Diffuse Reflection Spectra of Some Würster Salts

Nine Würster salts derived from p-phenylenediamine, benzidine, and their N-methyl derivatives were examined for diffuse reflection spectra and classified into three groups, namely, those showing a strong charge-transfer band similar to that in the solution’s dimer spectrum, those showing a strong α-band characteristic of the monomer and a relatively weak charge-transfer band, and, finally, those showing a spectrum which bears no resemblance to either the monomer or dimer spectrum. The mode of intermolecular interaction in these cation-radical salts was speculated upon on the basis of the spectra and the magnetic susceptibilities.