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Angewandte Chemie

Cody Ross Pitts, Dustin Bornemann, Phil Liebing, Nico Santschi, Antonio Togni
Modern pentafluorosulfanyl (SF5) chemistry has an Achilles heel: synthetic accessibility. Herein, we present the first approach to aryl-SF4Cl compounds (key intermediates in state-of-the-art aryl-SF5 synthesis) that overcomes the reliance on hazardous fluorinating reagents and/or gas reagents (e.g. Cl2) by employing easy-to-handle trichloroisocyanuric acid, potassium fluoride, and catalytic acid. These simple, mild conditions allow direct access to aryl-SF4Cl intermediates that have not been or cannot be demonstrated using previous methods...
November 14, 2018: Angewandte Chemie
Tobias Morack, Christian Mück-Lichtenfeld, Ryan Gilmour
A bioinspired, intermolecular radical Stetter reaction of α-keto acids and aldehydes is disclosed that is contingent on a formal "radical-Umpolung" concept. Enabled by secondary amine activation, electrostatic recognition ensures that the α-ketocarboxylic acids, which function as latent acyl radicals, are proximal to the in-situ generated iminium salts. This photoactive contact ion-pair is an electron-donor-acceptor (EDA) complex, which undergoes facile single electron transfer (SET) and rapid decarboxylation prior to radical-radical recombination...
November 14, 2018: Angewandte Chemie
Martin Srnec, Rafael Navrátil, Erik Andris, Juraj Jašík, Jana Roithová
The CuO+ core is a central motif of reactive intermediates in copper-catalysed oxidations occurring in Nature. The high reactivity of CuO+ stems from a weak bonding between the atoms, which cannot be described by a simple classical model. To obtain the correct picture, we have investigated acetonitrile-ligated CuO+ ion using neon tagging photodissociation spectroscopy at 3K. The spectra feature complex vibronic absorption progressions in both near-infrared and visible regions. Employing Frank-Condon analyses, we derived from the experiment the low-lying triplet potential energy surfaces that were further correlated with multireference calculations...
November 14, 2018: Angewandte Chemie
Karsten Meyer, Christopher J Hoerger, Frank W Heinemann, Elisa Louyriac, Massimo Rigo, Laurent Maron, Hansjörg Grützmacher, Matthias Driess
Reaction of the trivalent uranium complex [((Ad,MeArO)3N)-U(DME)] with one molar equivalent [Na(OCAs)(dioxane)3], in the presence of 2.2.2-crypt, yields [Na(2.2.2-crypt)]-[{((Ad,MeArO)3N)-UIV(THF)}-(μ-O)-{((Ad,MeArO)3N)-UIV(CAs)}] (1), which is the arsenic containing analogue of the previously reported, μ-oxo-bridged di-uranium cyaphide complex. The structural characterization of complex 1 reveals the first example of a coordinated η1-cyaarside ligand (CAs-). The terminal CAs- anionic ligand formation is promoted by the highly reducing, oxo-philic uranium(III) precursor [((Ad,MeArO)3N)-U(DME)] and proceeds through reductive C-O bond cleavage of the bound arsaethynolate anion, OCAs-...
November 14, 2018: Angewandte Chemie
Bin Zhao, Sheng-Li Hou, Jie Dong, Xiao-Lei Jiang, Zhuo-Hao Jiao
Cyclization of propargylic alcohols with CO2 is an important reaction in industry, and noble metal catalysts are often employed to ensure the high product yields under environmentally friendly conditions. Herein a porous noble-metal-free framework {(NH2C2H6)0.75[Cu4I4·(L)3·(In)0.75]·DMF·H2O} (1) with large 1D channels of 1.66 nm diameter was rationally synthesized for this reaction. Compound 1 exhibits excellent acid/base stability, and even can keep stable in corrosive triethylamine for one month. Catalytic explorations indicate that 1 can sever as an effective catalyst for carboxylative cyclization of propargylic alcohols and CO2 without any solvents under mild conditions, and the turnover number (TON) can reach to a record value of 14400...
November 14, 2018: Angewandte Chemie
Theresa Fischer, Julia Bamberger, Melania Gómez-Martínez, Dariusz Piekarski, Olga García Mancheño
A general and highly enantioselective synthesis of oxygen heterocycles from readily available in situ generated pyrylium derivatives has been realized by embracing a multi-coordination triazole-based anion-binding catalysis approach. The high activity of the helical tetrakistriazole catalysts (TetraTri), with distinct confined anion-binding pockets, allows remarkably low catalytic loadings (down to 0.05 mol%), while providing a simple access to chiral chromanones and dihydropyrones in high enantioselectivities (up to 98:2 e...
