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Université de Fribourg

1,2,3-triazolylidenes as versatile abnormal carbene ligands for late transition metals

Mathew, Paulson ; Neels, Antonia ; Albrecht, Martin

In: Journal of the American Chemical Society, 2008, vol. 130, no. 41, p. 13534–13535

The [3 + 2] cycloaddition of azides and acetylenes followed by nitrogen quaternization was applied for the generation of novel and highly modular triazolium salts. The selective substitution of the 1,3,4-substitution pattern presets such salts as precursors for a new class of abnormal carbene ligands, thus expanding the family of these high-impact ligands. Metalation of the triazolium salts is...

Université de Fribourg

1,4-Dimethylenespiropentane: a unique model system for studying fermi resonance in raman optical activity

Hug, Werner ; Haesler, Jacques ; Kozhushkov, Sergei I. ; Meijere, Armin de

In: ChemPhysChem, 2007, vol. 8, no. 8, p. 1161 - 1169

The C₂-symmetric title compound, a small, rigid hydrocarbon molecule with two distinct, strongly interacting vibrational chromophores, represents a unique model system for testing computational approaches to Raman optical activity (ROA) beyond the isolated molecule and the harmonic approximation. We show that the experimental Raman and ROA spectra are marked by the presence of strong Fermi...

Université de Fribourg

¹⁸²Tungsten Mössbauer spectroscopy of heteropolytungstates

Bochet, Christian G. ; Draper, Thérèse ; Bocquet, Bernard ; Pope, Michael T. ; Williams, Alan F.

In: Dalton Transaction, 2009, vol. 26, p. 5127-5131

The tungsten-182 Mössbauer spectra of a series of Keggin structure heteropolytungstates, [EW₁₂O₄₀]ⁿ⁻ are reported. There is a very considerable variation in quadrupole coupling at the tungsten nucleus indicating considerable asymmetry in the electron distribution for the more electronegative elements E. The quadrupole coupling correlates well with the structural data, in...

Consortium of Swiss Academic Libraries

3rd Early Career Issue

Vermant, J. ; Winter, H.

In: Rheologica Acta, 2014, vol. 53, no. 12, p. 883-884

Université de Fribourg

4-Hydroxy-1-naphthaldehydes: proton transfer or deprotonation

Manolova, Y. ; Kurteva, Vanya B. ; Antonov, Liudmil M. ; Marciniak, H. ; Lochbrunner, S. ; Crochet, Aurélien ; Fromm, Katharina M. ; Kamounah, Fadhil S. ; Hansen, P. E.

In: Physical Chemistry Chemical Physics, 2015, vol. 17, no. 15, p. 10238–10249

A series of naphthaldehydes, including a Mannich base, have been investigated by UV-Vis spectroscopy, NMR and theoretical methods to explore their potential tautomerism. In the case of 4-hydroxy-1-naphthaldehyde concentration dependent deprotonation has been detected in methanol and acetonitrile. For 4-hydroxy-3-(piperidin-1-ylmethyl)-1-naphthaldehyde (a Mannich base) an intramolecular proton...

Université de Fribourg

Ab initio prediction of a multiferroic with large polarization and magnetization

Baettig, Pio ; Spaldin, Nicola A.

In: Applied Physics Letters, 2005, vol. 86, p. 012505

We describe the design of a magnetic ferroelectric with large spontaneous magnetization and polarization using first-principles density functional theory. The usual difficulties associated with the production of robustly insulating ferromagnets are circumvented by incorporating the magnetism through ferrimagnetic behavior. We show that the ordered perovskite Bi₂FeCrO₆ will have a...

Université de Fribourg

Ab initio study of structural, electronic and thermodynamic properties of tungstate double perovskites Ba₂MWO₆ (M = Mg, Ni, Zn)

Sahnoun, Omar ; Bouhani-Benziane, H. ; Sahnoun, Mohammed ; Driz, Mohamed ; Daul, Claude A.

In: Computational Materials Science, 2013, vol. 77, p. 316–321

The structural and electronic properties of the double perovskite Ba₂MWO₆ with M = Mg, Ni, Zn have been studied using the full-potential linearized augmented plane wave (FP-LAPW) method by employing both the local density approximation (LDA) and the generalized gradient approximation (GGA), which are based on exchange–correlation energy optimization to calculate the total energy. Also we...