Sunna Ó. Wallevik
University of Iceland
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Sunna Ó. Wallevik.
Organometallics | 2007
Andras Bodi; Ágúst Kvaran; Sigridur Jonsdottir; Egill Antonsson; Sunna Ó. Wallevik; Ingvar Arnason; Alexander V. Belyakov; Alexander A. Baskakov; Margit Hölbling; Heinz Oberhammer
The molecular structures of axial and equatorial conformers of 1-fluorosilacyclohexane, C5H10SiHF, as well as the thermodynamic equilibrium between these species were investigated by means of gas electron diffraction (GED), dynamic nuclear magnetic resonance, temperature-dependent Raman spectroscopy, and quantum chemical calculations (MP2, DFT, and composite methods). According to GED, the compound exists in the gas phase as a mixture of two conformers possessing the chair conformation of the six-membered ring and Cs symmetry and differing in the axial or equatorial position of the Si-F bond (axial ) 63(8) mol %/equatorial ) 37(8) mol %) at T ) 293 K, corresponding to an A value of –0.31(20) kcal mol. Density functional theory (DFT) calculations were employed to obtain the minimal energy path of the conformational inversion. The MP2, G3B3, and CBS-QB3 methods were also employed to calculate the equilibrium geometries and energies of the local minima in the gas phase and in solution. The gas-phase results are in good agreement with the experiment, whereas a combined PCM/IPCM(B3LYP/6-311G(d)) approach overestimates the stabilization of the axial conformer by 0.3-0.4 kcal mol in solution at 112 K. Temperature-dependent Raman spectroscopy in the temperature ranges of 210–300 K (neat liquid), 120–300 K (pentane solution), and 200–293 K (dichloromethane solution) also indicates that the axial conformer is favored over the equatorial one by 0.25(5), 0.22(5), and 0.28(5) kcal mol (∆H values), respectively.
Russian Journal of Physical Chemistry A | 2012
Alexander V. Belyakov; Alexander A. Baskakov; V. N. Naraev; Anatolii N. Rykov; Heinz Oberhammer; Ingvar Arnason; Sunna Ó. Wallevik
The molecular structure of axial and equatorial conformer of the 1-bromo-1-silacyclohexane molecule, CH2(CH2CH2)2SiH-Br, as well as thermodynamic equilibrium between these species are investigated by means of gas-phase electron diffraction and quantum chemistry on the MP2(full)/SDB-AUG-cc-PVTZ level of theory. It is revealed that according to electron diffraction data, the compound exists in the gasphase as a mixture of conformers possessing the chair conformation of the six-membered ring and Cs symmetry and differing in the axial and equatorial position of the Si-Br bond (ax. = 80(5) mol %, eq. = 20(7) mol %) at 352 K, that corresponds to the value of A = (Gax○ − Geq○) = −0.82(32) kcal/mol. It is found that observed data agree well with theoretical ones. Using Natural Bond Orbital (NBO) analysis it is revealed that axial conformer of 1-bromo-1-silacyclohexane molecule is an example of the stabilization of the form that is unfavorable from the point of view of steric effects and effects of conjugations. It is concluded that stabilization is achieved due to electrostatic interactions.
Journal of Physical Chemistry A | 2015
Sarah L. Masters; Heather E. Robertson; Derek A. Wann; Margit Hölbling; Karl Hassler; Ragnar Bjornsson; Sunna Ó. Wallevik; Ingvar Arnason
The molecular structure of 1,2-bis(trifluoromethyl)-1,1,2,2-tetramethyldisilane has been determined in three different phases (solid, liquid, and gas) using various spectroscopic and diffraction techniques. Both the solid-state and gas-phase investigations revealed only one conformer to be present in the sample analyzed, whereas the liquid phase revealed the presence of three conformers. The data have been reproduced using computational methods and a rationale is presented for the observation of three conformers in the liquid state.
Journal of Molecular Structure | 2010
Sunna Ó. Wallevik; Ragnar Bjornsson; Ágúst Kvaran; Sigridur Jonsdottir; Georgiy V. Girichev; N. I. Giricheva; Karl Hassler; Ingvar Arnason
Journal of Raman Spectroscopy | 2012
Thomas Kern; Margit Hölbling; Ana Dzambaski; Michaela Flock; Karl Hassler; Sunna Ó. Wallevik; Ingvar Arnason; Ragnar Bjornsson
Journal of Molecular Structure | 2012
A.V. Belyakov; A.A. Baskakov; Raphael J. F. Berger; Norbert W. Mitzel; Heinz Oberhammer; Ingvar Arnason; Sunna Ó. Wallevik
Organometallics | 2013
Sunna Ó. Wallevik; Ragnar Bjornsson; Ágúst Kvaran; Sigridur Jonsdottir; Ingvar Arnason; Alexander V. Belyakov; Thomas Kern; Karl Hassler
Structural Chemistry | 2015
Alexander V. Belyakov; Yurii Sigolaev; Sergey A. Shlykov; Sunna Ó. Wallevik; Nanna R. Jonsdottir; Ragnar Bjornsson; Sigridur Jonsdottir; Ágúst Kvaran; Thomas Kern; Karl Hassler; Ingvar Arnason
Journal of Molecular Structure | 2017
Alexander V. Belyakov; Yrii F. Sigolaev; Sergey A. Shlykov; Sunna Ó. Wallevik; Nanna R. Jonsdottir; Sigridur Jonsdottir; Ágúst Kvaran; Ragnar Bjornsson; Ingvar Arnason
Journal of Molecular Structure | 2018
Sergey A. Shlykov; Boris V. Puchkov; Ingvar Arnason; Sunna Ó. Wallevik; N. I. Giricheva; Georgiy V. Girichev; Yuriy A. Zhabanov