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1.
Grant J. Sherborne Avetik G. Gevondian Ignacio Funes-Ardoiz Amit Dahiya Christoph Fricke Prof. Dr. Franziska Schoenebeck 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(36):15673-15678
Selective C –C couplings are powerful strategies for the rapid and programmable construction of bi- or multiaryls. To this end, the next frontier of synthetic modularity will likely arise from harnessing the coupling space that is orthogonal to the powerful Pd-catalyzed coupling regime. This report details the realization of this concept and presents the fully selective arylation of aryl germanes (which are inert under Pd0/PdII catalysis) in the presence of the valuable functionalities C−BPin, C−SiMe3, C−I, C−Br, C−Cl, which in turn offer versatile opportunities for diversification. The protocol makes use of visible light activation combined with gold catalysis, which facilitates the selective coupling of C−Ge with aryl diazonium salts. Contrary to previous light-/gold-catalyzed couplings of Ar–N2+, which were specialized in Ar–N2+ scope, we present conditions to efficiently couple electron-rich, electron-poor, heterocyclic and sterically hindered aryl diazonium salts. Our computational data suggest that while electron-poor Ar–N2+ salts are readily activated by gold under blue-light irradiation, there is a competing dissociative deactivation pathway for excited electron-rich Ar–N2+, which requires an alternative photo-redox approach to enable productive couplings. 相似文献
2.
Kerstin Mayer Jasmin V. Dums Christian B. Benda Wilhelm Klein Thomas F. Fssler 《Angewandte Chemie (International ed. in English)》2020,59(17):6800-6805
Polymeric [Bi]? in KBi?NH3 has planar zigzag chains with two‐connected Bi atoms and metallic properties, whereas KBi, which has helical chains of Bi atoms, is semiconducting. The isomerization of the Bi chain is induced by solvate molecules. In the novel layered solvate structure uncharged [KBi] layers are separated by intercalated NH3 molecules. These layers are a structural excerpt of the iso(valence)electronic CaSi, whose metallic properties arise from the planarity of the zigzag chain of Si atoms. Computational studies support this view, they show an anisotropic metallic behavior along the Bi chain. Electron delocalization is also found in the new cyclic anion [Bi6]4? isolated in K2[K(18‐crown‐6)]2[Bi6]?9 NH3. Although [Bi6]4? should exhibit one localized double bond, electron delocalization is observed in analogy to the lighter homologues [P6]4? and [As6]4?. Both compounds were characterized by single‐crystal X‐ray structure determination. 相似文献
3.
Catalytic and Atom‐Economic C
−C
Bond Formation: Alkyl Tantalum Ureates for Hydroaminoalkylation
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Rebecca C. DiPucchio Dr. Sorin‐Claudiu Roşca Prof. Laurel L. Schafer 《Angewandte Chemie (International ed. in English)》2018,57(13):3469-3472
Atom‐economic and regioselective C ?C bond formation has been achieved by rapid C?H alkylation of unprotected secondary arylamines with unactivated alkenes. The combination of Ta(CH2SiMe3)3Cl2, and a ureate N,O‐chelating‐ligand salt gives catalytic systems prepared in situ that can realize high yields of β‐alkylated aniline derivatives from either terminal or internal alkene substrates. These new catalyst systems realize C?H alkylation in as little as one hour and for the first time a 1:1 stoichiometry of alkene and amine substrates results in high yielding syntheses of isolated amine products by simple filtration and concentration. 相似文献
4.
Julia Holz Camilla Pfeffer Hualiang Zuo Dennis Beierlein Gunther Richter Elias Klemm Ren Peters 《Angewandte Chemie (International ed. in English)》2019,58(30):10330-10334
Gold nanoparticle catalysts are important in many industrial production processes. Nevertheless, for traditional C ?C cross‐coupling reactions they have been rarely used and Pd catalysts usually give a superior performance. Herein we report that in situ formed gold metal nanoparticles are highly active catalysts for the cross coupling of allylstannanes and activated alkylbromides to form C ?C bonds. Turnover numbers up to 29 000 could be achieved in the presence of active carbon as solid support, which allowed for convenient catalyst recovery and reuse. The present study is a rare case where a gold metal catalyst is superior to Pd catalysts in a cross‐coupling reaction of an organic halide and an organometallic reagent. 相似文献
5.