November 14, 2018: Angewandte Chemie
Jan Rinkel, Lukas Lauterbach, Jeroen Sidney Dickschat
A diterpene synthase from Saccharopolyspora spinosa was found to convert geranylgeranyl diphosphate into the new natural products spinodiene A and B, accompanied by 2,7,18-dolabellatriene. The structures and the formation mechanism of the enzyme products were investigated by extensive isotopic labelling experiments, revealing an unusual branched isomerisation mechanism towards the neutral intermediate 2,7,18-dolabellatriene. A Diels-Alder approach was used to convert the main diterpene product with its rare conjugated diene moiety into formal sesterterpene alcohols...
November 14, 2018: Angewandte Chemie
Hejin Jiang, Yuqian Jiang, Jianlei Han, Li Zhang, Minghua Liu
While chiral nanostructures are interesting, it remains a big challenge to control the hierarchical chirality transfer from molecule to the higher order structures and their switching. Here, photo-sensitive cinnamic acid conjugated glutamides (L/D-CG) were designed to demonstrate the photo-controlled hierarchical chirality transfer and switching in self-assembly system. The cinnamic acid derivative self-assembled into superhelix in methanol, which could be switched into nanokebab upon UV irradiation. These two nanostructures showed opposite helicity...
November 13, 2018: Angewandte Chemie
Huijun Yang, Cheng Guo, Jiahang Chen, Ahmad Naveed, Jun Yang, Yanna Nuli, Jiulin Wang
Safety concern poses a significant challenge for the large-scale employment of lithium-sulfur batteries. Extreme flammable conventional electrolyte and dendritic lithium deposition cause severe safety issues. Herein, we report an intrinsic flame-retardant (IFR) electrolyte consisting of 1.1 M lithium bis(fluorosulfonyl)imide in a solvent mixture of flame-retardant triethyl phosphate and high flash point solvent 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl (1:3, v/v) for safe lithium-sulfur (Li-S) batteries...
November 13, 2018: Angewandte Chemie
Yinqiang Xia, Vahid Adibnia, Renliang Huang, Frederic Murschel, Jimmy Faivre, Guojun Xie, Mateusz Olszewski, Gregory De Crescenzo, Wei Qi, Zhimin He, Rongxin Su, Krzysztof Matyjaszewski, Xavier Banquy
The increasing demand for long lasting antifouling surfaces has steered the development of accessible, novel, biocompatible and environmentally-friendly materials. Inspired by lubricin (LUB), a component of mammalian synovial fluid with excellent antifouling properties, we designed three block polymers with bottle-brush structures and outstanding stability, efficacy, and ease of use. By a simple drop casting or online exposure, the polymers strongly adsorbed on silica surfaces in less than 10 min and were found to be stable in extremely high-salinity solutions and under an unprecedented wide range of pH...
November 13, 2018: Angewandte Chemie
Frieder Jäkle, Fernando Vidal
The past decade has witnessed tremendous advances in the synthesis of polymers that contain elements from the Main Groups beyond those found in typical organic polymers. Unique properties that arise from dramatic differences in bonding and molecular geometry, electronic structure, and chemical reactivity, are exploited in diverse application fields. In here we highlight recent advances in inorganic backbone polymers, discuss how Lewis acid/base functionalization of polymers results in unprecedented reactivity, and survey conjugated hybrids with unique electronic structures for sensor and device applications...
November 13, 2018: Angewandte Chemie
Chuan-Zhi Liu, Satish Koppireddi, Hui Wang, Dan-Wei Zhang, Zhan-Ting Li
Halogen bonding has been used to glue hydrogen bonded short arylamide foldamers to achieve new supramolecular double and quadruple helices in the solid state. Compounds 1-3, which bear one pyridine at one end and one CF2I or fluorinated iodobenzene group at the other end, are induced by head-to-tail N⋅⋅⋅I halogen bonding to form one-component supramolecular P and M helices, which further stack to afford supramolecular double-stranded helices. Double helix formed by 3 can further dimerize to form a G-quadruplex-like supramolecular quadruple helix...
November 13, 2018: Angewandte Chemie
Chuangwei Jiao, Zumin Wang, Xiaoxian Zhao, Huan Wang, Jing Wang, Ranbo Yu, Dan Wang
Precisely carving of multi-shelled manganese-cobalt oxide hollow dodecahedra (Co/Mn-HD) with shell number up to three has been achieved by using a controlled calcination of the Mn doped ZIF-67 precursor (Co/Mn-ZIF). The unique multi-shelled and polycrystalline structure not only provides very large electrochemically active surface area (EASA), but also enhances the structural stability of the material. The residual C and N in the final multi-shelled structures might benefit the shell structure stability of Co/Mn-HD, and increase their conductivity as well...
