[Uni Tübingen] - [Mat.-Nat. Fakultät] - [Fachbereich Chemie] - [Anorg. Chemie] - [Klaus Eichele] - [Publications] - Abstracts 2015

Klaus Eichele Publication Abstracts 2015


[UP] K. M. Krebs, J. Wiederkehr, J. Schneider, K. Eichele, H. Schubert, L. Wesemann:
η3-Allylkoordination an Zinn(II) – Reaktivität gegenüber Alkinen und Benzonitril
Angew. Chem. 2015, 127 5593-5597.
DOI: 10.1002/ange.201500386

Wir berichten über die Synthese und Charakterisierung eines Allyl-SnII-Komplexes, der eine η3-Koordination in Lösung und im Festkörper aufweist. Zwei Beispiele für die Reaktivität des Allylderivates werden vorgestellt: Die Reaktion mit terminalen Alkinen ergibt tricyclische Verbindungen, während die Umsetzung mit Benzonitril über eine C-H-Aktivierung zu einem 16 Atome umfassenden Ringsystem führt.


[UP] K. M. Krebs, J. Wiederkehr, J. Schneider, K. Eichele, H. Schubert, L. Wesemann:
η3-Allyl Coordination at Tin(II) – Reactivity towards Alkynes and Benzonitrile
Angew. Chem. Int. Ed. 2015, 54, 5502-5506.
DOI: 10.1002/anie.201500386

We herein report the synthesis and characterization of a terphenyl-substituted SnII allyl compound featuring an η3 coordination mode in solution and in the solid state. Two examples for the interesting reactivity of the allyl SnII molecule are presented: Reactions with terminal alkynes result in the formation of tricyclic compounds by C-C bond formation and the dimerization of two Sn moieties whereas the reaction with benzonitrile leads to a sixteen-membered ring system through C-H activation.


[UP] M. Krieg, F. Reicherter, P. Haiss, M. Stroebele, K. Eichele, M.-J. Treanor, R. Schaub, H. F. Bettinger:
Aufbau eines intern B3N3-dotierten Nanographenmoleküls
Angew. Chem. 2015, 127 8402-8404.
DOI: 10.1002/ange.201412165

Hier wird die Synthese eines Hexa-peri-hexabenzocoronens (HBC) mit innerem Borazinkern beschrieben. Die Festkörperstruktur dieses Bor-Stickstoff-dotierten HBC (BN-HBC) ist isotyp mit derjenigen des ursprünglichen HBC. Aufnahmen mit dem Rastertunnelmikroskop zeigen, dass BN-HBC flach in zweidimensionalen Mustern auf einer Au(111)-Oberfläche aufliegt.


[UP] M. Krieg, F. Reicherter, P. Haiss, M. Stroebele, K. Eichele, M.-J. Treanor, R. Schaub, H. F. Bettinger:
Construction of an Internally B3N3-Doped Nanographene Molecule
Angew. Chem. Int. Ed. 2015, 54(28), 8284-8286.
DOI: 10.1002/anie.201412165

The synthesis of a hexa-peri-hexabenzocoronene (HBC) with a central borazine core is described. The solid-state structure of this BN-doped HBC (BN-HBC) is isotypic with that of the parent HBC. Scanning tunneling microscopy shows that BN-HBC lies flat on Au(111) in a two-dimensional pattern.


[UP] U. Aygül, H.-J. Egelhaaf, P. Nagel, M. Merz, S. Schuppler, K. Eichele, H. Peisert, T. Chassé, Thomas:
Photodegradation of C-PCPDTBT and Si-PCPDTBT: Influence of the Bridging Atom on the Stability of a Low-Band-Gap Polymer for Solar Cell Application
Chem. Phys. Chem. 2015, 16(2), 428-435.
DOI 10.1002/cphc.201402494

The kinetics of photodegradation and the reactivity of different sites of the low-band-gap polymers poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4-b']dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (C-PCPDTBT) and poly[2,6-(4,4-bis-(2-ethylhexyl)dithieno[3,2-b:2',3'-d]silole)-alt-4,7-(2,1,3-benzothiadiazole)] (Si-PCPDTBT) are investigated as thin films and are compared to those of poly(3-hexylthiophene) (P3HT). The decay kinetics are monitored with UV/Vis spectroscopy and the reactivity and product evolution are investigated with X-ray photoelectron spectroscopy (XPS). Both polymers exhibit higher stability than P3HT. The bridging atom in the cyclopentadithiophene (CPDT) subunit has a significant influence on the stability. Varying oxidation rates for the different elements were observed. In the case of Si-PCPDTBT, the silicon atom is oxidized primarily, whereas the photooxidation rates of the other elements are reduced relative to C-PCPDTBT. Additionally, XPS experiments with varying excitation energies reveal a significant reaction gradient within a few nanometers of the surface of degraded thin films of C-PCPDTBT.


