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91.
Anomalous structure-luminescence relationship in phosphorescent gold(I) isonitrile neutral complexes
Elbjeirami O Omary MA Stender M Balch AL 《Dalton transactions (Cambridge, England : 2003)》2004,(20):3173-3175
A new compound that exhibits the shortest intermolecular Au...Au distance ever reported for neutral RNCAuX complexes is found to exhibit a counterintuitive higher-energy Au-centered phosphorescence than that in an analogous compound with a much longer Au...Au distance, presumably due to a different extent of excited-state distortion in dimers vs. extended chains. 相似文献
92.
Köster S Angilè FE Duan H Agresti JJ Wintner A Schmitz C Rowat AC Merten CA Pisignano D Griffiths AD Weitz DA 《Lab on a chip》2008,8(7):1110-1115
We use microfluidic devices to encapsulate, incubate, and manipulate individual cells in picoliter aqueous drops in a carrier fluid at rates of up to several hundred Hz. We use a modular approach with individual devices for each function, thereby significantly increasing the robustness of our system and making it highly flexible and adaptable to a variety of cell-based assays. The small volumes of the drops enables the concentrations of secreted molecules to rapidly attain detectable levels. We show that single hybridoma cells in 33 pL drops secrete detectable concentrations of antibodies in only 6 h and remain fully viable. These devices hold the promise of developing microfluidic cell cytometers and cell sorters with much greater functionality, allowing assays to be performed on individual cells in their own microenvironment prior to analysis and sorting. 相似文献
93.
Dr. Tino P. Golub Malte Feßner Dr. Elric Engelage Prof. Dr. Christian Merten 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(45):e202201317
In this study, we characterize the dynamic stereochemistry of a biphenyl-2,2’-bis(proline amide) catalyst in chloroform and DMSO as representative weakly and strongly hydrogen bonding solvents. Using vibrational circular dichroism (VCD) spectroscopy and density functional theory (DFT) based spectra calculations, we show that the preferred axial stereochemistry of the catalyst is determined by solute-solvent interactions. Explicitly considering solvation with DMSO molecules is found to be essential to correctly predict the conformational preferences of the catalyst. Furthermore, we investigate the stereochemistry of the corresponding enamines and imidazolidinones that are formed upon reaction with isovaleraldehyde. The enamines are found to rapidly convert to endo-imidazolidinones and the thermodynamically favored exo-imidazolidinones are formed only slowly. The present study demonstrates that the stereochemistry of these imidazolidinones can be deduced directly from the VCD spectra analysis without any further detailed analysis of NMR spectra. Hence, we herein exemplify the use of VCD spectroscopy for an in situ characterization of intermediates relevant in asymmetric catalysts. 相似文献
94.
Christopher L. Stender Perumal Sekar Teri W. Odom 《Journal of solid state chemistry》2008,181(7):1621-1627
This article focuses on two different approaches to create nanoscale transition metal chalcogenide materials. First, we used chemical nanofabrication, a combination of top-down patterning and bottom-up solid-state synthesis, to achieve control over the shape, size, and ordering of the patterned nanomaterials. We demonstrated orientational control over nanocrystals within sub-300 nm patterns of MoS2 and formed free-standing nanostructures of crystalline NiS2. In addition, crossed line arrays of mixed metal chalcogenide nanostructures were achieved, and TaS2 nanopatterns were made by the chemical transformation of tantalum oxide templates. Second, we developed a one-pot procedure using molecular precursors to synthesize two-dimensional NbSe2, TaS2 and TaSe2 nanoplates and one-dimensional NbSe2 wires depending on the relative amount of surfactants in the reaction mixture. Prospects for these transition metal chalcogenide nanomaterials with controlled shapes and morphologies will be discussed. 相似文献
95.
