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Université de Fribourg

Rhodium(iii) complexes containing C4-bound N-heterocyclic carbenes: synthesis, coordination chemistry, and catalytic activity in transfer hydrogenation

Yang, Liangru ; Krüger, Anneke ; Neels, Antonia ; Albrecht, Martin

In: Organometallics, 2008, vol. 27, no. 13, p. 3161–3171

Direct metalation of C2-protected diimidozolium salts with RhCl₃ or [RhCl(cod)]₂ and KI afforded a series of new rhodium(III) complexes with abnormally C4-bound, cis-chelating NHC ligands. The complexes were isolated as dimetallic species containing two (μ²-I)₃-bridged rhodium(III) centers. In the presence of coordinating ligands such as CH₃CN, PPh₃, or dppe, the dimeric...

Université de Fribourg

Piano-stool iron(ii) complexes as probes for the bonding of n-heterocyclic carbenes: indications for -acceptor ability

Mercs, Laszlo ; Labat, Gaël ; Neels, Antonia ; Ehlers, Andreas ; Albrecht, Martin

In: Organometallics, 2006, vol. 25, no. 23, p. 5648 -5656

A series of new piano-stool iron(II) complexes comprising mono- and bidentate chelating N-heterocyclic carbene ligands [Fe(cp)(CO)(NHC)(L)]X have been prepared and analyzed by spectroscopic, electrochemical, crystallographic, and theoretical methods. Selectively substituting the L site with a series of ligands going from carbene to pyridine to CO suggests that CO is the strongest π...

Université de Fribourg

Palladium complexes comprising C(4)-bound diimidazolylidene carbenes

Heckenroth, Marion ; Albrecht, Martin

In: Chimia, 2008, vol. 62, no. 4, p. 253-255

Imidazolium-derived palladium dicarbene complexes have been synthesized which feature either normal C(2) carbene bonding or abnormal C(4) bonding. Comparison of the reactivity of these complexes, in particular towards Lewis acids (H⁺, Ag⁺), indicate consistently that C(4)-bound carbenes are stronger donors than their C(2)-bound analogs. As a consequence of this electronic impact, palladium...

Université de Fribourg

Decreased infarct size after focal cerebral ischemia in mice chronically infected with Toxoplasma gondii

Arsenijevic, Denis ; Bilbao, F. de ; Vallet, Philippe ; Hemphill, Andrew ; Gottstein, B. ; Richard, Denis ; Giannakopoulos, Panteleimon ; Langhans, Wolfgang

In: Neuroscience, 2007, vol. 150, no. 3, p. 537-546

To determine whether Toxoplasma gondii infection could modify biological phenomena associated with brain ischemia, we investigated the effect of permanent middle cerebral artery occlusion (MCAO) on neuronal survival, inflammation and redox state in chronically infected mice. Infected animals showed a 40% to 50% decrease of infarct size compared with non-infected littermates 1, 4 and 14 days after...

Université de Fribourg

The circadian clock and mood-related behavior : addendum to Hampp G. et al., Regulation of monoamine oxidase a by circadian-clock components implies clock influence on mood. Curr Biol 18:678–83, 2008.

Hampp, Gabriele ; Albrecht, Urs

In: Communicative & Integrative Biology, 2008, vol. 1, no. 1, p. 1-3

Over many years evidence accumulated that circadian rhythms are related to psychiatric disorders.1-3 However, a mechanistic relationship between the circadian clock and mood related behaviors remained enigmatic. Now, we have reported that monoamine oxidase A (MAOA), a mitochondrial enzyme degrading catecholamines including dopamine, is regulated by components of the circadian clock .4...

Université de Fribourg

A mathematical model for the steady activation of a skeletal muscle

Gabriel, Jean-Pierre ; Studer, L. M. ; Rüegg, Dieter G. ; Schnetzer, M.-A.

In: SIAM Journal on Applied Mathematics, 2008, vol. 68, no. 3, p. 869-889

A skeletal muscle is composed of motor units, each consisting of a motoneuron and the muscle fibers it innervates. The input to the motor units is formed of electrical signals coming from higher motor centers and propagated to the motoneurons along a network of nerve fibers. Because of its complexity, this network still escapes actual direct observations. The present model describes the steady...

Université de Fribourg

Fourier and barycentric formulae for equidistant Hermite trigonometric interpolation

Berrut, Jean-Paul ; Welscher, Annick

In: Applied and Computational Harmonic Analysis, 2007, vol. 23, no. 3, p. 307-320

We consider the Hermite trigonometric interpolation problem of order 1 for equidistant nodes, i.e., the problem of finding a trigonometric polynomial t that interpolates the values of a function and of its derivative at equidistant points. We give a formula for the Fourier coefficients of t in terms of those of the two classical trigonometric polynomials interpolating the values and those of the...

Université de Fribourg

Co-occurrence of the foraminifer Mohlerina basiliensis with Bacinella–Lithocodium oncoids: palaeoenvironmental and palaeoecological implications (Late Oxfordian, Swiss Jura)

Védrine, Stéphanie

In: Journal of Micropalaeontology, 2008, vol. 27, p. 35-44

The stratigraphical and spatial distribution of the foraminifer Mohlerina basiliensis and Bacinella–Lithocodium oncoids was studied in the lagoonal deposits of the oncoid-rich Hauptmumienbank Member from the Swiss Jura Mountains (Late Oxfordian, NW Switzerland). Mohlerina basiliensis has a double-layered wall structure (thick outer hyaline-radial calcite layer with a lamellar structure and...