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151.
Iodice M Cusanno F Acha A Ambrozewicz P Aniol KA Baturin P Bertin PY Benaoum H Blomqvist KI Boeglin WU Breuer H Brindza P Bydzovský P Camsonne A Chang CC Chen JP Choi S Chudakov EA Cisbani E Colilli S Coman L Craver BJ De Cataldo G de Jager CW De Leo R Deur AP Ferdi C Feuerbach RJ Folts E Fratoni R Frullani S Garibaldi F Gayou O Giulani F Gomez J Gricia M Hansen JO Hayes D Higinbotham DW Holmstrom TK Hyde CE Ibrahim HF Jiang X Kaufman LJ Kino K Kross B Lagamba L LeRose JJ Lindgren RA 《Physical review letters》2007,99(5):052501
An experiment measuring electroproduction of hypernuclei has been performed in hall A at Jefferson Lab on a 12C target. In order to increase counting rates and provide unambiguous kaon identification two superconducting septum magnets and a ring imaging Cherenkov detector were added to the hall A standard equipment. An unprecedented energy resolution of less than 700 keV FWHM has been achieved. Thus, the observed (Lambda)(12)B spectrum shows for the first time identifiable strength in the core-excited region between the ground-state s-wave Lambda peak and the 11 MeV p-wave Lambda peak. 相似文献
152.
Dennis Oprych Prof. Dr. Bernd Strehmel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(13):4297-4301
NIR and UV exposure of systems comprising upconversion nanoparticles ( UCNP ) based on NaYF4:Tm/Yb@NaYF4, a sensitizer absorbing either in the blue or UV region, and an onium salt with weak coordinating anion resulted in formation of conjugate acid (con-H+). That was namely Ivocerin (di(4-methoxybenzoyl)diethylgermane), ITX (2-iso-propyl thioxanthone), anthracene, pyrene, rubrene, camphore quinone, and a strong fluorescent coumarin (1,1,6,6,8-pentamethyl-2,3,5,6-tetrahyhdro-1H,4H-11-oxa-3a-aza-benzo[de]anthracene-10-one). Quantification occurred by treatment with Rhodamine B lactone whose color switched to intensive red after photolytic formation of con-H+. Exposure with a NIR laser at 980 nm resulted in less con-H+ compared to 395 nm where all sensitizers absorb radiation. UCNP did not mainly interfered formation of con-H+. The different rates obtained in both experiments responsibly explain the failure and success to initiate polymerization of epoxides applying ether 980 nm or 395 nm excitation, respectively. 相似文献
153.
Dr. Dennis Rottschäfer Beate Neumann Dr. Hans-Georg Stammler Dr. Tetiana Sergeieva Dr. Diego M. Andrada Dr. Rajendra S. Ghadwal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(9):3055-3064
Herein, we report the first 1,4-diphosphinine-1,4-diide compound [(ADCPh)P]2 ( 5-Ph ) (ADCPh=PhC{(NDipp)C}2; Dipp=2,6-iPr2C6H3) derived from an anionic dicarbene (ADCPh) as a red crystalline solid. Compound 5-Ph containing a 16π-electron planar fused-tricyclic ring system was obtained by the 4e reduction of [(ADCPh)PCl2]2 ( 4-Ph ) with Mg (or KC8) in a quantitative yield. Experimental and computational results imply that the central 8π-electrons C4P2 ring of 5-Ph , which is fused between two 6π-electrons C3N2 aromatic rings, is antiaromatic. Thus, each of the phosphorus atoms of 5-Ph has two electron-lone-pairs, one in a p-type orbital is in conjugation with the C=C bonds of the C4P2 ring, while the second resides in a σ-symmetric orbital. This can be shown with the gold complex [(ADCPh)P(AuCl)2]2 ( 6-Ph ) obtained by reacting 5-Ph with (Me2S)AuCl. A mixture of 5-Ph and 4-Ph undergoes comproportionation in the presence of MgCl2 to form the intermediate oxidation state compound [(ADCAr)P]2(MgCl4) ( 7-Ph ), which is an aromatic species. 相似文献
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156.
