Polarographic investigation of electron donor–acceptor complexes

Using a computer-controlled precision polarograph the formation constants of electron donor–acceptor (EDA) complexes formed from aromatic hydrocarbons and nitrofluorene derivatives have been determined in acetonitrile. The EDA interactions are of the same magnitude in this solvent as in less polar solvents. The strength of the complexes is related to the reduction potential (or electron affinity) of the acceptors and the size of the π system of the donors. Spectra of the complexes were computed from spectra of mixtures of accepter and donor with the help of the polarographic data. No relationship between the molar absorptivity of the charge-transfer band and the formation constant was apparent from these spectra.