Tuning of Ferromagnetic Spin Interactions in Polymeric Aromatic Amines via Modification of Their π‑Conjugated System

Polyarylamine containing meta–para–para-aniline units in the main chain and meta–para-aniline units in the pendant chains was synthesized. The polymer
can be oxidized to radical cations in chemical or electrochemical
ways. The presence of meta-phenylenes in the polymer
chemical structure allows for the ferromagnetic coupling of electronic
spins, which leads to the formation of high spin states. Detailed
pulsed-EPR study indicates that the S = 2 spin state
was reached for the best oxidation level. Quantitative magnetization
measurements reveal that the doped polymer contains mainly S = 2 spin states and a fraction of S =
3/2 spin states. The efficiency of the oxidation was determined to
be 74%. To the best of our knowledge, this polymer is the first example
of a linear doped polyarylamine combining such high spin states with
high doping efficiency.