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2,132 results on '"Villinger, Alexander"'

151. Facile Synthesis of a Stable Side-on Phosphinyne Complex by Redox Driven Intramolecular Cyclisation

Author

Lange, Helge, Schr��der, Henning, Oberem, Elisabeth, Villinger, Alexander, Rabeah, Jabor, Ludwig, Ralf, Neymeyr, Klaus, and Seidel, Wolfram W.

Subjects
cyclisation mechanism, phosphinyne complex, frustrated Lewis pair, non-innocent ligand, alkyne complex
Abstract

Alkyne complexes with vicinal substitution by a Lewis acid and a Lewis base at the coordinated alkyne are prospective frustrated Lewis pairs exhibiting a particular mutual distance and, hence, a specific activation potential. In this contribution, investigations on the generation of a WII alkyne complex bearing a phosphine as Lewis base and a carbenium group as Lewis acid are presented. Independently on potential substrates added, an intramolecular cyclisation product was always isolated. A subsequent deprotonation step led to an unprecedented side-on ��5-phosphinyne complex, which is interpreted as highly zwitterionic according to visible absorption spectroscopy supported by TD-DFT. Low-temperature 31P NMR and EPR spectroscopic measurements combined with time-dependent IR-spectroscopic monitoring provided insights in the mechanism of the cyclisation reaction. Decomposition of the multicomponent IR spectra by multivariate curve resolution and a kinetic hard-modelling approach allowed the derivation of kinetic parameters. Assignment of the individual IR spectra to potential intermediates was provided by DFT calculations. �� 2020 The Authors. Published by Wiley-VCH GmbH

Published
2020
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159. Metal/Metal Redox Isomerism Governed by Configuration

Author

Ludwig, Stephan, primary, Helmdach, Kai, additional, Hüttenschmidt, Mareike, additional, Oberem, Elisabeth, additional, Rabeah, Jabor, additional, Villinger, Alexander, additional, Ludwig, Ralf, additional, and Seidel, Wolfram W., additional

Published
2020
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161. Mono-, di-, and tricoordinated attached to a N-N unit: An experimental and theoretical study

Author

Fischer, Gerd, Mayer, Peter, Schulz, Axel, Villinger, Alexander, Weigand, Jan J., and Herler, Sebastian

Subjects
Methyl groups -- Chemical properties, Methyl groups -- Structure, Phosphonates -- Chemical properties, Phosphonates -- Structure, Chemistry
Abstract

N,N',N'-[Tris(trimethylysilyl)]hydrazino-diphenylphosphane, (TMS)2N-(TMS)N-PPh2, and N,N',N'-[tris(trismethylsilyl]hydrazino-phenyl(chloro)phosphane, (TMS)2N-(TMS)N-P(Cl)Ph2, are obtained in the reaction of bis-[lithium-tris(trimethylsilyl)hydrazide] with Ph(sub n)PCl(sub 3-n) (n = 1,2). The structure and bonding of both species are discussed on the basis of experimentally observed and theoretically obtained data.

Published
2005

186. A Phosphorus‐Based Pacman Dication Generated by Cooperative Self‐Activation of a Pacman Phosphane.

Author

Eickhoff, Liesa, Ohms, Leon, Bresien, Jonas, Villinger, Alexander, Michalik, Dirk, and Schulz, Axel

Subjects
SCHIFF bases, DOUBLE bonds, PYRROLES, OXIDATION-reduction reaction, MACROCYCLIC compounds
Abstract

Formal coordination of phosphorus(III) by a calix[4]pyrrole Schiff base ligand was achieved through the reaction of this ligand with PCl3 under basic conditions. The reaction product adopts a Pacman conformation with two P−Cl moieties, one in exo and one in endo position. It represents the first non‐metal compound of calix[4]pyrrole Schiff base ligands and of Pacman ligands in general. The spatial neighborhood of the two phosphorus atoms enables cooperative reactions. As a first example, the chloride abstraction with AgOTf is presented, yielding a macrocyclic dication with two embedded phosphorus(III) monocations, which both undergo a cooperative, internal activation reaction with an adjacent C=N double bond. This intramolecular redox process affords two pentacoordinated phosphorus(V) centers within the Pacman dication. All reaction products were fully characterized and all results are supported by computations. [ABSTRACT FROM AUTHOR]

Published
2022
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187. (R)-Baclofen [(R)-4-amino-3-(4-chlorophenyl)-butanoic acid].

