共查询到20条相似文献,搜索用时 546 毫秒
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Dirk Grote Dr. Christopher Finke Simone Kossmann Frank Neese Prof. Dr. Wolfram Sander Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(15):4496-4506
The photochemistry of 2‐iodo‐3,4,5,6‐tetrafluorophenyl azide ( 7 d ) has been investigated in argon and neon matrices at 4 K, and the products characterized by IR and EPR spectroscopy. The primary photochemical step is loss of a nitrogen molecule and formation of phenyl nitrene 1 d . Further irradiation with UV or visible light results in mixtures of 1 d with azirine 5 d ′, ketenimine 6 d ′, nitreno radical 2 d , and azirinyl radical 9 . The relative amounts of these products strongly depend on the matrix and on the irradiation conditions. Nitreno radical 2 d with a quartet ground state was characterized by EPR spectroscopy. Electronic structure calculations in combination with the experimental results allow for a detailed understanding of the properties of this unusual new type of organic high‐spin molecules. 相似文献
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Inside Back Cover: Self‐Assembly of Measles Virus Nucleocapsid‐like Particles: Kinetics and RNA Sequence Dependence (Angew. Chem. Int. Ed. 32/2016) 下载免费PDF全文
Dr. Sigrid Milles Dr. Malene Ringkjøbing Jensen Dr. Guillaume Communie Damien Maurin Dr. Guy Schoehn Prof. Rob W. H. Ruigrok Dr. Martin Blackledge 《Angewandte Chemie (International ed. in English)》2016,55(32):9441-9441
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Back Cover: Breslow Intermediates from Aromatic N‐Heterocyclic Carbenes (Benzimidazolin‐2‐ylidenes,Thiazolin‐2‐ylidenes) (Angew. Chem. Int. Ed. 27/2018) 下载免费PDF全文
Dr. Mathias Paul Dr. Nils E. Schlörer Dr. Jörg‐M. Neudörfl Prof. Dr. Albrecht Berkessel 《Angewandte Chemie (International ed. in English)》2018,57(27):8332-8332
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Solution‐crystallization and related phenomena in 9,9‐dialkyl‐fluorene polymers. II. Influence of side‐chain structure 下载免费PDF全文
Aleksandr Perevedentsev Paul N. Stavrinou Paul Smith Donal D. C. Bradley 《Journal of Polymer Science.Polymer Physics》2015,53(21):1492-1506
Solution‐crystallization is studied for two polyfluorene polymers possessing different side‐chain structures. Thermal analysis and temperature‐dependent optical spectroscopy are used to clarify the nature of the crystallization process, while X‐ray diffraction and scanning electron microscopy reveal important differences in the resulting microstructures. It is shown that the planar‐zigzag chain conformation termed the β‐phase, which is observed for certain linear‐side‐chain polyfluorenes, is necessary for the formation of so‐called polymer‐solvent compounds for these polymers. Introduction of alternating fluorene repeat units with branched side‐chains prevents formation of the β‐phase conformation and results in non‐solvated, i.e. melt‐crystallization‐type, polymer crystals. Unlike non‐solvated polymer crystals, for which the chain conformation is stabilized by its incorporation into a crystalline lattice, the β‐phase conformation is stabilized by complexation with solvent molecules and, therefore, its formation does not require specific inter‐chain interactions. The presented results clarify the fundamental differences between the β‐phase and other conformational/crystalline forms of polyfluorenes. © 2015 The Authors. Journal of Polymer Science Part B: Polymer Physics published by Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1492–1506 相似文献
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Inside Back Cover: Initial Carbon–Carbon Bond Formation during the Early Stages of the Methanol‐to‐Olefin Process Proven by Zeolite‐Trapped Acetate and Methyl Acetate (Angew. Chem. Int. Ed. 51/2016) 下载免费PDF全文
Dr. Abhishek Dutta Chowdhury Dr. Klaartje Houben Dr. Gareth T. Whiting Prof. Dr. Mohamed Mokhtar Prof. Dr. Abdullah M. Asiri Prof. Dr. Shaeel A. Al‐Thabaiti Prof. Dr. Suliman N. Basahel Prof. Dr. Marc Baldus Prof. Dr. Bert M. Weckhuysen 《Angewandte Chemie (International ed. in English)》2016,55(51):15929-15929
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Frontispiece: Matrix‐Free DNP‐Enhanced NMR Spectroscopy of Liposomes Using a Lipid‐Anchored Biradical 下载免费PDF全文
