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101.
Maite Nößler René Jäger David Hunger Dr. Marc Reimann Tobias Bens Dr. Nicolás I. Neuman Dr. Arijit Singha Hazari Prof. Dr. Martin Kaupp Prof. Dr. Joris van Slageren Prof. Dr. Biprajit Sarkar 《欧洲无机化学杂志》2023,26(19):e202300091
Due to their ability to form stable molecular complexes that have tailor-made properties, terpyridine ligands are of great interest in chemistry and material science. In this regard, we prepared two terpyridine ligands with two different fluorinated phenyl rings on the backbone. The corresponding CoII and FeII complexes were synthesized and characterized by single-crystal X-ray structural analysis, electrochemistry and temperature-dependent SQUID magnetometry. Single crystal X-ray diffraction analyses at 100 K of these complexes revealed Co−N and Fe−N bond lengths that are typical of low spin CoII and FeII centers. The metal centers are coordinated in an octahedral fashion and the fluorinated phenyl rings on the backbone are twisted out of the plane of the terpyridine unit. The complexes were investigated with cyclic voltammetry and UV/Vis-NIR spectroelectrochemistry. All complexes show a reversible oxidation and several reduction processes. Temperature dependent SQUID magnetometry revealed a gradual thermal SCO behavior in two of the complexes, while EPR spectroscopy provided further insights on the electronic structure of the metal complexes, as well as site of reduction. 相似文献
102.
Chengzhi Chen Tingting Yuan Prof. Ping Lan Prof. Lorenzo V. White Prof. Jing Chen Prof. Dr. Martin G. Banwell 《European journal of organic chemistry》2023,26(16):e202300003
Total syntheses of the title marine natural products have been achieved and so confirming the structures originally assigned to them. Upon subjecting agesasine A and its corresponding ethyl ester to Mitsunobu conditions, a 1,5-cyclodehydration reaction takes place to give 2-oxazolines. In contrast, on subjecting agesasine B to the same Mitsunobu conditions, a simple dehydration reaction occurs to give the corresponding acrylate. A total synthesis of longamide E was achieved by engaging a 1,2-disubstituted pyrrole in a lactam-forming reaction and this was followed by a two-fold and fully regio-controlled bromination reaction. A distinctly different and possibly biomimetic route was used to synthesize, via the open-chain natural product nakamurine B, longamide B and its methyl ester. Preliminary biological evaluations of the title alkaloids and various analogues against a small human cancer cell line panel reveals cytotoxic properties that vary significantly with structure. 相似文献
103.
Dr. Martin Kamlar Dr. Ivana Císařová Prof. Jan Veselý 《European journal of organic chemistry》2023,26(32):e202300400
We report a Brønsted acid-catalyzed synthesis of tetrasubstituted allenyl compounds decorated with heterocyclic sulfenyl group. The reaction proceeds readily from available propargylic alcohols in the presence of pentacarboxycyclopenatadienes (PCCPs) as organocatalysts. The developed strategy provides tetrasubstituted allene derivatives in high yields (from 55 to 98 %) and under mild reaction conditions. 相似文献
104.
Peptides and proteins are exposed to a variety of interfaces in a physiological environment, such as cell membranes, protein nanoparticles (NPs), or viruses. These interfaces have a significant impact on the interaction, self-assembly, and aggregation mechanisms of biomolecular systems. Peptide self-assembly, particularly amyloid fibril formation, is associated with a wide range of functions; however, there is a link with neurodegenerative diseases, such as Alzheimer's disease. This review highlights how interfaces affect peptide structure and the kinetics of aggregation leading to fibril formation. In nature, many surfaces are nanostructures, such as liposomes, viruses, or synthetic NPs. Once exposed to a biological medium, nanostructures are coated with a corona, which then determines their activity. Both accelerating and inhibiting effects on peptide self-assembly have been observed. When amyloid peptides adsorb to a surface, they typically concentrate locally, which promotes aggregation into insoluble fibrils. Starting from a combined experimental and theoretical approach, models that allow for a better understanding of peptide self-assembly near hard and soft matter interfaces are introduced and reviewed. Research results from recent years are presented and relationships between biological interfaces, such as membranes and viruses, and amyloid fibril formation are proposed. 相似文献
105.
James P. C. Coverdale Dr. Carlos Sanchez‐Cano Dr. Guy J. Clarkson Dr. Rina Soni Prof. Dr. Martin Wills Prof. Dr. Peter J. Sadler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8043-8046
Asymmetric transfer hydrogenation (ATH) is an important process in organic synthesis for which the Noyori‐type RuII catalysts [(arene)Ru(Tsdiamine)] are now well established and widely used. We now demonstrate for the first time the catalytic activity of the osmium analogues. X‐ray crystal structures of the 16‐electron OsII catalysts are almost identical to those of RuII. Intriguingly the precursor complex was isolated as a dichlorido complex with a monodentate amine ligand. The OsII catalysts are readily synthesised (within 1 h) and exhibit excellent enantioselectivity in ATH reactions of ketones. 相似文献
106.
Per Martin Björemark Dr. Susanne Olsson Dr. Theonitsa Kokoli Prof. Mikael Håkansson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(24):8750-8753
Even though the isolation of tetrahedral stereoisomers usually presents a synthetic challenge, a highly enantioenriched tetrahedral silver complex could be easily accessed by either crystallization or Viedma ripening. The overall preparation may be regarded as an example of absolute asymmetric synthesis. Experimental results indicate that both crystallization and Viedma ripening follow a similar cluster‐controlled mechanism. 相似文献
107.
Asymmetric Catalysis with Silicon‐Based Cuprates: Enantio‐ and Regioselective Allylic Substitution of Linear Precursors 下载免费PDF全文
Alexander Hensel Prof. Dr. Martin Oestreich 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(25):9062-9065
An enantio‐ and regioselective allylic silylation of linear allylic phosphates that makes use of catalytically generated cuprate‐type silicon nucleophiles is reported. The method relies on soft bis(triorganosilyl) zincs as silicon pronucleophiles that are prepared in situ from the corresponding hard lithium reagents by transmetalation with ZnCl2. With a preformed chiral N‐heterocyclic carbene–copper(I) complex as catalyst, exceedingly high enantiomeric excesses are achieved. The new method is superior to existing ones using a silicon–boron reagent as the source of the silicon nucleophile. 相似文献
108.
Rory Campbell Dr. Martin F. Davis Mathew Fazakerley Dr. Peter Portius 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(51):18690-18698
The first charge‐neutral Lewis base adducts of tin(IV) tetraazide, [Sn(N3)4(bpy)], [Sn(N3)4(phen)] and [Sn(N3)4(py)2], and the salt bis{bis(triphenylphosphine)iminium} hexa(azido)stannate [(PPN)2Sn(N3)6] (bpy = 2,2′‐bipyridine; phen = 1,10‐phenanthroline; py = pyridine; PPN = N(PPh3)2) have been prepared using covalent or ionic azide‐transfer reagents and ligand‐exchange reactions. The azides were isolated on the 0.3 to 1 g scale and characterized by IR and NMR spectroscopies, microanalytical and thermal methods and their molecular structures determined by single‐crystal XRD. All complexes have a distorted octahedral Sn[N]6 coordination geometry and possess greater thermal stability than their Si and Ge homologues. The nitrogen content of the adducts of up to 44 % exceed any SnIV compound known hitherto. 相似文献
109.
110.
Frontispiece: Hydrogenated Graphenes by Birch Reduction: Influence of Electron and Proton Sources on Hydrogenation Efficiency,Magnetism, and Electrochemistry 下载免费PDF全文