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排序方式: 共有119条查询结果,搜索用时 15 毫秒
1.
2.
Romana Pajkert Tobias Böttcher Maksym Ponomarenko Matthias Bremer Gerd-Volker Röschenthaler 《Tetrahedron》2013
A series of novel push–pushI and push–pullII carbene-stabilized complexes of phosphorus(V) fluorides bearing substituents with liquid-crystalline properties were synthesized by the oxidative addition of difluoroamines to phosphorus(III) halides. These octahedral complexes were characterized by NMR spectroscopy and X-ray analysis. 相似文献
3.
This work is devoted to the elaboration of a practical scheme for the synthesis of dendritic derivatives of gallic acid containing a carboxylate-ω-alkylphosphonic acid group and three terminal promesogenic substituents. Two synthetic strategies toward the target compounds were examined that differ in the sequence of the introduction of the promesogenic units and ω-alkylphosphonic group. 相似文献
4.
Kyle M. McCall Bogdan M. Benin Michael Wörle Thomas Vonderach Detlef Günther Maksym V. Kovalenko 《Helvetica chimica acta》2021,104(1):e2000206
Inorganic, lead-free metal halides are widely sought after following the rise of the halide perovskites as outstanding optoelectronic materials, due to their enhanced stability and reduced toxicity. Herein, we report on the solvothermal synthesis of Rb7Sb3Br16, which exhibits a 0D structure comprised of [SbBr6]3− octahedra and edge-sharing bioctahedra [Sb2Br10]4− dimers that order into layers along the c-axis. This all-inorganic material is air-stable and exhibits weak orange photoluminescence (PL) at room temperature. Low-temperature PL and PL excitation (PLE) measurements reveal the presence of two distinct emission bands that originate from these structural units, with the high-energy emission quenching as temperature rises beyond 150 K. We are also able to obtain Rb7Bi3Br16 and Rb7Bi3I16 which both crystallize in orthorhombic symmetry, with Rb7Bi3Br16 presenting weak low-temperature luminescence while Rb7Bi3I16 is non-luminescent. This work expands the library of emissive inorganic metal halides and provides further evidence for the efficacy of low-dimensional Sb−X luminescent centers based on octahedral and edge-sharing [Sb2X10]4− dimers. 相似文献
5.
Dr. Paul S. Wheatley Dr. Pavla Chlubná‐Eliášová Dr. Heather Greer Prof. Wuzong Zhou Dr. Valerie R. Seymour Dr. Daniel M. Dawson Prof. Sharon E. Ashbrook Dr. Ana B. Pinar Dr. Lynne B. McCusker Dr. Maksym Opanasenko Prof. Jiří Čejka Prof. Russell E. Morris 《Angewandte Chemie (International ed. in English)》2014,53(48):13210-13214
Zeolites are important materials whose utility in industry depends on the nature of their porous structure. Control over microporosity is therefore a vitally important target. Unfortunately, traditional methods for controlling porosity, in particular the use of organic structure‐directing agents, are relatively coarse and provide almost no opportunity to tune the porosity as required. Here we show how zeolites with a continuously tuneable surface area and micropore volume over a wide range can be prepared. This means that a particular surface area or micropore volume can be precisely tuned. The range of porosity we can target covers the whole range of useful zeolite porosity: from small pores consisting of 8‐rings all the way to extra‐large pores consisting of 14‐rings. 相似文献
6.
Bartosz Szyszko Paweł Rymut Maksym Matviyishyn Agata Białońska Lechosław Latos-Grażyński 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(45):20312-20321
Di-2,7-naphthihexaphyrin(1.1.1.1.1.1), a non-aromatic carba-analogue of the hexaphyrin(1.1.1.1.1.1), incorporating two built-in 2,7-naphthylene moieties was synthesized as two separate, conformationally locked stereoisomers. Both conformers followed complex protonation pathways involving structurally different species, which can be targeted under kinetic and thermodynamic control. The neutralization of the ultimate dicationic product, accessible from both stereoisomers of the free base, allowed to realize the complex conformational switching cycle involving six structurally different species. 相似文献
7.