Hole or electron doping of phases prepared by topochemical reactions (e.g. anion deintercalation or anion‐exchange) is extremely challenging as these low‐temperature conversion reactions are typically very sensitive to the electron counts of precursor phases. Herein we report the successful hole and electron doping of the transition‐metal oxyhydride LaSr3NiRuO4H4 by first preparing precursors in the range LaxSr4?xNiRuO8 0.5<x<1.4 and then converting into the corresponding LaxSr4?xNiRuO4H4 phases. This is particularly noteworthy as the (Ni/Ru)H2 sheets in the LaxSr4?xNiRuO4H4 phases are structurally analogous to the CuO2 sheets in cuprate superconductors and hole doping (Ni1+/2+, Ru2+) or electron doping (Ni2+, Ru1+/2+) yields materials with partial occupancy in Ni/Ru –H 1s bands which are analogous to the partially occupied Cu –O 2p bands present in the CuO2 sheets of doped superconducting cuprates. 相似文献
6.
Shibo Xu Kazutaka Takamatsu Prof. Dr. Koji Hirano Prof. Dr. Masahiro Miura 《Angewandte Chemie (International ed. in English)》2018,57(36):11797-11801
A Ni(OAc)2‐catalyzed C?H coupling of 8‐aminoquinoline‐derived benzamides with epoxides has been developed. The reaction proceeds with concomitant removal of the 8‐aminoquinoline auxiliary to form the corresponding 3,4‐dihydroisocoumarins directly. Additionally, the nickel catalysis is stereospecific, and the cis‐ and trans‐epoxides are converted into the corresponding cis‐ and trans‐dihydroisocoumarins with retention of configuration, which is complementary to previously reported palladium catalysis. Moreover, while still preliminary, the C ?H functionalization is also achieved in the presence of modified NiCl2 catalysts. 相似文献
7.
Daniel E. Diaz David A. Quist Austin E. Herzog Andrew W. Schaefer Ioannis Kipouros Mayukh Bhadra Edward I. Solomon Kenneth D. Karlin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(49):17736-17740
The dioxygen reactivity of a series of TMPA‐based copper(I) complexes (TMPA=tris(2‐pyridylmethyl)amine), with and without secondary‐coordination‐sphere hydrogen‐bonding moieties, was studied at ?135 °C in 2‐methyltetrahydrofuran (MeTHF). Kinetic stabilization of the H‐bonded [( TMPA)CuII(O2.?)]+ cupric superoxide species was achieved, and they were characterized by resonance Raman (rR) spectroscopy. The structures and physical properties of [( TMPA)CuII(N3?)]+ azido analogues were compared, and the O2.? reactivity of ligand–CuI complexes when an H‐bonding moiety is replaced by a methyl group was contrasted. A drastic enhancement in the reactivity of the cupric superoxide towards phenolic substrates as well as oxidation of substrates possessing moderate C?H bond‐dissociation energies is observed, correlating with the number and strength of the H‐bonding groups. 相似文献
8.
Matthew V. Vollmer Dr. Jing Xie Ryan C. Cammarota Dr. Victor G. Young Jr. Dr. Eckhard Bill Prof. Laura Gagliardi Prof. Connie C. Lu 《Angewandte Chemie (International ed. in English)》2018,57(26):7815-7819
Formal nickelate(?I) complexes bearing Group 13 metalloligands (M=Al and Ga) were isolated. These 17 e? complexes were synthesized by one‐electron reduction of the corresponding Ni0→MIII precursors, and were investigated by single‐crystal X‐ray diffraction, EPR spectroscopy, and quantum chemical calculations. Collectively, the experimental and computational data support: 1) the strengthening of the Ni?M bond upon one‐electron reduction, and 2) the delocalization of the unpaired spin across the Ni and M atoms. An intriguing electronic configuration is revealed where three valence electrons occupy two σ‐type bonding interactions: Ni(3d )2→M and σ‐(Ni?M)1. The latter is an unusual Ni?M σ‐bonding molecular orbital that comprises primarily the Ni 4pz and M npz/ns atomic orbitals. 相似文献
9.
