Conformation of perfluoroalkyl radicals in the solid phase - I. Terminal similar to CF2 center dot CF2 radical stabilized at 77 K matrices of linear perfluoroalkanes and polytetrafluoroethylene

An equilibrium conformation of the perfluoroalkyl similar to CF2. CF2 radic al at 77 K in matrices of polytetrafluoroethylene and n-perfluoroalkanes wa s studied. Upon cooling from 300 to 77 K at temperatures below 200 K, the E SR spectrum of this radical changes, and the well-resolved hyperfine struct ure appears. The hyperfine splitting constants on nuclei of two nonequivale nt F-beta atoms were determined: 2.2 and 1.1 mT, respectively. The A(parall el to) and A(perpendicular to) values for the F alpha atoms are 22.5; and 3 .3 mT, respectively.The conformational angle between the axis of the orbita l of an unpaired electron and projection of the C-beta-C-gamma bond is 5.6 degrees.