dc.contributor |
Háskóli Íslands |
dc.contributor |
University of Iceland |
dc.contributor.author |
Belyakov, Alexander V. |
dc.contributor.author |
Sigolaev, Yrii F. |
dc.contributor.author |
Shlykov, Sergey A. |
dc.contributor.author |
Wallevik, Sunna Ó. |
dc.contributor.author |
Jónsdóttir, Nanna R. |
dc.contributor.author |
Jónsdóttir, Sigríður |
dc.contributor.author |
Kvaran, Agust |
dc.contributor.author |
Bjornsson, Ragnar |
dc.contributor.author |
Árnason, Ingvar |
dc.date.accessioned |
2018-01-30T13:42:56Z |
dc.date.available |
2018-01-30T13:42:56Z |
dc.date.issued |
2017-03 |
dc.identifier.citation |
Belyakov, A. V., Sigolaev, Y. F., Shlykov, S. A., Wallevik, S. Ó., Jonsdottir, N. R., Jonsdottir, S., . . . Arnason, I. (2017). Conformational properties of 1-cyano-1-silacyclohexane, C5H10SiHCN: Gas electron diffraction, low-temperature NMR and quantum chemical calculations. Journal of Molecular Structure, 1132, 149-156. doi:https://doi.org/10.1016/j.molstruc.2016.10.012 |
dc.identifier.issn |
0022-2860 |
dc.identifier.uri |
https://hdl.handle.net/20.500.11815/547 |
dc.description.abstract |
The conformational preference of the cyano group of the 1-cyano-1-silacyclohexane was studied experimentally by means of gas electron diffraction (GED) and dynamic nuclear magnetic resonance (DNMR) as well as by quantum chemical (QC) calculations applying high-level coupled cluster methods as well as DFT methods. According to the GED experiment, 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 while differing in the axial or equatorial position of the substituent (axial = 84(12) mol %/equatorial = 16(12) mol %) at T = 279(3) K, corresponding to an A value (Gax – Geq) of −1.0(4) kcal mol−1. Gas-phase CCSD(T) calculations predict an A value of −0.72 kcal mol−1 at 279 K. In contrast, the low-temperature 13C NMR experiments resulted in an axial/equatorial ratio of 35/65 mol % at 120 K corresponding to an A value of 0.14 kcal mol−1. An average value for ΔG#e→a = 5.6 ± 0.1 kcal mol−1 was obtained for the temperature range 110–145 K. The dramatically different conformational behaviour in the gas-phase (GED) compared to the liquid phase (DNMR) suggests a strong solvation effect. According to natural bond orbital analysis the axial conformer of the title compound is an example of stabilization of a form, which is not favored by electrostatic effects and is favored predominantly by steric and conjugation effects. |
dc.description.sponsorship |
A.V.B. and Yu.F.S. are grateful to the Ministry of Education and
Science of Russia (State Contracts N 14.B25.31.0013) for financial
support. S.A.Sh. thanks the Russian Foundation for Basic Research
(Grant 14-03-0023-a). I.A., S.O.W., and N.R.J. thank the Icelandic
Centre for Research (RANNIS) for financial support, Grants No
080038021 and 100040022. R.B. acknowledges support from the
Icelandic Research Fund, grant no. 141218051. |
dc.format.extent |
149-156 |
dc.language.iso |
en |
dc.publisher |
Elsevier BV |
dc.relation.ispartofseries |
Journal of Molecular Structure;1132 |
dc.rights |
info:eu-repo/semantics/openAccess |
dc.subject |
Silacyclohexane |
dc.subject |
Molecular structure |
dc.subject |
Gas electron diffraction |
dc.subject |
Dynamic NMR spectroscopy |
dc.subject |
Quantum chemical calculations |
dc.subject |
Conformational analysis |
dc.subject |
Spectroscopy |
dc.subject |
Sameindir |
dc.subject |
Rafeindir |
dc.subject |
Ólífræn efnafræði |
dc.title |
Conformational properties of 1-cyano-1-silacyclohexane, C5H10SiHCN: Gas electron diffraction, low-temperature NMR and quantum chemical calculations |
dc.type |
info:eu-repo/semantics/article |
dcterms.license |
© 2016 Elsevier B.V. All rights reserved. |
dc.identifier.journal |
Journal of Molecular Structure |
dc.identifier.doi |
10.1016/j.molstruc.2016.10.012 |
dc.contributor.department |
Raunvísindastofnun (HÍ) |
dc.contributor.department |
Science Institute (UI) |
dc.contributor.school |
Verkfræði- og náttúruvísindasvið (HÍ) |
dc.contributor.school |
School of Engineering and Natural Sciences (UI) |