Electron spin resonance spectra of triple ions: anisotropic effects in the hyperfine splitting patterns of 23Na counter-ions

The formation, in tetrahydrofuran, of triple ions of the formula Na2Q+ (Q = p-benzosemiquinone, 2,3-, 2,5-, 2,6-dimethyl-p-benzosemiquinone, durosemiquinone) has been detected by electron spin resonance spectroscopy. The spectra show asymmetric broadening within the 23Na hyperfine multiplets. From the direction of this broadening, it is deduced that the sodium ions lie in the plane of the semiquinone anion, one sodium ion associating with each oxygen.