Ingo Hartenbach  Isabelle Gerlach  Thomas Schleid 《无机化学与普通化学杂志》2019,645(3):149-152

In an attempt to synthesize LiEu₃S₃[SiS₄] utilizing elemental europium and sulfur as well as SiS₂ and an excess of LiCl as flux and lithium source, dark red, platelet‐shaped single crystals of Li₃Eu₆[SiS₄]₄ were obtained. This new compound crystallizes in the cubic space group I4 3d (a = 1369.22(5) pm) with four formula units per unit cell. Both the Li⁺ and the Si⁴⁺ cations are surrounded by four sulfide anions. The [SiS₄]^4– tetrahedra show merely a slight trigonal distortion, while the [LiS₄]^7– units are best described as flattened bisphenoids. The europium cations exhibit an eightfold, rather irregular coordination environment by eight S^2– anions and have to be regarded mixed‐valent with a +2:+3 charge‐ratio of 5:1 in order to gain electroneutrality. The lack of an inversion center is caused by the [SiS₄]^4– tetrahedra being stacked exclusively top up along [111] in this acentric crystal structure.  相似文献   

    

Anne‐Sophie Marques  Thibaut Duhail  Jrome Marrot  Isabelle Chataigner  Vincent Coeffard  Guillaume Vincent  Xavier Moreau 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(29):10074-10078

We report an unprecedented domino polycyclization from readily available 2,4‐dienals and cyclic α,β‐unsaturated imines that is initiated by an iso‐Nazarov reaction. This Brønsted acid promoted reaction enables the concomitant formation of four bonds, three cycles, and four contiguous stereogenic centers to yield elaborated structures in a single operation. A range of fused hexacyclic molecules is obtained in a highly diastereoselective manner.  相似文献   

    

Julian Teichmann  Chantal Kunkel  Isabelle Georg  Dr. Maximilian Moxter  Tobias Santowski  Dr. Michael Bolte  Dr. Hans-Wolfram Lerner  Dr. Stefan Bade  Prof. Dr. Matthias Wagner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(11):2740-2744

Trichlorosilylated tetrelides [(Cl₃Si)₃E]⁻ have been prepared by adding 1 equiv of a soluble Cl⁻ salt to (Cl₃Si)₄Si (E=Si) or 4 Si₂Cl₆/GeCl₄ (E=Ge). To assess their donor qualities, the anions [(Cl₃Si)₃E]⁻ (E=C, Si, Ge) have been treated with BCl₃, AlCl₃, and GaCl₃. Both BCl₃ and GaCl₃ give 1:1 adducts with the anionic centers. AlCl₃ leads to Cl⁻ abstraction from [(Cl₃Si)₃E]⁻ with formation of (Cl₃Si)₄E (E=Si or Ge). (Cl₃Si)₄Ge is cleanly converted to the perhydrogenated (H₃Si)₄Ge by use of Li[AlH₄]. Another case of Cl⁻ abstraction was observed for [(Cl₃Si)₃Ge ⋅ GaCl₃]⁻, which reacts with GaCl₃ to afford the neutral dimer [(Cl₃Si)₃Ge−GaCl₂]₂.  相似文献   

    

Hadjer Ouaddah  Isabelle Prichaud  Damien Barakel  Olivier Palais  Marisa Di Sabatino  Guillaume Reinhart  Gabrielle Regula  Nathalie Mangelinck-Noël 《physica status solidi (a)》2019,216(17)

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Max Hohenschutz  Dr. Isabelle Grillo  Dr. Olivier Diat  Dr. Pierre Bauduin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(21):8161-8165

Recently, nanometric ions were shown to adsorb to hydrated neutral surfaces and to bind to the cavities of macrocyclic molecules with an unexpectedly strong affinity arising from a solvent-mediated effect named superchaotropicity. We show here that nano-ions at low concentrations (μm range), similarly to anionic surfactants, induce the spontaneous transformation of a swollen lyotropic lamellar phase of non-ionic surfactant into a vesicle phase. This transition occurs when the neutral lamellae acquire charges, either by adsorption of the nano-ions onto, or by anchoring of the ionic surfactant into the lamellae. In contrast to ionic surfactants, nano-ions strongly dehydrate the neutral surfactant assemblies. As a conclusion, these purely inorganic nanometric ions act as alternatives to the widely used organic ionic surfactants.  相似文献   

    

Isabelle Kroner  Dr. Maik Becker  Prof. Dr. Thomas Turek 《ChemElectroChem》2020,7(21):4284-4284

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Isabelle Gallagher  Mitsuo Higaki  Yasunori Maekawa 《Mathematische Nachrichten》2019,292(2):273-308

We study the two‐dimensional stationary Navier–Stokes equations describing flows around a rotating disk. The existence of unique solutions is established for any rotating speed, and qualitative effects of a large rotation are described precisely by exhibiting a boundary layer structure and an axisymmetrization of the flow.  相似文献   

    

Joseph Kioseoglou  Hoang‐Long Le‐Tran  Stefanos Giaremis  Isabelle Gelard  Thierry Ouisse  Didier Chaussende  Eirini Sarigiannidou 《physica status solidi b》2019,256(10)

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Nicolas Canu  Dr. Pascal Belin  Dr. Robert Thai  Dr. Isabelle Correia  Prof. Olivier Lequin  Dr. Jérôme Seguin  Dr. Mireille Moutiez  Dr. Muriel Gondry 《Angewandte Chemie (International ed. in English)》2018,57(12):3118-3122

The manipulation of natural product biosynthetic pathways is a powerful means of expanding the chemical diversity of bioactive molecules. 2,5‐diketopiperazines (2,5‐DKPs) have been widely developed by medicinal chemists, but their biological production is yet to be exploited. We introduce an in vivo method for incorporating non‐canonical amino acids (ncAAs) into 2,5‐DKPs using cyclodipeptide synthases (CDPSs), the enzymes responsible for scaffold assembly in many 2,5‐DKP biosynthetic pathways. CDPSs use aminoacyl‐tRNAs as substrates. We exploited the natural ability of aminoacyl‐tRNA synthetases to load ncAAs onto tRNAs. We found 26 ncAAs to be usable as substrates by CDPSs, leading to the enzymatic production of approximately 200 non‐canonical cyclodipeptides. CDPSs constitute an efficient enzymatic tool for the synthesis of highly diverse 2,5‐DKPs. Such diversity could be further expanded, for example, by using various cyclodipeptide‐tailoring enzymes found in 2,5‐DKP biosynthetic pathways.  相似文献   

    

Dr. Elena Meirzadeh  Shiri Dishon  Dr. Isabelle Weissbuch  Dr. David Ehre  Prof. Dr. Meir Lahav  Prof. Dr. Igor Lubomirsky 《Angewandte Chemie (International ed. in English)》2018,57(18):4965-4969

Metastable polymorphs commonly emerge when the formation of the stable analogues is inhibited by using different solvents or auxiliaries. Herein, we report that when glycine is grown in aqueous solutions in the presence of low concentrations of different co‐solvents, only alcohols and acetone, unlike water and acetic acid, are selectively incorporated in minute amounts within the bulk of the α‐polymorph. These findings demonstrate that although water binds more strongly to the growing face of the crystal, alcohols and acetone are exclusively incorporated, and thus serve as efficient inhibitors of this polymorph, leading to the precipitation of the β‐form. These solvents then create polar domains detectable by pyroelectric measurements and impedance spectroscopy. These results suggest that in the control of crystal polymorphism with co‐solvents, one should consider also the different desolvation rates in addition to the energy of binding to the growing faces of the crystal.  相似文献