Potential energy surface of fluoroxene: experiment and theory

Abstract

The potential energy surface (PES) of the general anesthetic fluoroxene (2,2,2-trifluoroethyl vinyl ether) was probed in a supersonic jet expansion using broadband chirped-pulse Fourier transform microwave (CP-FTMW) spectroscopy and theoretical calculations. The PES is dominated by a single conformation, as other stable minima are shown to kinetically relax in the expansion to the global minimum. Consistently, the rotational spectrum reveals a single conformation. Fluoroxene adopts a C_S heavy-atom planar skeleton structure in the gas phase, with a cis–trans conformation (cis for the CH₂CH–O–CH₂– and trans for the CH–O–CH₂–CF₃ part). The sensitivity of a recently-built CP-FTMW spectrometer at the UPV/EHU is demonstrated by the detection of five isotopologues of fluoroxene in natural abundance, corresponding to the ¹³C and ¹⁸O monosubstituted species. The r_S and r₀ structures were determined and are in good agreement with theoretical predictions using the MP2, B3LYP and M06-2X methods.