Daniel Sowa Prendes Florian Papp Nagesh Sankaran Nardana Sivendran Frederike Beyer Christian Merten Prof. Dr. Lukas J. Gooßen 《Angewandte Chemie (International ed. in English)》2023,62(49):e202309868
Arylglycines are important pharmacophores present in several top-selling drugs. This compound class has now been made accessible from abundant aryl chlorides by a Pd-catalyzed Schöllkopf-type amino acid synthesis. In the presence of the catalyst methylnaphthyl(XPhos)-palladium bromide, the base lithium 2,2,6,6-tetramethylpyrrolidide and the additive ZnCl2, tert-leucine-derived bis-lactim ethers were efficiently arylated at room temperature, reaching yields of 95 % and diastereoselectivities of 98 : 2. Hydrolysis gave the corresponding arylglycines in high enantiomeric excess. 相似文献
96.
97.
Dirk Merten Ralf Ricken Matthias Koll Bernard Metsch Herbert Petry 《Czechoslovak Journal of Physics》2001,51(2):B152-B159
In this contribution, the results on the spectra and semileptonic decays of light and heavy mesons in a relativistic constituent quark model incorporating a confinement potential as well as a residual interaction induced by instantons are reported. 相似文献
98.
99.
Dr. Merten Grupe Pit Boden Patrick Di Martino-Fumo Dr. Xin Gui Cecilia Bruschi Roumany Israil Marcel Schmitt Dr. Martin Nieger Prof. Dr. Markus Gerhards Prof. Dr. Wim Klopper Dr. Christoph Riehn Dr. Claudia Bizzarri Prof. Dr. Rolf Diller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(61):15252-15271
Chemical and spectroscopic characterization of the mononuclear photosensitizers [(DPEPhos)Cu(I)(MPyrT)]0/+ ( CuL , CuLH ) and their dinuclear analogues ( Cu2L’ , Cu2L'H2 ), backed by (TD)DFT and high-level GW-Bethe-Salpeter equation calculations, exemplifies the complex influence of charge, nuclearity and structural flexibility on UV-induced photophysical pathways. Ultrafast transient absorption and step-scan FTIR spectroscopy reveal flattening distortion in the triplet state of CuLH as controlled by charge, which also appears to have a large impact on the symmetry of the long-lived triplet states in Cu2L’ and Cu2L'H2 . Time-resolved luminescence spectroscopy (solid state), supported by transient photodissociation spectroscopy (gas phase), confirm a lifetime of some tens of μs for the respective triplet states, as well as the energetics of thermally activated delayed luminescence, both being essential parameters for application of these materials based on earth-abundant copper in photocatalysis and luminescent devices. 相似文献
100.
Dr. Damian Pleschka Marten Uebing Dr. Merten Lange Dr. Alexander Hepp Anna-Lena Wübker Prof. Dr. Michael Ryan Hansen Prof. Dr. Ernst-Ulrich Würthwein Prof. Dr. Werner Uhl 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(39):9315-9325
Al/P- and Ga/P-based frustrated Lewis pairs (FLPs) reacted with an azirine under mild conditions under cleavage of the heterocycle on two different positions. Opening of the C−C bond yielded an unusual nitrile–ylide adduct in which a C−N moiety coordinated to the FLP backbone. Cleavage of a C−N bond afforded the thermodynamically favored enamine adduct with the N atom bound to P and Al or Ga atoms. Ring closure was observed upon treatment of an Al/P FLP with electronically unsaturated substrates (4-(1-cyclohexenyl)-1-aza-but-1-en-3-ynes) and yielded by C−N bond formation hexahydroquinoline derivatives, which coordinated to the FLP through P−C and Al−C bonds. Diphenylcyclopropenone showed a diverse reactivity, which depending on steric shielding and the polarizing effect of Al or Ga atoms afforded different products. An AltBu2/P FLP yielded an adduct with the C=O group coordinated to P and Al. The dineopentyl derivative gave an equilibrium mixture consisting of a similar product and a simple adduct with O bound to Al and a three-coordinate P atom. Both compounds co-crystallize. The Ga/P FLP only formed the simple adduct with the same substrate. Rearrangement resulted in all cases in C3-ring cleavage and migration of a mesityl group from P to a former ring C atom by C−C bond formation. Diphenylthiocyclopropenone (evidence for the presence of P=C bonds) and an imine derivative afforded similar products. 相似文献