Franziska Karcher Matthias Uhl Tanja Geng Timo Jacob Rolf Schuster 《Angewandte Chemie (International ed. in English)》2023,62(22):e202301253
The formation of an appropriate solid electrolyte interphase (SEI) at the anode of a sodium battery is crucially dependent on the electrochemical stability of solvent and electrolyte at the redox potential of Na/Na+ in the respective system. In order to determine entropic contributions to the relative stability of the electrolyte solution, we measure the reaction entropy of Na metal deposition for diglyme (DG) and propylene carbonate (PC) based electrolyte solutions by electrochemical microcalorimetry at single electrodes. We found a large positive reaction entropy for Na+ deposition in DG of ΔR 234 J mol−1 K−1 (c.f.: ΔR 83 J mol−1 K−1), which signals substantial entropic destabilization of Na+ in DG by about 0.73 eV, thus increasing the stability of solvent and electrolyte relative to Na+ reduction. We attribute this strong entropic destabilization to a highly negative solvation entropy of Na+, due to the low dielectric constant and high freezing entropy of DG. 相似文献
10.
Structure and Composition of the 200 K‐Superconducting Phase of H2S at Ultrahigh Pressure: The Perovskite (SH−)(H3S+)
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Prof. Dr. Hongjun Xiang Prof. Dr. Annette Bussmann‐Holder Dr. Reinhard K. Kremer Prof. Dr. Arndt Simon Prof. Dr. Jürgen Köhler Prof. Dr. Myung‐Hwan Whangbo 《Angewandte Chemie (International ed. in English)》2016,55(11):3682-3684
At ultrahigh pressure (>110 GPa), H2S is converted into a metallic phase that becomes superconducting with a record Tc of approximately 200 K. It has been proposed that the superconducting phase is body‐centered cubic H3S (Im m, a=3.089 Å) resulting from the decomposition reaction 3 H2S→2 H3S+S. The analogy between H2S and H2O led us to a very different conclusion. The well‐known dissociation of water into H3O+ and OH? increases by orders of magnitude under pressure. H2S is anticipated to behave similarly under pressure, with the dissociation process 2 H2S→H3S++SH? leading to the perovskite structure (SH?)(H3S+). This phase consists of corner‐sharing SH6 octahedra with SH? ions at each A site (the centers of the S8 cubes). DFT calculations show that the perovskite (SH?)(H3S+) is thermodynamically more stable than the Im m structure of H3S, and suggest that the A site hydrogen atoms are most likely fluxional even at Tc . 相似文献
11.
Nanami Uemura Tsubasa Kobayashi Shintaro Yoshida Ya‐xin Li Karel Goossens Xiangbing Zeng Go Watanabe Takahiro Ichikawa 《Angewandte Chemie (International ed. in English)》2020,59(22):8445-8450
We report a new molecular‐design principle for creating double‐gyroid nanostructured molecular assemblies based on atropisomerization. Ionic amphiphiles containing two imidazolium rings close to each other were designed and synthesized. NMR data revealed that the rotation of the imidazolium rings is restricted, with an activation energy as high as 63 kJ mol?1 in DMSO‐d6 solution (DFT prediction for a model compound in the vacuum: 90–100 kJ mol?1). Due to the restricted rotation, the amphiphiles feature “double” atropisomeric axes in their ionic segments and form three stable atropisomers: meso, R, and S. These isomers co‐organize into ‐type bicontinuous cubic liquid‐crystalline mesophases through nanosegregation of the ionic and non‐ionic parts. Considering the intrinsic characteristic of ‐type bicontinuous cubic structures that they are composed of intertwined right‐ and left‐handed single gyroids, we propose that the simultaneous presence of both R‐ and S‐atropisomers is an important contributor to the formation of double‐gyroid structures. 相似文献
12.
