Abstract The effect of substituents in the aromatic ring on the half-wave potentials of the polarographic reduction of (t-butyl phenyl ketone)-and (methyl benzoate)- tricarbonylchromiums in dimethylformamide have been studied. The Hammett relationship is satisfactorily obeyed for both series of compounds, and the ϱ values are practically equal to those measured for the analogous uncomplexed substrates. The results are interpreted in ...