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Bastian Rsch Thomas Xaver Gentner Holger Elsen Christian A. Fischer Jens Langer Michael Wiesinger Sjoerd Harder 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(16):5450-5455
Key to the isolation of the first alkyl strontium complex was the synthesis of a strontium hydride complex that is stable towards ligand exchange reactions. This goal was achieved by using the super bulky β‐diketiminate ligand DIPePBDI (CH[C(Me)N‐DIPeP]2, DIPeP=2,6‐diisopentylphenyl). Reaction of DIPePBDI‐H with Sr[N(SiMe3)2]2 gave (DIPePBDI)SrN(SiMe3)2, which was converted with PhSiH3 into [(DIPePBDI)SrH]2. Dissolved in C6D6, the strontium hydride complex is stable up to 70 °C. At 60 °C, H–D isotope exchange gave full conversion into [(DIPePBDI)SrD]2 and C6D5H. Since H–D exchange with D2 is facile, the strontium hydride complex served as a catalyst for the deuteration of C6H6 by D2. Reaction of [(DIPePBDI)SrH]2 with ethylene gave [(DIPePBDI)SrEt]2. The high reactivity of this alkyl strontium complex is demonstrated by facile ethylene polymerization and nucleophilic aromatic substitution with C6D6, giving alkylated aromatic products and [(DIPePBDI)SrD]2. 相似文献
3.
Lena Quambusch Ina Landel Laura Depta Jrn Weisner Niklas Uhlenbrock Matthias P. Müller Franziska Glanemann Kristina Althoff Jens T. Siveke Daniel Rauh 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(52):18999-19005
Isoforms of protein kinase Akt are involved in essential processes including cell proliferation, survival, and metabolism. However, their individual roles in health and disease have not been thoroughly evaluated. Thus, there is an urgent need for perturbation studies, preferably mediated by highly selective bioactive small molecules. Herein, we present a structure‐guided approach for the design of structurally diverse and pharmacologically beneficial covalent‐allosteric modifiers, which enabled an investigation of the isoform‐specific preferences and the important residues within the allosteric site of the different isoforms. The biochemical, cellular, and structural evaluations revealed interactions responsible for the selective binding profiles. The isoform‐selective covalent‐allosteric Akt inhibitors that emerged from this approach showed a conclusive structure–activity relationship and broke ground in the development of selective probes to delineate the isoform‐specific functions of Akt kinases. 相似文献
4.
The Ramanujan Journal - In this paper we explore special values of Gaussian hypergeometric functions in terms of products of Euler $$\Gamma $$ -functions and exponential functions of linear... 相似文献
5.
Jonas H. Muessig Melanie Thaler Rian D. Dewhurst Valerie Paprocki Jens Seufert James D. Mattock Alfredo Vargas Holger Braunschweig 《Angewandte Chemie (International ed. in English)》2019,58(13):4405-4409
The lability of B=B, B?P, and B–halide bonds is combined in the syntheses of the first diiododiborenes. In a series of reactivity tests, these diiododiborenes undergo cleavage of all six of their central bonds in different ways, leading to products of B=B hydrogenation and dihalogenation as well as halide exchange. 相似文献
6.
Dr. Oliver Hegen Jens Braese Prof. Dr. Alexey Y. Timoshkin Prof. Dr. Manfred Scheer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(2):485-489
A new class of neutral bidentate ligands with pnictogenyl-functional sites has been obtained. The reaction of tmeda⋅(BH2I)2 ( 1 , tmeda=tetramethylethylendiamine) with different phosphanides yields the corresponding bidentate phosphanylboranes tmeda⋅(BH2PH2)2 ( 2 a ), tmeda⋅(BH2PPh2)2 ( 2 b ), and tmeda⋅(BH2tBuPH)2 ( 2 c ). This reaction strategy could be further extended to synthesize the first bidentate arsanylborane tmeda⋅(BH2AsPh2)2 ( 3 ). Depending on the substituents on the phosphorus, these compounds form different AuI complexes, to build either polymeric tmeda⋅(BH2PH2AuCl)2 ( 4 a ), or monomeric tmeda⋅(BH2PPh2AuCl)2 ( 4 b ) products. These compounds form also neutral oligomeric group 13/15 chain-like molecules by coordination to a boron moiety such as tmeda⋅(BH2PH2BH3)2 ( 5 a ) and tmeda⋅(BH2AsPh2BH3)2 ( 5 b ). DFT calculations provide insight into the differences between the syntheses of mono- and bidentate pnictogenylboranes. 相似文献
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Miriam Kohagen Frank Uhlig Jens Smiatek 《International journal of quantum chemistry》2019,119(14):e25933
Recent experimental results indicate that the stability of non-Watson-Crick DNA i-motif structures can be influenced by the presence of various metal cations. Whereas Au+, Cu+, and Ag+ are stabilizing agents, alkali metal ions like Na+ or Li+ are known to destabilize the i-motif. In terms of reduced ion-cytosine complexes, we rationalize the experimental observations with the help of standard and conceptual density functional theory (DFT) calculations. Our results highlight the importance of coordinating electrostatic bonds with partially covalent character for the stability of the ion-cytosine complex. The occurrence of these bonds can be mainly attributed to charge transfer processes between two cytosines and the transition metal ions, which can be either explained by frontier molecular orbital theory in combination with a bond critical point analysis, or by the concept of chemical reactivity indices within a conceptual DFT approach. The results of our calculations establish a consistent theoretical framework to understand the experimentally observed behavior, and are also important in order to achieve more detailed insights into nucleobase pairing mechanisms in general. 相似文献
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Substituted Tetraaza‐ and Hexaazahexacenes and their N,N′‐Dihydro Derivatives: Syntheses,Properties, and Structures 下载免费PDF全文
Jens U. Engelhart Dr. Benjamin D. Lindner Manuel Schaffroth David Schrempp Olena Tverskoy Prof. Uwe H. F. Bunz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8121-8129
The palladium‐catalyzed coupling of a substituted o‐diaminoanthracene and a substituted o‐diaminophenazine to substituted 2,3‐dichloroquinoxalines furnishes 10 differently substituted N,N′‐dihydrotetraaza‐ or ‐hexaazahexacenes with the quinoxaline group of the azaacenes carrying fluorine, chlorine, or nitro groups. The N,N′‐dihydrotetraazahexacenes with hydrogen, chlorine, and fluorine subtituents are oxidized to azaacenes, whereas only the parent N,N′‐dihydrohexaazahexacenes, with hydrogen substituents, are oxidized by MnO2. The resultant azaacenes are characterized by their optical and spectroscopic data. In addition, single‐crystal X‐ray structures have been obtained for the parent tetraazahexacenes and their difluoro‐substituted derivatives. The di‐ and tetrachloro derivatives of the N,N′‐dihydrohexaazahexacene have also been structurally characterized. 相似文献