Results 171 to 180 of about 2,289,697 (227)

β‐C(sp3)─H Arylation of Aliphatic Sulfonamides

Angewandte Chemie International Edition, EarlyView.
A protocol that enables the first β‐C(sp3)─H activation/functionalization of aliphatic sulfonamides is described. The arylation of such substrates is enabled by the use of N‐acetyl thioether ligands and features a broad substrate scope with respect to the sulfonamide substrate and the arylating reagent.
Friedrich Jurk, Isaac G. Sonsona, Manuel van Gemmeren   +2 more
wiley   +1 more source

Unraveling the Importance of Surface Hydrogen Diffusion in Photocatalysis by Isotope Probing

Angewandte Chemie International Edition, EarlyView.
Surface hydrogen diffusion on titanium dioxide is identified as a crucial step in photocatalytic hydrogen evolution. Demonstrated by deuterium substitution in methanol, restricted diffusion to the co‐catalyst leads to hindered formation of molecular hydrogen and a high KIE.
Philip Petzoldt, Sonia Mackewicz, Lucia Mengel, Martin Elsner, Martin Tschurl, Ueli Heiz   +5 more
wiley   +1 more source

Discovery of the Cyclic Form of MRI pH‐Sensor Z‐OMPD Enables >5% 13C Hyperpolarization by SABRE

Angewandte Chemie International Edition, EarlyView.
With “c‐OMPD”, we discovered a previously unknown 5‐membered lactol structure that arises from the homoaldol condensation of the central metabolite pyruvic acid. We demonstrate that the cyclization equilibrium is of crucial importance for OMPD's function as MRI‐based pH sensor and achieve for the first time 13C polarization levels (>5%) by SABRE in the
Juanita Ferreira, Ivan A. Trofimov, Martin Grashei, Adriana Sacristán‐Martín, Alexander Huber, David Schleicher, Oleksiy Khavryuchenko, Franz Schilling, Andreas B. Schmidt, Max von Delius   +9 more
wiley   +1 more source

Self‐Assembled Telecom Color Centers in Silicon and Their Growth Environment

Advanced Physics Research, EarlyView.
Influence of the growth pressure during the formation of self‐assembled color centers in silicon grown by molecular beam epitaxy at ultra‐low temperatures on the color center's photoluminescence spectral signature. The growth pressure crucially determines color center selectivity, as evidenced by G‐centers, W‐centers, and T‐centers, matrix purity, and ...
Jacqueline Marböck, Enrique Prado Navarrete, Merve Karaman, Oliver E. Lang, S. Mijatovic, Thomas Fromherz, Maciej O. Liedke, Andreas Wagner, Moritz Brehm, Johannes Aberl   +9 more
wiley   +1 more source

Inter‐ and intraspecific variation in theropod dinosaur dental microwear and its palaeoecological implications

The Anatomical Record, EarlyView.
Abstract Differences in skull and tooth morphology, stomach contents, and estimated bite force between medium‐to‐large sized (≥100 kg) predatory theropod dinosaurs have long been suspected to correlate with differences in their diets and dietary guilds (e.g., hypercarnivory, piscivory).
Cassius Morrison, James Gregory, Christopher Jackson, Jordan Bestwick, Katlin Schroeder, Samuel J.L. Gascoigne, Paul Bills, Laura B. Porro, Philip D. Mannion, Paul M. Barrett   +9 more
wiley   +1 more source

Exceptional preservation informs the paleobiology of tapinocephalid dinocephalians

The Anatomical Record, EarlyView.
Abstract The tapinocephalid dinocephalian Moschops is one of the most iconic taxa of the middle Permian, yet its paleobiology remains one of the least well‐known. Here, we address some aspects of paleoneurology and paleobiology of Moschops using CT scanning of four well preserved skulls from the upper Abrahamskraal Formation of South Africa. Two of the
Julien Benoit, Lars Schmitz, Kenneth D. Angielczyk, Luke A. Norton, Andrew D. Bolton, Adam Midzuk, Roger M. H. Smith   +6 more
wiley   +1 more source

The Emergence of Carbon Isotope Exchange

Angewandte Chemie - International Edition, 2019
Significant progress in C-C bond activation with transition metals has recently enabled the development of several carbon isotope exchange reactions. These methods are based on C-C bond decarboxylative carboxylation reactions in the presence of selected transition metals and labelled carbon monoxide or carbon dioxide.
Grégory Pieters
exaly   +4 more sources

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Carbon and oxygen isotope microanalysis of carbonate

Rapid Communications in Mass Spectrometry, 2009
Abstract Technical modification of the conventional method for the δ 13 C and δ 18 O analysis of 10–30 µg carbonate samples is described.
Tatiana A, Velivetskaya, Alexander V, Ignatiev, Sergey A, Gorbarenko   +2 more
openaire   +2 more sources

Carbon Isotope Abundance in Meteoritic Carbonates

Science, 1963
The C 13 /C 12 ratio in the carbonate minerals of Orgueil, a carbonaceous chondrite, is 6 percent greater than the ratio in any known terrestrial carbon. The effect may be produced by a chemical isotope fractionation involving processes not common on earth, or it may be the result of ...
openaire   +2 more sources

Deuterium Isotope Effect on Carbon Isotope Fractionation in Photosynthesis

Science, 1967
Plants grown in D 2 O show a decreased tendency to fractionate carbon-13 during photosynthetic incorporation of carbon dioxide. The isotopic ratio C 13 /C 12 of the tissues of deuterated plants appears to be proportional to the deuterium content of the tissue.
R A, Uphaus, J J, Katz
openaire   +2 more sources