Klaus Eichele Publication Abstracts 2004

 

---

[UP]

K. Eichele, C. Nachtigal, S. Jung, H. A. Mayer, E. Lindner, M. Ströbele: A Simple Molecule with a Complex Crystal Structure: Interplay of 31P Solid-State NMR Spectroscopy and Single-Crystal X-ray Diffraction in the Structure Determination of a Ruthenium Diphosphine Diamine Complex. Magn. Reson. Chem. 2004, 42, 807-813. DOI 10.1002/mrc.1433

A comprehensive ³¹P solid-state NMR study of Ru(h¹-Ph₂PCH₂CH₂OCH₃)₂(h²-en)Cl₂ (en = ethylenediamine) (1), by 1D (contact time variation, inversion–recovery, SPARTAN) and 2D techniques (homonuclear J-resolved, SECSY) indicated that the crystal structure of 1 should be complex. The single-crystal x-ray structure determination confirmed the presence of eight independent molecules in the asymmetric unit, with ³¹P isotropic chemical shifts in the range 27.3–40.1 ppm, while the spans of the phosphorus chemical shift tensors are of the order of 170 ppm. Based on unique structural features and NMR data, one molecule has been tentatively assigned.

---

[UP]	I. Warad, K. Eichele, H. A. Mayer, E. Lindner: Supported organometallic complexes part 39: cationic diamine(ether–phosphine)ruthenium(II) complexes as precursors for the hydrogenation of trans-4-phenyl-3-butene-2-one Inorg. Chim. Acta 2004, 357, 1847-1853. DOI 10.1016/j.ica.2003.12.015

Treatment of RuCl₂(eta¹-Ph₂PCH₂CH₂ OCH₃)₂(diamine) (1L₁– 1L₇) with one equivalent of AgX (X=OTf, BF₄) in CH₂Cl₂ results in the formation of the monocationic ruthenium(II) complexes [RuCl(eta¹-Ph₂PCH₂CH₂OCH₃) (eta²-Ph₂PCH₂CH₂OCH₃)(diamine)]⁺ X^- (2L₁–2L₇ ). These complexes were characterized by NMR, and mass spectroscopy as well as by elemental analyses, 2L₁ additionally by an X-ray structural analysis. Complex 2L₁ crystallizes in the monoclinic space group C2/c with Z=8. The monocationic and neutral complexes were applied as catalysts in the selective hydrogenation of trans-4-phenyl-3-butene-2-one. With the exception of 1L₃/1L ₇ and 2L₃/2L ₇ all catalysts showed high activities and selectivities toward the hydrogenation of the carbonyl group under mild conditions. However, the activity of the cationic catalysts is only half of that of their neutral congeners.

---

[UP]	N. Kuhn, A. Abu-Rayyan, K. Eichele, S. Schwarz, M. Steimann: Weak interionic interactions in 2-bromoimidazolium derivatives. Inorg. Chim. Acta 2004, 357, 1799-1804. DOI 10.1016/j.ica.2003.10.038

The 2-bromoimidazolium bromide [ImBr]Br (5, Im=2,3-dihydro-1,3-diisopropyl- 4,5-dimethylimidazol-2-ylidene) is prepared from Im (4) and bromine. From 4 and CBr₄, the adduct [ImBr]Br · CBr₄ (6) is obtained. 5 reacts with TeBr₄ to give the salt [ImBr][TeBr₅] (7). The crystal structures of 5–7 reveal the presence of weak interionic Br to Br interactions which are discussed on comparison with the structure of [ImI]I (8) and similar compounds.

---

[UP]	N. Kuhn, A. Abu-Rayyan, K. Eichele, C. Piludu, M. Steimann: Weak Interionic Interactions in 2-Haloimidazolium Hexahalotellurates(IV) Z. Anorg. Allg. Chem. 2004, 630, 495-497. DOI 10.1002/zaac.200300401

The 2-haloimidazolium salts [C₁₁H₂₀N₂X]X [1; X = Cl (a), Br (b)] react with TeX₄ to give the salts [C₁₁H₂₀N₂X]₂[TeX₆] [2; X = Cl (a), Br (b)]. The crystal structure analyses of 2a and 2b · CH₂Cl₂ reveal the presence of ionic pairs linked by weak halogen to halogen interactions.