Klaus Eichele Publication Abstracts 2016

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[UP]	W. Scherer, P. Meixner, K. Batke, J. E. Barquera-Lozada, K. Ruhland, A. Fischer, G. Eickerling, K. Eichele: J(Si,H)-Kopplungskonstanten in nicht-klassischen Übergangsmetallsilankomplexen Angew. Chem. 2016, 128(38), 11846-11850. DOI: 10.1002/ange.201604001

Wir werden herausarbeiten, dass das Vorzeichen und der Betrag der J(Si,H)-Kopplungskonstante hochsensible Kriterien zur Bestimmung des Fortschritts der Si-H-Bindungsaktivierung in nicht-klassischen Silankomplexen darstellen. Bisher war die Analyse dieser wichtigen Struktur/Eigenschafts-Beziehung durch fehlerhafte J(Si,H)-Vorzeichen in der Literatur erschwert. Die hier vorgestellten neuen Erkenntnisse helfen dabei, ausgewählte Kontrollparameter der Si-H-Bindungsaktivierung auch in nicht-klassischen Silankomplexen zu identifizieren.

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[UP]	W. Scherer, P. Meixner, K. Batke, J. E. Barquera-Lozada, K. Ruhland, A. Fischer, G. Eickerling, K. Eichele: J(Si,H) Coupling Constants in Nonclassical Transition-Metal Silane Complexes Angew. Chem. Int. Ed. 2016, 55(38), 11673-11677. DOI: 10.1002/anie.201604001

We will outline that the sign and magnitude of J(Si,H) coupling constants provide a highly sensitive tool to measure the extent of Si-H bond activation in nonclassical silane complexes. Up to now, this structure-property relationship was obscured by erroneous J(Si,H) sign determinations in the literature. These new findings also help to identify the salient control parameters of the Si-H bond activation process in nonclassical silane complexes.

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[UP]	J. Schneider, K. M. Krebs, S. Freitag, K. Eichele, H. Schubert, L. Wesemann: Intramolecular Tetrylene Lewis Adducts: Synthesis and Reactivity Chem. Eur. J. 2016, 22(28), 9812-9826. DOI: 10.1002/chem.201601224

A series of benzyl(diphenylphosphino) and o-phenyl(diphenlyphosphino) substituted germylenes and plumbylenes were synthesized by nucleophilic substitution between the respective lithium reagent and tetrylene halide. The Lewis pairs were characterized by X-ray crystallography and NMR spectroscopy. The reactivity of the tetrylenes was investigated with respect to azide addition. In the germylene case, the germaniumimide was formed as the kinetically controlled product, which rearranges upon heating to give the phosphinimide. The stannylene and plumbylene derivatives react with adamantylazide to give the azide adducts. 1-Pentene reacts diastereoselectively with the phosphagermirane to give a cyclic addition product. Trimethysilylacetylene shows an addition with the benzylphosphino- substituted germylene and plumbylene to give the cycloheteropentene molecules. The addition product between phenylacetylene and the four membered Ge-P adduct shows after addition at room temperature a 1,4-phenylmigration to give a cyclic phosphine. Alkylnitrene insertion into a Ge-C bond of the alkyne addition product of the phosphagermirane was found in reaction with adamantylazide.

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[UP]	J. Arras, K. Eichele, B. Maryasin, H. Schubert, C. Ochsenfeld, L. Wesemann: Intermolecular (119)Sn,(31)P Through-Space Spin-Spin Coupling in a Solid Bivalent Tin Phosphido Complex Inorg. Chem. 2016, 55(9), 4669-4675. DOI: 10.1021/acs.inorgchem.6b00573

A bivalent tin complex [Sn(NP)2] (NP = [(2-Me2NC6H4)P(C6H5)](-)) was prepared and characterized by X-ray diffraction and solution and solid-state nuclear magnetic resonance (NMR) spectroscopy. In agreement with the X-ray structures of two polymorphs of the molecule, (31)P and (119)Sn CP/MAS NMR spectra revealed one crystallographic phosphorus and tin site with through-bond (1)J((117/119)Sn,(31)P) and through-space (TS)J((117/119)Sn,(31)P) spin-spin couplings. Density functional theory (DFT) calculations of the NMR parameters confirm the experimental data. The observation of through-space (TS)J((117/119)Sn,(31)P) couplings was unexpected, as the distances of the phosphorus atoms of one molecule and the tin atom of the neighboring molecule (>4.6 A) are outside the sum of the van der Waals radii of the atoms P and Sn (4.32 A). The intermolecular Sn···P separations are clearly too large for bonding interactions, as supported by a natural bond orbital (NBO) analysis.