[UP] T. Gädt, J.-A. Dimmer, S. Fleischhauer, A. Frank, C. Nickl, T. Wütz, K. Eichele, L. Wesemann:
Oxidation of Germa- and Stanna-closo-dodecaborate
Dalton Trans. 2015, 44, 4726-4731.
DOI: 10.1039/c5dt00099h

The oxidation of closo-heteroborates [GeB11H11]2- and [SnB11H11]2- is presented. Upon oxidation germa-closo-dodecaborate yields a symmetrical dimer exhibiting a Ge–Ge bond between two clusters. This dimer shows sulphur insertion into the Ge–Ge bond at room temperature. In contrast, oxidation of the homologous tin cluster results in an unsymmetrical dimer bearing an Sn–B bond between two clusters. The Sn–B dimer is also the product of the hydride abstraction reaction. In the presence of the donor ligand 2,2'-bipyridine, the oxidation of closo-cluster [SnB11H11]2- leads to the Sn(IV)-half sandwich coordination compound [bipy-SnB11H11] which dissolves in DMSO to give the Sn(IV)-adduct [bipy(DMSO)-SnB11H11].


[UP] M. Ströbele, K. Eichele, H.-J. Meyer:
Cluster Harvesting in the WBr6–P System
Inorg. Chem. 2015, 54(3), 989–992.
DOI 10.1021/ic502333u

A combined thermal scanning–X-ray diffraction (XRD) approach was performed for the WBr6–P system to detect and analyze phases in this system, including metal-rich phases generated with increasing amounts of elemental (red) phosphorus under partial PBr3 release. Phases were characterized by powder XRD. A black crystalline powder of W4(PBr)Br10 was obtained after reduction of WBr6 with elemental phosphorus at 450 °C. The crystal structure of the new compound was found to be isotypic with the structure of W4(PCl)Cl10 on the basis of powder XRD data. The structure of W4(PBr)Br10 is represented by a cyclobutadiene-like tetranuclear tungsten cluster interconnected into a layered (W44-PBr)Br6i)Br8/2a-a arrangement via outer bromide ligands. The µ4-capping bromophosphinidene ligand was verified by solid-state magic-angle spinning 31P NMR spectroscopy.


[UP] A. Seyboldt, B. Wucher, S. Hohnstein, K. Eichele, F. Rominger, K. W. Toernroos, Karl W.:
Evidence for the Formation of Anionic Zerovalent Group 10 Complexes as Highly Reactive Intermediates
Organometallics 2015, 34(12), 2717-2725.
DOI: 10.1021/om500836m

The in situ generated CNC pincer lithium complex [Li(bimca)] (2) (bimca = bis(3-methylimidazolin-2-ylidene)carbazolide) reacts with M = Pt(0), Pd(0), and Ni(0) precursors under formal oxidative addition to (bimca)hydrido M(II) complexes 3. This unusual reaction involves proton abstraction that can derive from various sources including the ligand itself. Mechanistic considerations are given. The respective [M(bmica)Cl] complexes 4 have been prepared from the hydrido complexes 3 and subjected to reduction in order to identify a proposed zerovalent anionic [M(bimca)]- complex. In the case of M = Pt, only the (bimca)hydrido Pt(II) complex is observed, whereas, for [Pd(bimca)Cl], a dimeric Pd(0) complex [Pd2(bimca)2]K2 (6) bearing an anionic carbazole moiety is formed in the solid state. NMR DOSY experiments show that, in solution, this dimer dissociates to the monomeric anionic complex [Pd(bimca)]- (5b). We conclude that such anionic zerovalent complexes are plausible intermediates in the synthesis of group 10 metal(II) complexes from the respective metal(0) species with anionic CNC ligands.

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