Details
| Original language | English |
|---|---|
| Pages (from-to) | 1383-1393 |
| Number of pages | 11 |
| Journal | Zeitschrift fur Physikalische Chemie |
| Volume | 234 |
| Issue number | 7-9 |
| Early online date | 30 Jun 2020 |
| Publication status | Published - 27 Aug 2020 |
Abstract
High-resolution rotational spectroscopy was used to investigate the conformational landscape of methyl-3,3,3-trifluoropyruvate, a small, partially-fluorinated molecule, which is of interest because of its chemical properties and reactivity in contrast to the unfluorinated species. Methyl 3,3,3-trifluoropyruvate is also subject to two possible large amplitude motions of the methyl and trifluoromethyl group. However, only the methyl rotor gives rise to the tunneling splitting specific to individual conformers. In the rotational spectrum measured in the frequency region from 6 to 27 GHz, the identified conformers, s-cis and s-trans, were fitted to experimental accuracy, resulting in the accurate determination of the vibrational ground state rotational constants A 0 = 2185.05827 36 MHz ${A}_{0}=2185.05827\left(36\right)\text{\hspace{0.17em}MHz}$, B 0 = 1023.300 31 17 MHz ${B}_{0}=1023.30031\left(17\right)\text{\hspace{0.17em}MHz}$, and C 0 = 803.520287 95 MHz ${C}_{0}=803.520287\left(95\right)\text{\hspace{0.17em}MHz}$ for the s-cis conformer, and A 0 = 2706.9024 (49) MHz ${A}_{0}=2706.9024\left(49\right)\text{\hspace{0.17em}MHz}$, B 0 = 864.889 539 (81) MHz ${B}_{0}=864.889539\left(81\right)\text{\hspace{0.17em}MHz}$, and C 0 = 746.532 896 (71) MHz ${C}_{0}=746.532896\left(71\right)\text{\hspace{0.17em}MHz}$ for the s-trans conformer. Additionally the barrier heights of the methyl rotor V 3 CH 3 = 363. 116 94 cm-1 ${V}_{3}\left({\text{CH}}_{3}\right)=363.116\left(94\right){\text{\hspace{0.17em}cm}}^{-1}$ and V 3 (CH 3) = 389.290 (80) cm-1 ${V}_{3}\left({\text{CH}}_{3}\right)=389.290\left(80\right){\text{\hspace{0.17em}cm}}^{-1}$ were obtained for the s-cis and s-trans conformer, respectively.
Keywords
- inertial defect, internal rotation, large amplitude motion, methyl 3,3,3-trifluoropyruvate, microwave spectroscopy
ASJC Scopus subject areas
- Chemistry(all)
- Physical and Theoretical Chemistry
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In: Zeitschrift fur Physikalische Chemie, Vol. 234, No. 7-9, 27.08.2020, p. 1383-1393.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Barrier to internal rotation, symmetry and carbonyl reactivity in methyl 3,3,3-trifluoropyruvate
AU - Lengsfeld, Kevin Gregor
AU - Buschmann, Philipp
AU - Kats, Pavel
AU - Siekmann, Dirk
AU - Herbers, Sven
AU - Adam Obenchain, Daniel
AU - Genuit, Stefanie
AU - Höhne, Cara Marie
AU - Grabow, Jens Uwe
N1 - Funding Information: We wish to thank the Land Niedersachsen, the Deutsche Forschungsgemeinschaft, DAO wishes to thank the Alexander von Humboldt Foundation and KGL wishes to thank the Fonds der Chemischen Industrie for fellowship.