November 13, 2018: Angewandte Chemie
Omar M Yaghi, Kyle E Cordova
We detail the lessons learned, challenges, achievements, and outlook in building a chemistry research center in Vietnam. Through the principles of 'global science', we provide specific insight into the process behind establishing an internationally-competitive research program - a model that is scalable and adaptable to countries beyond Vietnam. Furthermore, we highlight the prospects for success in advancing global science education, research capacity building, and mentorship.
November 13, 2018: Angewandte Chemie
Xiong-Wen David Lou
We demonstrate the delicate design and synthesis of hierarchical microboxes assembled from SnS nanoplates coated with nitrogen-doped carbon (NC) as an anode material for sodium-ion batteries. The template-engaged multistep synthesis of the SnS@NC microboxes involves sequential phase transformation, polydopamine coating, and thermal annealing in N2. The SnS@NC composite with two-dimensional nanosized subunits rationally integrates several advantages including shortening the diffusion path of electrons/Na+ ions, improving electric conductivity and alleviating volume variation of the electrode material...
November 13, 2018: Angewandte Chemie
Jeremy Michael Rawson, Mitchell A Nascimento, Elodie Heyer, Joshua J Clarke, Hugh J Cowley, Antonio Alberola, Nadia Stephaniuk
Formation of radical-radical cocrystals is an important step towards the design of organic ferrimagnets. We describe a simple approach to generate radical-radical cocrystals through the identification and implementation of well-defined supramolecular synthons which favor cocrystallization over phase separation. In the current paper we implement the structure-directing interactions of the E-E bond (E = S, Se) of dithiadiazolyl (DTDA) and diselenadiazolyl (DSDA) radicals to form close contacts to electronegative groups...
November 13, 2018: Angewandte Chemie
Marie-Laure Bocquet, Nicolas Lorente, Richard Berndt, Manuel Gruber
Depositing intact organic radicals on various substrates can be challenging. Generally, inert metal surfaces present more chances of hosting the intact radicals, but the large amounts of delocalized electronic states favor charge transfer and ultimately spin quenching. Reducing the molecule-substrate interaction is a usual strategy to stabilize radicals on surfaces. To this end, thin insulating layers have been introduced to provide a controllable degree of electronic decoupling. Recently, retinoid molecules adsorbed on gold have been manipulated with a scanning tunneling microscope (STM) to exhibit a localized spin...
November 13, 2018: Angewandte Chemie
Thibault Fogeron, Pascal Retailleau, Lise-Marie Chamoreau, Yun Li, Marc Fontecave
Two original dithiolenes, with a pyrazine ring fused with a pyran ring carrying the dithiolene chelate, mimicking molybdopterin (MPT) present in the active site of formate dehydrogenases (FDHs), have been synthesized. The first one mimicks MPT in the dihydropyrazine form while the second mimicks MPT in the more biologically relevant tetrahydropyrazine form. Both have been structurally characterized as a ligand within a Co(cyclopentadienyl)(dithiolene) complex. The corresponding MoO(dithiolene)2 complexes have been also prepared and are reported as the first functional and stable catalysts inspired by the Mo center of FDHs so far: they indeed catalyze the photoreduction of CO2 into formic acid, as the major product, and carbon monoxide, achieving more than 100 turnover numbers in about 8 h...
November 13, 2018: Angewandte Chemie
Sjoerd Harder, Thomas Xaver Gentner, Bastian Rösch, Gerd Ballmann, Jens Langer, Holger Elsen
The steric bulk of the well-known DIPPBDI ligand (CH[C(CH3)N-Dipp]2, DIPP =2,6-diisopropylphenyl) was increased by replacing isopropyl for isopentyl groups. This very bulky DIPePBDI ligand could not stabilize the radical species (DIPePBDI)Mg•: reduction of (DIPePBDI)MgI with Na gave (DIPePBDI)2Mg2 with a rather long Mg-Mg bond of 3.0513(8) Å. Addition of TMEDA prior to reduction gave mplex (DIPePBDI)2Mg2(C6H6) which could also be obtained as its THF adduct. It is speculated that combination of a bulky spectator ligand and TMEDA prevents dimerization of the intermediate Mg(I) radical which then reacts with the benzene solvent...
November 13, 2018: Angewandte Chemie
Lei Peng, Da Xu, Xiaohong Yang, Jiakun Tang, Xuli Feng, Shao-Lin Zhang, Hailong Yan
An organocatalytic one-step desymmetrizing dearomatization reaction of indoles with in situ formed vinylidene ortho-quinone methide (VQM) is reported. A set of [6-6-5] and/or [5-6-5] fused indoline heterocycles were obtained in excellent yields with excellent diastereoselectivities (>20:1 dr) and enantioselectivities (up to 99% ee). Moreover, some of the obtained products were screened against a panel of cancer cell lines, and 2s was identified to inhibit the proliferation of all the tested cancer cells, but showed the marginal effect against non-cancerous cells...
November 13, 2018: Angewandte Chemie
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