Dr. Wen-Long Huang Dr. Xu-Dong Wang Dr. Yu-Fei Ao Prof. Dr. Qi-Qiang Wang Prof. Dr. De-Xian Wang 《Angewandte Chemie (International ed. in English)》2023,62(23):e202302198
Inspired by the unique structure and function of the natural chloride channel (ClC) selectivity filter, we present herein the design of a ClC-type single channel molecule. This channel displays high ion transport activity with half-maximal effective concentration, EC50, of 0.10 μM, or 0.075 mol % (channel molecule to lipid ratio), as determined by fluorescent analysis using lucigenin-encapsulated vesicles. Planar bilayer lipid membrane conductance measurements indicated an excellent Cl−/K+ selectivity with a permeability ratio P /P up to 12.31, which is comparable with the chloride selectivity of natural ClC proteins. Moreover, high anion/anion selectivity (P /P =66.21) and pH-dependent conductance and ion selectivity of the channel molecule were revealed. The ClC-like transport behavior is contributed by the cooperation of hydrogen bonding and anion–π interactions in the central macrocyclic skeleton, and by the existence of pH-responsive terminal phenylalanine residues. 相似文献
13.
Lun Jin Michael Lane Dihao Zeng Franziska K. K. Kirschner Dr. Franz Lang Dr. Pascal Manuel Prof. Stephen J. Blundell Prof. John E. McGrady Prof. Michael A. Hayward 《Angewandte Chemie (International ed. in English)》2018,57(18):5025-5028
The synthesis of the first 4d transition metal oxide–hydride, LaSr3NiRuO4H4, is prepared via topochemical anion exchange. Neutron diffraction data show that the hydride ions occupy the equatorial anion sites in the host lattice and as a result the Ru and Ni cations are located in a plane containing only hydride ligands, a unique structural feature with obvious parallels to the CuO2 sheets present in the superconducting cuprates. DFT calculations confirm the presence of S= Ni+ and S=0, Ru2+ centers, but neutron diffraction and μSR data show no evidence for long‐range magnetic order between the Ni centers down to 1.8 K. The observed weak inter‐cation magnetic coupling can be attributed to poor overlap between Ni 3d and H 1s in the super‐exchange pathways. 相似文献
14.
The β‐Agostic Structure in (C5Me5)2Sc(CH2CH3): Solid‐State NMR Studies of (C5Me5)2Sc−R (R=Me,Ph, Et)
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Damien B. Culver Winn Huynh Dr. Hosein Tafazolian Dr. Ta‐Chung Ong Prof. Dr. Matthew P. Conley 《Angewandte Chemie (International ed. in English)》2018,57(30):9520-9523
Multinuclear solid‐state NMR studies of Cp*2Sc?R (Cp*=pentamethylcyclopentadienyl; R=Me, Ph, Et) and DFT calculations show that the Sc?Et complex contains a β‐CH agostic interaction. The static central transition 45Sc NMR spectra show that the quadrupolar coupling constants (Cq) follow the trend of Ph≈Me>Et, indicating that the Sc?R bond is different in Cp*2Sc?Et compared to the methyl and phenyl complexes. Analysis of the chemical shift tensor (CST) shows that the deshielding experienced by Cβ in Sc?CH2CH3 is related to coupling between the filled σC‐C orbital and the vacant orbital. 相似文献
15.
Dr. Fabian Hecker Lisa Fries Dr. Markus Hiller Prof. Dr. Mario Chiesa Prof. Dr. Marina Bennati 《Angewandte Chemie (International ed. in English)》2023,62(4):e202213700
The hydration structure of nitroxide radicals in aqueous solutions is elucidated by advanced 17O hyperfine (hf) spectroscopy with support of quantum chemical calculations and MD simulations. A piperidine and a pyrrolidine-based nitroxide radical are compared and show clear differences in the preferred directionality of H-bond formation. We demonstrate that these scenarios are best represented in 17O hf spectra, where in-plane coordination over -type H-bonding leads to little spin density transfer on the water oxygen and small hf couplings, whereas -type perpendicular coordination generates much larger hf couplings. Quantitative analysis of the spectra based on MD simulations and DFT predicted hf parameters is consistent with a distribution of close solvating water molecules, in which directionality is influenced by subtle steric effects of the ring and the methyl group substituents. 相似文献
16.
17.
