Electron Resonance Studies of Perchlorodiphenylmethyl and Perchlorotriphenylmethyl Free Radicals

摘要

The stable free radicals perchlorodiphenylmethyl, (C6Cl5)2Cdot;Cl, and perchlorotriphenylmethyl, (C6Cl5)3C, have been examined by electron resonance. In solution, the isotropicagr;hyphen;chlorine hyperfine splitting in PDM was found to be 6.08 Mc/sec. Splittings from13C in natural abundance at the methyl carbon (about 100 Mc/sec) and at additional phenylndash;carbon sites were measured for both radicals. By incorporating PDM in the liquid crystalphyphen;azoxyanisole, the principal values of the anisotropic hyperfine coupling tensor of theagr;chlorine were derived and found to beA11thinsp;equals;thinsp;minus;thinsp;9.2,A22thinsp;equals;thinsp;minus;thinsp;18.9, andA33thinsp;equals;thinsp;47.2Mcsol;sec. The variation with temperature of the degree of ordering of the radicals in the nematic mesophase was determined.