Details
| Original language | English |
|---|---|
| Pages (from-to) | 9804-9811 |
| Number of pages | 8 |
| Journal | Chemistry - a European journal |
| Volume | 22 |
| Issue number | 28 |
| Publication status | Published - 1 Jul 2016 |
Abstract
Previous ambiguities in the conformational and structural landscape of the volatile anesthetic enflurane have been solved combining microwave spectroscopy in a jet expansion and ab initio calculations. The broadband (2–18 GHz) rotational spectra identified three different rotamers, sharing a common trans ether skeleton but differing in the ±gauche/trans position of the terminal chlorine atom. For each chlorine conformation two different gauche orientations were predicted for the opposite difluoromethyl group, but only one is experimentally observable due to collisional relaxation in the jet. The experimental dataset comprised nine different isotopologues (35Cl,37Cl,13C) and a large number (>6500) of rotational transitions. The inertial data provided structural information using the substitution and effective procedures. The structural preferences were rationalized with additional ab initio, natural-bond-orbital and non-covalent-interaction analysis, which suggest that plausible anomeric effects at the difluoromethyl group could be overridden by other intramolecular effects. The difluoromethyl orientation thus reflects a minimization of inter-fluorine repulsions while maximizing F⋅⋅⋅H attractive interactions. A comparison with previous electron diffraction and spectroscopic data in the gas and condensed phases finally resulted in a comprehensive description of this ether, completing a rotational description of the most common multi-halogenated anesthetics.
Keywords
- ab initio calculations, halogenated ethers, rotational spectroscopy, supersonic jets, volatile anesthetics
ASJC Scopus subject areas
- Chemical Engineering(all)
- Catalysis
- Chemistry(all)
- Organic Chemistry
Cite this
- Standard
- Harvard
- Apa
- Vancouver
- BibTeX
- RIS
In: Chemistry - a European journal, Vol. 22, No. 28, 01.07.2016, p. 9804-9811.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - The Conformational Map of Volatile Anesthetics
T2 - Enflurane Revisited
AU - Pérez, Cristóbal
AU - Caballero-Mancebo, Elena
AU - Lesarri, Alberto
AU - Cocinero, Emilio J.
AU - Alkorta, Ibon
AU - Suenram, Richard D.
AU - Grabow, Jens Uwe
AU - Pate, Brooks H.
N1 - Funding Information: We thank the US National Science Foundation (NSF CHE-00960074), the Spanish MINECO (CTQ2014-54464-R, CTQ2015-68148-C2–2-P and CTQ2015-63997-C2-2-P), Comunidad Autónoma de Madrid (S2013/MIT-2841, Fotocarbon), the Deutsche Forschungsgemeinschaft (DFG) and the Land Niedersachsen for research funds. R.D.S. thanks Jerry Fraser at NIST for experimental support. E.J.C. thanks the MINECO for a “Ramón y Cajal” contract.
PY - 2016/7/1
Y1 - 2016/7/1
N2 - Previous ambiguities in the conformational and structural landscape of the volatile anesthetic enflurane have been solved combining microwave spectroscopy in a jet expansion and ab initio calculations. The broadband (2–18 GHz) rotational spectra identified three different rotamers, sharing a common trans ether skeleton but differing in the ±gauche/trans position of the terminal chlorine atom. For each chlorine conformation two different gauche orientations were predicted for the opposite difluoromethyl group, but only one is experimentally observable due to collisional relaxation in the jet. The experimental dataset comprised nine different isotopologues (35Cl,37Cl,13C) and a large number (>6500) of rotational transitions. The inertial data provided structural information using the substitution and effective procedures. The structural preferences were rationalized with additional ab initio, natural-bond-orbital and non-covalent-interaction analysis, which suggest that plausible anomeric effects at the difluoromethyl group could be overridden by other intramolecular effects. The difluoromethyl orientation thus reflects a minimization of inter-fluorine repulsions while maximizing F⋅⋅⋅H attractive interactions. A comparison with previous electron diffraction and spectroscopic data in the gas and condensed phases finally resulted in a comprehensive description of this ether, completing a rotational description of the most common multi-halogenated anesthetics.
AB - Previous ambiguities in the conformational and structural landscape of the volatile anesthetic enflurane have been solved combining microwave spectroscopy in a jet expansion and ab initio calculations. The broadband (2–18 GHz) rotational spectra identified three different rotamers, sharing a common trans ether skeleton but differing in the ±gauche/trans position of the terminal chlorine atom. For each chlorine conformation two different gauche orientations were predicted for the opposite difluoromethyl group, but only one is experimentally observable due to collisional relaxation in the jet. The experimental dataset comprised nine different isotopologues (35Cl,37Cl,13C) and a large number (>6500) of rotational transitions. The inertial data provided structural information using the substitution and effective procedures. The structural preferences were rationalized with additional ab initio, natural-bond-orbital and non-covalent-interaction analysis, which suggest that plausible anomeric effects at the difluoromethyl group could be overridden by other intramolecular effects. The difluoromethyl orientation thus reflects a minimization of inter-fluorine repulsions while maximizing F⋅⋅⋅H attractive interactions. A comparison with previous electron diffraction and spectroscopic data in the gas and condensed phases finally resulted in a comprehensive description of this ether, completing a rotational description of the most common multi-halogenated anesthetics.
KW - ab initio calculations
KW - halogenated ethers
KW - rotational spectroscopy
KW - supersonic jets
KW - volatile anesthetics
UR - http://www.scopus.com/inward/record.url?scp=84973353630&partnerID=8YFLogxK
U2 - 10.1002/chem.201601201
DO - 10.1002/chem.201601201
M3 - Article
AN - SCOPUS:84973353630
VL - 22
SP - 9804
EP - 9811
JO - Chemistry - a European journal
JF - Chemistry - a European journal
SN - 0947-6539
IS - 28
ER -