Biomedical subjects

Ulrich Fekl

Publications and source records attributed to Ulrich Fekl.

4 recordsLinked to original sources

PubMed2006

Neutral high-potential nickel triad bisdithiolenes: structure and solid-state NMR properties of Pt[S2C2(CF3)2]2.

X-ray crystallography and solid-state NMR techniques were used to determine the structure and 195Pt NMR chemical shift (CS) tensor of Pt[S2C2(CF3)2]2. This is the first reported crystal structure of a highly oxidizing (CN- or CF3-substituted) neutral bis(dithiolene) complex of a Ni triad metal in its pure form. The 195Pt NMR CS tensor is highly anisotropic and asymmetric; the latter property is attributed to the noninnocent nature of the ligand. The tensor components and orientation are determined with density functional theory calculations.

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PubMed2006

New insight into reactions of Ni(S2C2(CF3)2)2 with simple alkenes: alkene adduct versus dihydrodithiin product selectivity is controlled by [Ni(S2C2(CF3)2)2]- anion.

The nickel bis(dithiolene) complex Ni(S2C2(CF3)2)2 employs its sulfur centers in reactions with alkenes, and stable interligand S-bonded alkene adducts can be formed. The present study shows that the selectivity of alkene binding to charge-neutral Ni(S2C2(CF3)2)2 is influenced by the anion [Ni(S2C2(CF3)2)2]-. In the absence of anion, formation of substituted dihydrodithiins (intraligand addition) dominates, whereas the presence of anion allows for the formation of stable interligand adducts. Mechanistic implications are discussed. The X-ray crystal structure of the ethylene adduct of Ni(S2C2(CF3)2)2 is presented, displaying interligand binding of ethylene to sulfur centers in the bis(dithiolene) complex.

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PubMed2003

Beta-diiminate platinum complexes for alkane dehydrogenation.

New five-coordinate Pt(IV) complexes [{(o-R2-p-R'-C6H2)NC(R' ')}2CH]PtMe3 (R, R', R' ' = alkyl or H) are reported. The complex with R = Me, R' = tBu, R' ' = Me generates unsaturated Pt(II) species capable of alkane C-H bond activation and stoichiometric dehydrogenation.

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PubMed2002

Five-coordinate platinum(IV) complex as a precursor to a novel Pt(II) olefin hydride complex for alkane activation.

The five-coordinate platinum(IV) complex (nacnac)PtMe3 (nacnac- = [{(o-iPr2C6H3)NC(CH3)}2CH]-) thermally eliminates ethane and methane to produce a novel olefin(hydrido)platinum(II) complex, where the olefin is part of the nacnac-type ligand. This Pt(II) product activates hydrocarbons, including alkanes under mild conditions, as indicated by scrambling of hydrogen and deuterium between the hydrocarbon solvent and selected positions on the ligand of the platinum complex. A mechanism in which olefin insertion into the metal hydride bond opens a site to allow hydrocarbon coordination and C-H bond oxidative addition is proposed.

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