Author

Belov, Feodor, Villinger, Alexander, and von Langermann, Jan

Subjects
*CRYSTAL structure, *SPACE groups, *ACIDS, *HYDROGEN bonding
Abstract

This article provides the first single-crystal XRD-based structure of enantiopure (R)-baclofen (form C), C10H12ClNO2, without any co-crystallized substances. In the enantiopure title compound, the molecules arrange themselves in an orthorhombic crystal structure (space group P212121). In the crystal, strong hydrogen bonds and C--H...Cl bonds interconnect the zwitterionic molecules. [ABSTRACT FROM AUTHOR]

Published
2022
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188. Reaction of potassium phosphide KP(iPr)Ter with chalcogens, heteroallenes and an acyl chloride.

Author

Szych, Lilian Sophie, Lüdtke, Karsten Paul, Pilopp, Yannic, Bresien, Jonas, Villinger, Alexander, and Schulz, Axel

Subjects
ACYL chlorides, SMALL molecules, POTASSIUM, CHALCOGENS
Abstract

The reactivity of the secondary phosphide KP(iPr)Ter (1) (Ter = 2,6-bis-(2,4,6-trimethylphenyl)phenyl) toward small molecules is reported. Phosphide 1 displays distinct nucleophilic character and reacts selectively with chalcogens (S8, Sex), heteroallenes (CO2, nPrNCS), and an acyl chloride (AdCOCl) to give the corresponding dichalcogenophosphinates (2a, 3), phosphanyl formate (5), thiocarbamoylphosphane (6a), or acylphosphane (7a), respectively. Furthermore the follow-up chemistry of these products was investigated. 2a was converted to a PSPS ligand (2b) which forms a Au(I) complex (2c) with (Me2S)AuCl. Likewise, a gold complex of 7a was prepared. All species were isolated and fully characterized. [ABSTRACT FROM AUTHOR]

Published
2021
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189. Silylated Sulfuric Acid: Preparation of a Tris(trimethylsilyl)oxosulfonium [(Me3Si−O)3SO]+ Salt.

Author

Bläsing, Kevin, Labbow, Rene, Schulz, Axel, and Villinger, Alexander

Subjects
SULFURIC acid, SALT, SALTS, SILYLATION, SULFATES, LEWIS acids
Abstract

The chemistry of silylated sulfuric acid, O2S(OSiMe3)2 (T2SO4, T=Me3Si; also known as bis(trimethylsilyl) sulfate), has been studied in detail with the aim of synthesizing the formal autosilylation products of silylated sulfuric acid, [T3SO4]+ and [TSO4]−, in analogy to the known protonated species, [H3SO4]+ and [HSO4]−. The synthesis of the [TSO4]− ion only succeeds when a base, such as OPMe3 that forms a weakly coordinating cation upon silylation, is reacted with T2SO4, resulting in the formation of [Me3POT]+[TSO4]−. [T3SO4]+ salts could be isolated starting from T2SO4 in the reaction with [T−H−T]+[B(C6F5)4]− or T+[CHB11Br6H5]− when a weakly coordinating anion is used as counterion. All silylated compounds could be crystallized and structurally characterized. [ABSTRACT FROM AUTHOR]

Published
2021
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190. Trimethylsilyl Pseudohalide Adducts of GaCl3 and B(C6F5)3.

Author

Bläsing, Kevin, Bresien, Jonas, Maurer, Steffen, Schulz, Axel, and Villinger, Alexander

Subjects
LEWIS acids, CHARGE transfer, CRYSTAL structure, SINGLE crystals, THERMODYNAMICS
Abstract

Me3Si−X (X=CN, N3, OCN, and SCN) was treated with the Lewis acids GaCl3 and B(C6F5)3 in toluene yielding the desired adducts Me3Si−X→GaCl3 and Me3Si−X→B(C6F5)3. All synthesized adducts were isolated and completely characterized including single crystal structure elucidations. The different structures, thermodynamics of formation and charge transfer effects are discussed on the basis of experimental and theoretical data. [ABSTRACT FROM AUTHOR]

Published
2021
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