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Université de Fribourg

Synthesis and Stereochemical Properties of Chiral Square Complexes of Iron(II)

Bark, Thomas ; Zelewsky, Alexander von ; Rappoport, Dmitrij ; Neuburger, Markus ; Schaffner, Silvia ; Lacour, Jérôme ; Jodry, Jonathan

In: Chemistry - A European Journal, 2004, vol. 10(19), p. 4839-4845

The hexadentate, and ditopic ligand 2,5-bis([2,2']bipyridin-6-yl)pyrazine yields a chiral, tetrameric, square-shaped, self-assembled species upon complexation with Fe²⁺ ions. The racemate of this complex was resolved with antimonyl tatrate as the chiral auxiliary. The purity of the enantiomer was determined by NMR spectroscopy, by using a chiral, diamagnetic shift reagent, and by circular...

Université de Neuchâtel

Enantiodiscrimination between an N-Acetyl-L-cysteine SAM and Proline : An In Situ Spectroscopic and Computational Study

Bieri, Marco ; Bürgi, Thomas

In: ChemPhysChem, 2006, vol. 7, p. 514-523

A combination of attenuated total reflection infrared (ATR-IR) and modulation excitation spectroscopy (MES) is used to study the enantiodiscriminating interactions between proline and a chiral, self-assembled monolayer (SAM) of N-acetyl-L-cysteine on gold. The N-acetyl-L-cysteine SAM consists of a mixture of protonated and deprotonated molecules. Whereas both species are influenced...

Université de Neuchâtel

Geometrical and electronic structure of Pd clusters on graphite

Bovet, M. ; Boschung, E. ; Hayoz, J. ; Pillo, Th. ; Dietler, G. ; Aebi, Philipp

In: Surface Science, 2001, vol. 473, no. 1-2, p. 17-24

Pd clusters formed by physical vapor deposition at room temperature (RT) on highly oriented pyrolytic graphite were investigated by a combination of X-ray photoelectron spectroscopy and diffraction, angle-resolved ultraviolet photoelectron spectroscopy, scanning tunneling microscopy and calculations based on the local density functional theory. Different coverages with nominally 3, 5 and 10 Å...

Université de Fribourg

Polytopal rearrangement of [Ni(acac)₂(py)]: A new square pyramid ⇄ trigonal bipyramid twist mechanism

Daul, Claude ; Niketic, Svetozar ; Rauzy, Cédrick ; Schläpfer, Carl-Wilhelm

In: Chemistry - A European Journal, 2004, vol. 10(3), p. 721-727

The interconversion mechanisms between three idealized polytopal forms (a square pyramid and two trigonal bipyramids) of [M(bidentate)₂(unidentate)] were investigated by an original combination of molecular mechanics (MM) and density functional theory (DFT) approaches. MM was used to model the mechanistic rearrangement path, and DFT to study selected points along this path. The test case was a...


Ab initio study of the work functions of elemental metal crystals

Fall, Caspar ; Baldereschi, Alfonso (Dir.)

Thèse sciences Ecole polytechnique fédérale de Lausanne EPFL : 1999 ; no 1955.

Université de Fribourg

Radical Cations of Phenyl-Substituted Aziridines: What Are the Conditions for Ring Opening ?

Gaebert, Carsten ; Mattay, Jochen ; Toubartz, Marion ; Steenken, Steen ; Müller, Beat ; Bally, Thomas

In: Chemistry - A European Journal, 2005, vol. 11(4), p. 1294-1304

Radical cations were generated from different phenyl-substituted aziridines by pulse radiolysis in aqueous solution containing TlOH.+, N₃. or SO₄.- as oxidants or in n-butyl chloride, by ⁶⁰Co γ radiolysis in Freon matrices at 77 K, and in some cases by flash photolysis in aqueous solution. Depending on the substitution pattern of the aziridines, two...

Université de Neuchâtel

Use of angle-resolved photoemission and density functional theory for surface structural analysis of YSi2

Koitzsch, Christian ; Bovet, M. ; Garnier, Michael Bernard Gunnar ; Aebi, Philipp ; Rogero, C. ; Martín-Gago, J. A.

In: Surface Science, 2004, vol. 566-568, no. 2, p. 1047-1051

The atomic structure of two-dimensional yttrium silicide epitaxially grown on Si(1 1 1) was investigated by means of density functional theory calculations and angle-resolved photoemission experiments. The obtained accuracy of the calculations allowed to discriminate different surface arrangements in a quantitative way via comparing their theoretical band structure to the experimental result....

Université de Neuchâtel

Framework Fluxionality of Organometallic Oxides : Synthesis, Crystal Structure, EXAFS, and DFT Studies on [{Ru(η6-arene)}4Mo4O16] Complexes

Laurencin, Danielle ; Fidalgo, Eva Garcia ; Villanneau, Richard ; Villain, Françoise ; Herson, Patrick ; Pacifico, Jessica ; Stoeckli-Evans, Helen ; Bénard, Marc ; Rohmer, Marie-Madeleine ; Süss-Fink, Georg ; Proust, Anna

In: Chemistry - A European Journal, 2003, vol. 10, p. 208-217

Reactions of the molybdates Na2MoO4•2 H2O and (nBu4N)2[Mo2O7] with [{Ru(arene)Cl2}2] (arene=C6H5CH3, 1,3,5-C6H3(CH3)3, 1,2,4,5-C6H2(CH3)4) in water or organic solvents...

Université de Fribourg

pH-dependent coordination of AgI ions by histidine: experiment, theory, and a model for SilE

Mirolo, Laurent ; Schmidt, Tobias ; Eckhardt, Sonja ; Meuwly, Markus ; Fromm, Katharina M.

In: Chemistry - A European Journal, 2013, vol. 19, no. 5, p. 1754–1761

Artificial implants and biomaterials lack the natural defense system of our body and, thus, have to be protected from bacterial adhesion and biofilm formation. In addition to the increasing number of implanted objects, the resistance of bacteria is also an important problem. Silver ions are well-known for their antimicrobial properties, yet not a lot is known about their mode of action. Silver is...

Université de Fribourg

Magnetic anisotropy in ‘scorpionate’ first-row transition-metal complexes: a theoretical investigation

Perić, Marko ; García-Fuente, Amador ; Zlatar, Matija ; Daul, Claude ; Stepanović, Stepan ; García-Fernández, Pablo ; Gruden-Pavlović, Maja

In: Chemistry – A European Journal, 2015, vol. 21, no. 9, p. 3716–3726

In this work we have analyzed in detail the magnetic anisotropy in a series of hydrotris(pyrazolyl)borate (Tp−) metal complexes, namely [VTpCl]+, [CrTpCl]+, [MnTpCl]+, [FeTpCl], [CoTpCl], and [NiTpCl], and their substituted methyl and tert-butyl analogues with the goal of observing the effect of the ligand field on the magnetic properties. In the [VTpCl]+, [CrTpCl]+, [CoTpCl], and [NiTpCl]...