Mechanistic Study of the Role of Primary Amines in Precursor Conversions to Semiconductor Nanocrystals at Low Temperature
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Dr. Kui Yu Dr. Xiangyang Liu Queena Y. Chen Prof. Huaqing Yang Prof. Mingli Yang Xinqin Wang Prof. Xin Wang Dr. Hong Cao Dr. Dennis M. Whitfield Prof. Changwei Hu Dr. Ye Tao 《Angewandte Chemie (International ed. in English)》2014,53(27):6898-6904
Primary alkyl amines (RNH2) have been empirically used to engineer various colloidal semiconductor nanocrystals (NCs). Here, we present a general mechanism in which the amine acts as a hydrogen/proton donor in the precursor conversion to nanocrystals at low temperature, which was assisted by the presence of a secondary phosphine. Our findings introduce the strategy of using a secondary phosphine together with a primary amine as new routes to prepare high‐quality NCs at low reaction temperatures but with high particle yields and reproducibility and thus, potentially, low production costs. 相似文献
157.
Potassium 1,1′‐Dinitramino‐5,5′‐bistetrazolate: A Primary Explosive with Fast Detonation and High Initiation Power
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Dennis Fischer Prof. Dr. Thomas M. Klapötke Dr. Jörg Stierstorfer 《Angewandte Chemie (International ed. in English)》2014,53(31):8172-8175
Adequate primary explosives such as lead azide mostly contain toxic ingredients, which have to be replaced. A new candidate that shows high potential, potassium 1,1′‐dinitramino‐5,5′‐bistetrazolate (K2DNABT), was synthesized by a sophisticated synthetic procedure based on dimethylcarbonate and glyoxal. It was intensively characterized for its chemical (X‐ray diffraction, EA, NMR and vibrational spectroscopy) and physico‐chemical properties (sensitivity towards impact, friction, and electrostatic, DSC). The obtained primary explosive combines good thermal stability with the desired mechanical stability. Owing to its high heat of formation (326 kJ mol?1) and density (2.11 g cm?3), impressive values for its detonation velocity (8330 m s?1) and pressure (311 kbar) were computed. Its superior calculated performance output was successfully confirmed and demonstrated by different convenient energetic test methods. 相似文献
158.
Inside Cover: Fluoride‐Bridged {GdIII3MIII2} (M=Cr,Fe, Ga) Molecular Magnetic Refrigerants (Angew. Chem. Int. Ed. 9/2014)
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159.
Patrick J. Whitham Dennis P. Strommen Sandra Lundell Lisa D. Lau Rene Rodriguez 《Plasma Chemistry and Plasma Processing》2014,34(4):755-766
The plasma enhanced chemical vapor depositions of germanium chalcogenide thin films from germanium tetrachloride, hydrogen sulfide and alkyl chalcogenides were studied to determine the viability of these reagents for thin film deposition. Hydrogen sulfide is a commonly used reagent for this technique and was used to determine optimal reaction conditions for thin film deposition. Germanium tetrachloride, alkylsulfides and alkylselenides were also employed because of their lower potential toxicities and higher availabilities compared to their more typical congeners: germane, hydrogen sulfide and hydrogen selenide in the formation of germanium chalcogenides. Alkylsulfides were found to be unsuitable for the deposition of germanium sulfides, however alkylselenide precursors were used successfully for the deposition of germanium selenides. The relative mass flow rates, reactor pressure, substrate temperature and plasma power density were studied for their effects on germanium chalcogenide deposition. These parameters affected the composition, deposition rate, film quality, and spectroscopic properties of the deposited films. 相似文献
160.
Dr. Yongxin Li Pan Sun Luyang Zhao Prof. Xuehai Yan Prof. Dennis K. P. Ng Prof. Pui-Chi Lo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(51):23428-23438
A facile approach to assemble catalase-like photosensitizing nanozymes with a self-oxygen-supplying ability was developed. The process involved Fe3+-driven self-assembly of fluorenylmethyloxycarbonyl (Fmoc)-protected amino acids. By adding a zinc(II) phthalocyanine-based photosensitizer (ZnPc) and the hypoxia-inducible factor 1 (HIF-1) inhibitor acriflavine (ACF) during the Fe3+-promoted self-assembly of Fmoc-protected cysteine (Fmoc-Cys), the nanovesicles Fmoc-Cys/Fe@Pc and Fmoc-Cys/Fe@Pc/ACF were prepared, which could be disassembled intracellularly. The released Fe3+ could catalyze the transformation of H2O2 enriched in cancer cells to oxygen efficiently, thereby ameliorating the hypoxic condition and promoting the photosensitizing activity of the released ZnPc. With an additional therapeutic component, Fmoc-Cys/Fe@Pc/ACF exhibited higher in vitro and in vivo photodynamic activities than Fmoc-Cys/Fe@Pc, demonstrating the synergistic effect of ZnPc and ACF. 相似文献