Marcel Aebli Bogdan M. Benin Kyle M. McCall Viktoriia Morad Debora Thöny Hansjörg Grützmacher Maksym V. Kovalenko 《Helvetica chimica acta》2020,103(7):e2000080
Inorganic lead halide perovskites have gained immense scientific interest for optoelectronic applications. In this work, we present a one-dimensional polymorph of cesium lead bromide (δ-CsPbBr3) synthesized through a simple anion-exchange reaction, wherein distorted edge-sharing PbBr6 octahedra form 1D chains isolated by Cs ions. δ-CsPbBr3 was characterized by Raman spectroscopy, X-ray diffraction, 207Pb and 133Cs solid-state NMR, and by optical emission and absorption spectroscopies. This non-perovskite material irreversibly transforms into the well-known three-dimensional perovskite phase (γ-CsPbBr3) upon heating to above 151 °C. The indirect bandgap was determined by absorption measurements and calculation to be 2.9 eV. δ-CsPbBr3 exhibits broadband yellow photoluminescence with a quantum yield of 3.2 %±0.2 % at room temperature and 95 %±5 % at 77 K, and this emission is attributed to the recombination of self-trapped excitons. This study emphasizes that the metastable δ-CsPbBr3 may be a persistent, concomitant phase in Cs−Pb-Br-containing materials systems, such as those used in solar cells and LEDs, and it showcases the characterization tools used for its detection. 相似文献
8.
Maksym S. Kazunin Oleksii Yu. Voskoboynik Inna S. Nosulenko Galina G. Berest Sergiy V. Kholodniak Boris O. Pryymenko Sergiy I. Kovalenko 《Journal of heterocyclic chemistry》2020,57(1):268-280
The synthesis of 6-(2-hydroxy-2-aryl (heteryl)ethyl)-1-methylpteridine-2,4,7(1H,3H,8H)-triones by the reduction of the corresponding ketones and the peculiarities of conversion of the synthesized alcohols to (E)-1-methyl-6-(2-aryl (heteryl)ethenyl)pteridine-2,4,7(1H,3H,8H)-triones was reported. The mechanism of monomolecular elimination that occurred in the presence of hydrogen halides was discussed, namely, the competitive formation of an energy-efficient conjugated system by deprotonation of a stable benzyl-type carbocation. Alternative synthesis methods of pteridine-2,4,7(1H,3H,8H)-triones were developed. Abovementioned approach involved [4+2]-cyclocondensation of 1-methyl-5,6-diaminouracil to 2-oxo-4-R-but-3-enoic acids and Knoevenagel condensation of 1,6-dimethylpteridine-2,4,7(1H,3H,8H)-trione with aromatic aldehydes. The antiradical, antimicrobial, and antifungal activities were studied for the synthesized compounds. 相似文献
9.
Serhii Krykun Maksym Dekhtiarenko David Canevet Vincent Carr Frdric Aubriet Eric Levillain Magali Allain Zoia Voitenko Marc Sall Sbastien Goeb 《Angewandte Chemie (International ed. in English)》2020,59(2):716-720
Developing methodologies for on‐demand control of the release of a molecular guest requires the rational design of stimuli‐responsive hosts with functional cavities. While a substantial number of responsive metallacages have already been described, the case of coordination‐tweezers has been less explored. Herein, we report the first example of a redox‐triggered guest release from a metalla‐assembled tweezer. This tweezer incorporates two redox‐active panels constructed from the electron‐rich 9‐(1,3‐dithiol‐2‐ylidene)fluorene unit that are facing each other. It dimerizes spontaneously in solution and the resulting interpenetrated supramolecular structure can dissociate in the presence of an electron‐poor planar unit, forming a 1:1 host–guest complex. This complex dissociates upon tweezer oxidation/dimerization, offering an original redox‐triggered molecular delivery pathway. 相似文献
10.
Valentin Chabert Lucille Babel Michael P. Füeg Maksym Karamash Edwin S. Madivoli Nelly Herault Joana M. Dantas Carlos A. Salgueiro Bernd Giese Katharina M. Fromm 《Angewandte Chemie (International ed. in English)》2020,59(30):12331-12336
Anaerobic microorganisms of the Geobacter genus are effective electron sources for the synthesis of nanoparticles, for bioremediation of polluted water, and for the production of electricity in fuel cells. In multistep reactions, electrons are transferred via iron/heme cofactors of c‐type cytochromes from the inner cell membrane to extracellular metal ions, which are bound to outer membrane cytochromes. We measured electron production and electron flux rates to 5×105 e s?1 per G. sulfurreducens. Remarkably, these rates are independent of the oxidants, and follow zero order kinetics. It turned out that the microorganisms regulate electron flux rates by increasing their Fe2+/Fe3+ ratios in the multiheme cytochromes whenever the activity of the extracellular metal oxidants is diminished. By this mechanism the respiration remains constant even when oxidizing conditions are changing. This homeostasis is a vital condition for living systems, and makes G. sulfurreducens a versatile electron source. 相似文献