A Paramagnetic Resonance Study of Unhindered Biphenyl Anion Radicals (III)

The radical anions of biphenyl and some of its bridged derivatives have been studied by e.s.r. It is found that the proton hyperfine coupling constants change monotonically through the series of radical anions derived from biphenyl, 9,10-dihydrophenanthrene, fluorene, dibenzothiophene, and dibenzofuran. Deuterations have been carried out for the latter two compounds and the hyperfine coupling constants are assigned to specific positions in these anions. The data are displayed in the form of a correlation diagram from which assignments for other bridged biphenyl anions can be made.