Dr. Carlos Fernández‐de‐Alba Dr. Hiroki Takahashi Alexandre Richard Yves Chenavier Dr. Lionel Dubois Vincent Maurel Dr. Daniel Lee Dr. Sabine Hediger Dr. Gaël De Paëpe 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(12)
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Back Cover: Gas‐Phase Peptide Structures Unraveled by Far‐IR Spectroscopy: Combining IR‐UV Ion‐Dip Experiments with Born–Oppenheimer Molecular Dynamics Simulations (Angew. Chem. Int. Ed. 14/2014) 下载免费PDF全文
Sander Jaeqx Prof. Dr. Jos Oomens Dr. Alvaro Cimas Prof. Dr. Marie‐Pierre Gaigeot Dr. Anouk M. Rijs 《Angewandte Chemie (International ed. in English)》2014,53(14):3750-3750
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Cover Picture: Selective Oxidation of Alkyl‐Substituted Polyaromatics Using Ruthenium‐Ion‐Catalyzed Oxidation (Chem. Eur. J. 11/2015) 下载免费PDF全文
Ewa Nowicka Meenakshisundaram Sankar Robert L. Jenkins David W. Knight David J. Willock Graham J. Hutchings Manuel Francisco Stuart H. Taylor 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(11):4165-4165
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The recent advances in the study of light emission from matter induced by synchrotron radiation: X‐ray excited optical luminescence (XEOL) in the energy domain and time‐resolved X‐ray excited optical luminescence (TRXEOL) are described. The development of these element (absorption edge) selective, synchrotron X‐ray photons in, optical photons out techniques with time gating coincide with advances in third‐generation, insertion device based, synchrotron light sources. Electron bunches circulating in a storage ring emit very bright, widely energy tunable, short light pulses (<100 ps), which are used as the excitation source for investigation of light‐emitting materials. Luminescence from silicon nanostructures (porous silicon, silicon nanowires, and Si–CdSe heterostructures) is used to illustrate the applicability of these techniques and their great potential in future applications. 相似文献
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Ping Ding Dorith Wunnicke Prof. Heinz‐Jürgen Steinhoff Prof. Frank Seela 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(48):14385-14396
Nucleobase‐directed spin‐labeling by the azide‐alkyne ‘click’ (CuAAC) reaction has been performed for the first time with oligonucleotides. 7‐Deaza‐7‐ethynyl‐2′‐deoxyadenosine ( 1 ) and 5‐ethynyl‐2′‐deoxyuridine ( 2 ) were chosen to incorporate terminal triple bonds into DNA. Oligonucleotides containing 1 or 2 were synthesized on a solid phase and spin labeling with 4‐azido‐2,2,6,6‐tetramethylpiperidine 1‐oxyl (4‐azido‐TEMPO, 3 ) was performed by post‐modification in solution. Two spin labels ( 3 ) were incorporated with high efficiency into the DNA duplex at spatially separated positions or into a ‘dA‐dT’ base pair. Modification at the 5‐position of the pyrimidine base or at the 7‐position of the 7‐deazapurine residue gave steric freedom to the spin label in the major groove of duplex DNA. By applying cw and pulse EPR spectroscopy, very accurate distances between spin labels, within the range of 1–2 nm, were measured. The spin–spin distance was 1.8±0.2 nm for DNA duplex 17 ( dA*7,10 ) ?11 containing two spin labels that are separated by two nucleotides within one individual strand. A distance of 1.4±0.2 nm was found for the spin‐labeled ‘dA‐dT’ base pair 15 ( dA*7 ) ?16 ( dT*6 ). The ‘click’ approach has the potential to be applied to all four constituents of DNA, which indicates the universal applicability of the method. New insights into the structural changes of canonical or modified DNA are expected to provide additional information on novel DNA structures, protein interaction, DNA architecture, and synthetic biology. 相似文献
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Self‐Assembly of Measles Virus Nucleocapsid‐like Particles: Kinetics and RNA Sequence Dependence 下载免费PDF全文
Dr. Sigrid Milles Dr. Malene Ringkjøbing Jensen Dr. Guillaume Communie Damien Maurin Dr. Guy Schoehn Prof. Rob W. H. Ruigrok Dr. Martin Blackledge 《Angewandte Chemie (International ed. in English)》2016,55(32):9356-9360