Bis-trifluoromethyl effect: doubled transitions in the rotational spectra of hexafluoroisobutene, (CF3)2C═CH2.
Rotational spectra for hexafluoroisobutene, and its (13)C isotopologues, have been recorded between 8 and 16 GHz using a chirped pulse, Fourier transform microwave spectrometer. Notably, all spectra observed are doubled with separations between the doublets being between 1 and 60 MHz. We propose that the bis-trifluoromethyl groups of the target molecule are staggered in the equilibrium configuration, and that a novel, out-of-phase rotation through a F-CCC-F planar configuration with low barrier (<100 cm(-1)), leads to the observed doubled rotational spectra.
Department of Chemistry, Wesleyan University, Hall-Atwater Laboratories, 52 Lawn Avenue, Middletown, Connecticut 06459-0180, USA.
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GS
Grubbs
Stewart E
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Novick
Wallace C
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Pringle
Jaan
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Laane
Esther J
EJ
Ocola
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Cooke