PY - 2020/8/27
Y1 - 2020/8/27
N2 - High-resolution rotational spectroscopy was used to investigate the conformational landscape of methyl-3,3,3-trifluoropyruvate, a small, partially-fluorinated molecule, which is of interest because of its chemical properties and reactivity in contrast to the unfluorinated species. Methyl 3,3,3-trifluoropyruvate is also subject to two possible large amplitude motions of the methyl and trifluoromethyl group. However, only the methyl rotor gives rise to the tunneling splitting specific to individual conformers. In the rotational spectrum measured in the frequency region from 6 to 27 GHz, the identified conformers, s-cis and s-trans, were fitted to experimental accuracy, resulting in the accurate determination of the vibrational ground state rotational constants A 0 = 2185.05827 36 MHz ${A}_{0}=2185.05827\left(36\right)\text{\hspace{0.17em}MHz}$, B 0 = 1023.300 31 17 MHz ${B}_{0}=1023.30031\left(17\right)\text{\hspace{0.17em}MHz}$, and C 0 = 803.520287 95 MHz ${C}_{0}=803.520287\left(95\right)\text{\hspace{0.17em}MHz}$ for the s-cis conformer, and A 0 = 2706.9024 (49) MHz ${A}_{0}=2706.9024\left(49\right)\text{\hspace{0.17em}MHz}$, B 0 = 864.889 539 (81) MHz ${B}_{0}=864.889539\left(81\right)\text{\hspace{0.17em}MHz}$, and C 0 = 746.532 896 (71) MHz ${C}_{0}=746.532896\left(71\right)\text{\hspace{0.17em}MHz}$ for the s-trans conformer. Additionally the barrier heights of the methyl rotor V 3 CH 3 = 363. 116 94 cm-1 ${V}_{3}\left({\text{CH}}_{3}\right)=363.116\left(94\right){\text{\hspace{0.17em}cm}}^{-1}$ and V 3 (CH 3) = 389.290 (80) cm-1 ${V}_{3}\left({\text{CH}}_{3}\right)=389.290\left(80\right){\text{\hspace{0.17em}cm}}^{-1}$ were obtained for the s-cis and s-trans conformer, respectively.
AB - High-resolution rotational spectroscopy was used to investigate the conformational landscape of methyl-3,3,3-trifluoropyruvate, a small, partially-fluorinated molecule, which is of interest because of its chemical properties and reactivity in contrast to the unfluorinated species. Methyl 3,3,3-trifluoropyruvate is also subject to two possible large amplitude motions of the methyl and trifluoromethyl group. However, only the methyl rotor gives rise to the tunneling splitting specific to individual conformers. In the rotational spectrum measured in the frequency region from 6 to 27 GHz, the identified conformers, s-cis and s-trans, were fitted to experimental accuracy, resulting in the accurate determination of the vibrational ground state rotational constants A 0 = 2185.05827 36 MHz ${A}_{0}=2185.05827\left(36\right)\text{\hspace{0.17em}MHz}$, B 0 = 1023.300 31 17 MHz ${B}_{0}=1023.30031\left(17\right)\text{\hspace{0.17em}MHz}$, and C 0 = 803.520287 95 MHz ${C}_{0}=803.520287\left(95\right)\text{\hspace{0.17em}MHz}$ for the s-cis conformer, and A 0 = 2706.9024 (49) MHz ${A}_{0}=2706.9024\left(49\right)\text{\hspace{0.17em}MHz}$, B 0 = 864.889 539 (81) MHz ${B}_{0}=864.889539\left(81\right)\text{\hspace{0.17em}MHz}$, and C 0 = 746.532 896 (71) MHz ${C}_{0}=746.532896\left(71\right)\text{\hspace{0.17em}MHz}$ for the s-trans conformer. Additionally the barrier heights of the methyl rotor V 3 CH 3 = 363. 116 94 cm-1 ${V}_{3}\left({\text{CH}}_{3}\right)=363.116\left(94\right){\text{\hspace{0.17em}cm}}^{-1}$ and V 3 (CH 3) = 389.290 (80) cm-1 ${V}_{3}\left({\text{CH}}_{3}\right)=389.290\left(80\right){\text{\hspace{0.17em}cm}}^{-1}$ were obtained for the s-cis and s-trans conformer, respectively.
KW - inertial defect
KW - internal rotation
KW - large amplitude motion
KW - methyl 3,3,3-trifluoropyruvate
KW - microwave spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=85087936683&partnerID=8YFLogxK
U2 - 10.1515/zpch-2020-0008
DO - 10.1515/zpch-2020-0008
M3 - Article
AN - SCOPUS:85087936683
VL - 234
SP - 1383
EP - 1393
JO - Zeitschrift fur Physikalische Chemie
JF - Zeitschrift fur Physikalische Chemie
SN - 0942-9352
IS - 7-9
ER -