the HOMO/LUMO nodal plane, continuing our research. Using solid state molecular structures, photophysical data, cyclic voltammetry, DFT and TD-DFT calculations we compare o-carborane and the B(mes)2 (mes = 2,4,6-Me3C6H2) as acceptor groups and confirm the julolidine-like donor strength.}, subject = {closo-Borane}, language = {en} } @article{KotlyarKrebsSolimandoetal.2023, author = {Kotlyar, Mischa J. and Krebs, Markus and Solimando, Antonio Giovanni and Marquardt, Andr{\´e} and Burger, Maximilian and K{\"u}bler, Hubert and Bargou, Ralf and Kneitz, Susanne and Otto, Wolfgang and Breyer, Johannes and Vergho, Daniel C. and Kneitz, Burkhard and Kalogirou, Charis}, title = {Critical evaluation of a microRNA-based risk classifier predicting cancer-specific survival in renal cell carcinoma with tumor thrombus of the inferior vena cava}, series = {Cancers}, volume = {15}, journal = {Cancers}, number = {7}, issn = {2072-6694}, doi = {10.3390/cancers15071981}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-311040}, year = {2023}, abstract = {(1) Background: Clear cell renal cell carcinoma extending into the inferior vena cava (ccRCC\(^{IVC}\)) represents a clinical high-risk setting. However, there is substantial heterogeneity within this patient subgroup regarding survival outcomes. Previously, members of our group developed a microRNA(miR)-based risk classifier — containing miR-21-5p, miR-126-3p and miR-221-3p expression — which significantly predicted the cancer-specific survival (CSS) of ccRCC\(^{IVC}\) patients. (2) Methods: Examining a single-center cohort of tumor tissue from n = 56 patients with ccRCC\(^{IVC}\), we measured the expression levels of miR-21, miR-126, and miR-221 using qRT-PCR. The prognostic impact of clinicopathological parameters and miR expression were investigated via single-variable and multivariable Cox regression. Referring to the previously established risk classifier, we performed Kaplan-Meier analyses for single miR expression levels and the combined risk classifier. Cut-off values and weights within the risk classifier were taken from the previous study. (3) Results: miR-21 and miR-126 expression were significantly associated with lymphonodal status at the time of surgery, the development of metastasis during follow-up, and cancer-related death. In Kaplan-Meier analyses, miR-21 and miR-126 significantly impacted CSS in our cohort. Moreover, applying the miR-based risk classifier significantly stratified ccRCC\(^{IVC}\) according to CSS. (4) Conclusions: In our retrospective analysis, we successfully validated the miR-based risk classifier within an independent ccRCC\(^{IVC}\) cohort.}, language = {en} }