Axial and equatorial cyclohexylacyl and tetrahydropyranyl-2-acyl radicals. An experimental and theoretical study.
Axial and equatorial cyclohexylacyl and tetrahydropyranyl-2-acyl radicals gave distinct EPR spectra thanks to surprisingly large beta-hydrogen atom hyperfine splittings that enabled them to be characterized and monitored. DFT computations indicated that the axial species (X = CH(2)) had a higher barrier to rotation about the (O)C(alpha)-C(beta) bond. The computed difference Delta H degrees for the axial and equatorial radicals (R = H, X = CH(2)) was 0.8 kcal mol(-)(1).
DiLabio
Gino A
GA
National Institute for Nanotechnology, National Research Council of Canada, W6-010 ECERF, 9107 116th Street, Edmonton, AB, Canada T6G 2V4.
Ingold
Keith U
KU
Roydhouse
Mark D
MD
Walton
John C
JC