Sandip Chattopadhayay Anupam Ghosh Dr. Titas Kumar Mukhopadhyay Rashmi Sharma Prof. Ayan Datta Prof. Pinaki Talukdar 《Angewandte Chemie (International ed. in English)》2023,62(46):e202313712
The structural tropology and functions of natural cation-anion symporting channels have been continuously investigated due to their crucial role in regulating various physiological functions. To understand the physiological functions of the natural symporter channels, it is vital to develop small-molecule-based biomimicking systems that can provide mechanistic insights into the ion-binding sites and the ion-translocation pathways. Herein, we report a series of bis((R)-(−)-mandelic acid)-linked 3,5-diaminobenzoic acid based self-assembled ion channels with distinctive ion transport ability. Ion transport experiment across the lipid bilayer membrane revealed that compound 1 b exhibits the highest transport activity among the series, and it has interesting selective co-transporting functions, i.e., facilitates K+/ClO4− symport. Electrophysiology experiments confirmed the formation of supramolecular ion channels with an average diameter of 6.2±1 Å and single channel conductance of 57.3±1.9 pS. Selectivity studies of channel 1 b in a bilayer lipid membrane demonstrated a permeability ratio of , , and indicating the higher selectivity of the channel towards KClO4 over KCl salt. A hexameric assembly of a trimeric rosette of 1 b was subjected to molecular dynamics simulations with different salts to understand the supramolecular channel formation and ion selectivity pattern. 相似文献
18.
Yan Zhang Margaret A. Hopkins David J. Liptrot Hamideh Khanbareh Pim Groen Xuefan Zhou Dou Zhang Yinxiang Bao Kechao Zhou Chris R. Bowen David R. Carbery 《Angewandte Chemie (International ed. in English)》2020,59(20):7808-7812
We demonstrate that trimethylamine borane can exhibit desirable piezoelectric and pyroelectric properties. The material was shown to be able operate as a flexible film for both thermal sensing, thermal energy conversion and mechanical sensing with high open circuit voltages (>10 V). A piezoelectric coefficient of d33≈10–16 pC N?1, and pyroelectric coefficient of p≈25.8 μC m?2 K?1 were achieved after poling, with high pyroelectric figure of merits for sensing and harvesting, along with a relative permittivity of 6.3. 相似文献
19.
David Zanders Goran Ba
i Dominique Leckie Oluwadamilola Odegbesan Jeremy Rawson Jason D. Masuda Anjana Devi Sen T. Barry 《Angewandte Chemie (International ed. in English)》2020,59(33):14138-14142
Attempted preparation of a chelated CoII β‐silylamide resulted in the unprecedented disproportionation to Co0 and a spirocyclic cobalt(IV) bis(β‐silyldiamide): [Co[(NtBu)2SiMe2]2] ( 1 ). Compound 1 exhibited a room‐temperature magnetic moment of 1.8 B.M. and a solid‐state axial EPR spectrum diagnostic of a rare S= configuration for tetrahedral CoIV. Ab initio semicanonical coupled‐cluster calculations (DLPNO‐CCSD(T)) revealed the doublet state was clearly preferred (?27 kcal mol?1) over higher spin configurations only for the bulky tert‐butyl‐substituted analogue. Unlike other CoIV complexes, 1 had remarkable thermal stability, and was demonstrated to form a stable self‐limiting monolayer in preliminary atomic layer deposition (ALD) surface saturation experiments. The ease of synthesis and high stability make 1 an attractive starting point to investigate otherwise inaccessible CoIV intermediates and for synthesizing new materials. 相似文献
20.
Indrek Kalvet Guillaume Magnin Prof. Dr. Franziska Schoenebeck 《Angewandte Chemie (International ed. in English)》2017,56(6):1581-1585
While chemoselectivities in Pd0‐catalyzed coupling reactions are frequently non‐intuitive and a result of a complex interplay of ligand/catalyst, substrate, and reaction conditions, we herein report a general method based on PdI that allows for an a priori predictable chemoselective C −C coupling at C−Br in preference to C−OTf and C−Cl bonds, regardless of the electronic or steric bias of the substrate. The C−C bond formations are extremely rapid (<5 min at RT) and are catalyzed by an air‐ and moisture‐stable PdI dimer under open‐flask conditions. 相似文献