1. F. Ramirez and N. McElvie, J. Am. Chem. Soc. 79, 5829 (1957).
2. (a) W. G. Bentrude, in Free Radicals, Vol. 2, J. K. Kochi, ed., Wiley-Interscience, New York (1973), Chap. 22. (b) K. U. Ingold and B. P. Roberts, Free-Radical Substitution Reactions, Interscience, New York (1971), pp. 116-133. (c) W. G. Bentrude, Ann. Rev. Phys. Chem. 18, 283 (1967). (d) C. Walling and M. S. Pearson, Top. Phosphorus Chem. 3, 1, (1966). (e) P. Schipper, E. H. J. M. Janzen, and H. M. Buck, Top. Phosphorus Chem. 9, 407 (1977) (esr emphasis), (f) D. G. Pobedimskii, M. A. Mukmeneva, and P. A. Kirpidinikov, Russ. Chem. Rev. 41, 555 (1972). (g) J. R. Morton and K. F. Preston in Landolt-Bornstein, New Series, Vol. II/9a, H. Fischer and K.-H. Hellwege, Eds., Springer-Verlag; Berlin, 1977. A. G. Davies and B. P. Roberts in Landolt-Bornstein, New Series, Vol. II/9c, H. Fischer and K.-H. Hellwege, Eds., Springer-Verlag; Berlin, 1979. (Compilations of esr data for phosphoranyl radicals.)
3. (a) W. G. Bentrude, in Organic Free Radicals, W. A. Pryor, ed., ACS Symposium Series, No. 69, American Chemical Society, Washington, D.C. (1978), Chap. 20. (b) W. G. Bentrude, Phosphorus Sulfur
3, 109 (1977).
4. B. P. Roberts, in Advances in Free Radical Chemistry, Vol. 6, G. H. Williams, ed., Heyden and Sons, London (1980).
5. C. Walling and R. Rabinowitz, J. Am. Chem. Soc. 81, 1243 (1959).