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101.
Optics and Spectroscopy - This contribution reports on the characterization of laser-induced plasma generated from the surface of magnesium oxide dispersed in Poly (vinyl alcohol) (MgO/PVA) pellet... 相似文献
102.
Dr. Peng Xu Dr. Da Zhao Dr. Florian Berger Aboubakr Hamad Dr. Jens Rickmeier Roland Petzold Mykhailo Kondratiuk Kostiantyn Bohdan Prof. Dr. Tobias Ritter 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(5):1972-1976
Site-selective functionalization of C−H bonds in small complex molecules is a long-standing challenge in organic chemistry. Herein, we report a broadly applicable and site-selective aromatic C−H dibenzothiophenylation reaction. The conceptual advantage of this transformation is further demonstrated through the two-step C−H [18F]fluorination of a series of marketed small-molecule drugs. 相似文献
103.
Several distributions of interest in chromatography were studied. In each case, the moments up to 4th moment were evaluated and the skew and the excess were deduced. The distributions studied in this article are the normal, continuous Poisson, discrete Poisson, exponentially modified normal, and exponentially modified Poisson distributions. 相似文献
104.
Burley GA Avent AG Gol'dt IV Hitchcock PB Al-Matar H Paolucci D Paolucci F Fowler PW Soncini A Street JM Taylor R 《Organic & biomolecular chemistry》2004,2(3):319-329
A series of trannulene (all-trans annulene) derivatives of [60]fullerene have been prepared by reacting C(60)F(18) with methanetricarboxylate esters that incorporate a range of photoactive functions. All the compounds have the intense emerald-green colour of fullerene trannulenes, characterised by strong bands at ca. 612 and 667 nm. Single crystal X-ray studies show that the packing varies with the nature of the addend, attributable to differing steric effects. UV/vis absorption spectra display transitions of the respective fullerene and addend models, indicating absence of electronic interactions between them in the ground state. These now provide an extensive series for testing photoactive (light-harvesting) properties, with the exceptional properties of having strong visible light absorption. Their exceptional stability is attributed to the 18[small pi] aromatic circuit, inability to undergo nucleophilic substitution without disrupting this circuit, and a curved cage region that is shielded to reagents by the three bulky addends. 相似文献
105.
M. Hamadène F. Balegroune A. Guehria-Laïdoudi J. Grannec J. Ravez 《Journal of chemical crystallography》2006,36(1):1-5
Reaction of anhydrous binary fluorides LiF and InF3 in sealed platinum tube at the temperature gradient 680/670°C yields α-Li3InF6. This low-temperature form crystallizes in the space group P21/m with the cell dimensions a = 4.797(3) Å, b = 8.679(1) Å, c = 10.366(1) Å and β = 90.90(1)°. The framework is built from InF6 and LiF6 octahedra, beside [Li2F6] bitetrahedra. The b-axis seems to be the backbone in the structural features. Running along it, zigzag anionic chains , resulting from one—edge shared [Li2F10] groups and double files of single InF6 octahedra sharing common corners with [Li2F6], create an approximately hexagonally packed framework in the plane (1 0 0). The antiferroelectric behaviour evident from dielectric studies is confirmed by the antiparallel displacements of In and Li atoms from octahedral centres. This structure is mainly featured by the disorder observed in the lightest atoms. These atoms, which exhibit two kinds of environments, have been refined as two partially occupied sites for the tetrahedral one. Within the Li3MF6 compounds (M: trivalent or 3d element), this new structure reveals unexpected structural features, inducing its ferroic properties. 相似文献
106.
N‐[(5‐Cyano‐2‐oxoimidazolidin‐4‐yl)‐iminomethyl]‐p‐toluensulfonamide 3 was prepared in fairly good yield by the base catalyzed cyclisation of N‐[(Z)‐2‐amino‐1,2‐dicycanovinylcarbamoyl]‐p‐toluenesulfon‐amide 2 . The N‐[(Z)‐2‐amino‐1,2‐dicycanovinyl carbamoyl]‐p‐toluenesulfonamide 2 was reacted readily with two molar amount of p‐nitrobenzaldehyde at room temperature in the presence of base to give 7,8‐dihy‐dro‐2‐(4‐nitrophenyl)‐8‐oxo‐9‐tosylpurine‐6‐carboxamide 8 . Thiation of compounds 3 and 8 using Lawesson's reagent in tetrahydrofuran gave novel thioimidazoles 4, 5 , and 6 and thiopurines 9, 10 , and 11 , which have been characterized spectroscopically. 相似文献
107.
Hamad A. Al-Khamees 《中国化学会会志》1995,42(6):947-951
N-(1,3-dimethyl-1H-2,3-dihydrobenzimidazol-2-y]idene)-acetamido derivatives were prepared and evaluated for antiarrhythmic activity. 相似文献
108.
Modelling a Linker Mix‐and‐Match Approach for Controlling the Optical Excitation Gaps and Band Alignment of Zeolitic Imidazolate Frameworks 下载免费PDF全文
Dr. Ricardo Grau‐Crespo Alex Aziz Angus W. Collins Dr. Rachel Crespo‐Otero Dr. Norge C. Hernández Dr. L. Marleny Rodriguez‐Albelo Dr. A. Rabdel Ruiz‐Salvador Prof. Dr. Sofia Calero Dr. Said Hamad 《Angewandte Chemie (International ed. in English)》2016,55(52):16012-16016
Tuning the electronic structure of metal–organic frameworks is the key to extending their functionality to the photocatalytic conversion of absorbed gases. Herein we discuss how the band edge positions in zeolitic imidazolate frameworks (ZIFs) can be tuned by mixing different imidazole‐based linkers within the same structure. We present the band alignment for a number of known and hypothetical Zn‐based ZIFs with respect to the vacuum level. Structures with a single type of linker exhibit relatively wide band gaps; however, by mixing linkers of a low‐lying conduction edge with linkers of a high‐lying valence edge, we can predict materials with ideal band positions for visible‐light water splitting and CO2 reduction photocatalysis. By introducing copper in the tetrahedral position of the mixed‐linker ZIFs, it would be possible to increase both photo‐absorption and the electron–hole recombination times. 相似文献
109.
110.