[Uni Tübingen] - [Mat.-Nat. Fakultät] - [Fachbereich Chemie] - [Anorg. Chemie] - [Klaus Eichele] - [Publications] - Abstracts 2008

Klaus Eichele Publication Abstracts 2008

 

[UP] M. Kirchmann, K. Eichele, F. M. Schappacher, R. Pöttgen, L. Wesemann:
Oktaedrische Koordinationsverbindungen der Ni, Pd, Pt-Triade
Angew. Chem. 2008, 120, 977-980.
DOI 10.1002/ange.200704814
Octahedral Coordination Compounds of the Ni, Pd, Pt Triad
Angew. Chem. Int. Ed. 2008, 47, 963-966.
DOI 10.1002/anie.200704814

Hoch hinaus: Die Koordination des Zinnliganden Stanna-closo-dodecaborat an Ni, Pd und Pt führt zur Bildung negativ geladener Komplexionen, die Metallzentren M mit hohen Koordinationszahlen und in hohen formalen Oxidationsstufen enthalten. Im Fall des Platinderivates wurde im 195Pt-NMR-Spektrum eine chemische Verschiebung bei sehr hohem Feld (δ= -7724 ppm) beobachtet.


[UP] M. Kirchmann, T. Gaedt, K. Eichele, L. Wesemann:
Nickel coordination compounds of stanna-closo-dodecaborate
Eur. J. Inorg. Chem. 2008, 2261-2265
DOI 10.1002/ejic.200800142

The reaction of the nickel complexes [(dppm)NiBr2] [dppm = 1,1-bis(diphenylphosphanyl)methane] and [(dppe)NiBr2] [dppe = 1,2-bis(diphenylphosphanyl)ethane] with stanna-closo-dodecaborate [Bu3NH]2[SnB11H11] (1) yielded the trigonal-bipyramidal coordination compounds [Bu3NH]4[(dppm)Ni(SnB11H11)3] (2) and [Bu3NH]4[(dppe)Ni(SnB11H11)3] (3). The square-planar compound [Bu3NH]2[(ImiPr2Me2)2Ni(SnB11H11)2] (4) (ImiPr2Me2 = 1,3-diisopropyl-4,5-dimethyl-imidazoliumylidene) could be obtained by the reaction of the N-heterocyclic carbene complex [(ImiPr2Me2)2NiBr2] with [Bu3NH]2[SnB11H11] (1). The new coordination compounds were characterized by heteronuclear NMR spectroscopy and single-crystal X-ray structure analysis.


[UP] M. Kirchmann, K. Eichele, L. Wesemann:
Homoleptic Cadmium and Mercury Compounds of Stanna-closo-dodecaborate
Inorg. Chem. 2008, 47, 5988-5991
DOI 10.1021/ic800357z

The reaction of stanna-closo-dodecaborate [SnB11H11]2- (1) with CdBr2 gave the tetrahedrally coordinated compound [Cd(SnB11H11)4]6- (2). The same coordination mode can be found in [Hg(SnB11H11)4]6- (3), which was obtained by reaction of stannaborate with Hg2Cl2. Both compounds were characterized by single crystal X-ray analysis and heteronuclear NMR techniques.


[UP] A. M. Winter, K. Eichele, H.-G. Mack, W. C. Kaska, H. A. Mayer:
Prototropic rearrangements in cycloheptatrienyl PCP pincer iridium complexes.
J. Chem. Soc., Dalton Trans. 2008, 527-532.
DOI 10.1039/b712712j

When the cycloheptatriene iridium(III) pincer complex (PCP)Ir(CO)(H)(Cl) (3) (PCP = 2,7-(CH2Pt Bu2)2C7 H5) is treated with the bases NaH, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and lithium 2,2,6,6-tetramethylpiperidide (LiTMP) under various conditions different products are obtained. At elevated temperatures and with DBU or LiTMP as a base the trans dihydride (PCP')Ir(CO)(H)2 (PCP' = 2-(CHPtBu2)- 7-(CH2PtBu2)C7 H4) (5) is formed where the π-system extends into one of the phosphine bridges. This compound loses H2 to give the square-planar iridium(I) carbonyl complex 7 (PCP'IrCO). The dihydride 5 can also rearrange to the new isomeric iridium(I) carbonyl 6 (PCP''IrCO, PCP'' = 2,7-(CH2PtBu2) 2C7H5). Thus the two hydrides have moved into the ligand backbone creating a methylene group in the 3-position of the cycloheptatriene ring. Alternatively, 6 is formed by a rearrangement from 6a which differs from 6 by having the methylene group in the 4-position of the cycloheptatriene ring. The iridium(I) carbonyl 6a in turn is made from 3 by treatment with DBU at room temperature. Interestingly, when compound 3 is heated to reflux in THF the hydrogen bound at the metal carbon is shifted to a carbon atom in the cycloheptatriene ring generating a ring methylene group (3a). From this complex HCl is eliminated upon chromatography forming 6 as the final product. Quantum chemical calculations at various levels of theory illustrate the relative energetic stabilities of all iridium complexes.


[UP] M. Kirchmann, K. Eichele, L. Wesemann:
Synthesis and Characterization of the Platinum(IV) Hydride [PtH(SnB11H11)5]7-
Organometallics 2008, 27, 6029-6031
DOI 10.1021/om8006536

The square-planar platinum(II) compound [Pt(SnB11H11)4]6- can be readily protonated in the presence of stanna-closo-dodecaborate, resulting in the formation of the octahedral platinum(IV) compound [PtH(SnB11H11)5]7-. When this reaction is carried out with DCl, the corresponding deuteride derivative [PtD(SnB11H11)5]7- can be obtained.

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