Asymmetric redox reactions of C3-symmetric starburst compound with six arylamines

The redox behavior of the titled species, arranged concentrically with three inner arylamines and three outer ones, was examined voltammetrically and electrospectroscopically in order to obtain the redox interaction between six redox active phenylamines. Our attention was paid to whether the nearly C3-symmetric species showed the symmetric or the asymmetric multi-redox reactions The steady-state voltammogram at a microelectrode exhibited asymmetric features of three waves of which oxidation currents had the ratio of 1:3:6. These numbers of the electrons transferred, n, were confirmed with the analysis of the Cottrell plots with non-zero intercept. Visible spectra for n = 1 and 3 showed intervalence bands. The voltammetric asymmetry was explained in terms of four interaction energies between N and N+ and between N+ and N+ through a phenyl group at the meta- and the para-positions. The n vs. E curve calculated statistic mechanically for adequate values of the interaction energy agreed with the experimental one. The most stable chemical structure of an mixed-valence species at each n was suggested, for example, one two N+s in the inner arylamines and one N+ in the outer ones for n = 3.