text: Electron transfer self-exchange rates can be also determined with the experimental value of line-width and chemical shift. Sharp peaks of diamagnetic compounds can be broadened during the electron transfer with its partner paramagnetic compound (one-electron oxidized species), since paramagnetic compounds exhibit broader peaks at a different chemical shift. If their self-exchange rate is sufficiently faster than the NMR timescale, the line-broadening of the peaks is observed at shifted chemical shifts in the spectrum. In order to determine the self-exchange rate of sample compounds, one can choose a certain characteristic peak of the sample diamagnetic compound, and examine the peak broadening in the mixture with its partner paramagnetic compound. The broadened line-widths are proportional to mole fraction, and the equation can be used to determine self-exchange rate with the value of mole fraction, chemical shift and line-width: , is the rate constant of electron transfer self-exchange,  and  are the mole fractions of diamagnetic and paramagnetic compounds,  is the chemical shift difference (in Hz) between pure diamagnetic and paramagnetic compounds, and  is the half-width of the peak (width at half height) of the selected peak.  and are the peak widths of the pure diamagnetic and paramagnetic species, and  is the total concentration of the exchanging species in M (mol/L).
  For more accurate calculation of each mole fraction, the following equations can be used;   , is a shifted chemical shift of the selected peak, and  is the original chemical shift of the diamagnetic species based on the assumption that the change in chemical shift is linearly correlated to the mole fraction of the paramagnetic species.