High-Spin Polymers: Ferromagnetic Coupling of S = 1 Hexaazacyclophane Units up to a Pure S = 2 Polycyclophane.

Triarylamines oxidized to radical cations can be used as stable spins sources for the design of high-spin compounds. Here, we present the synthesis of the polyarylamine-containing hexaazacyclophanes linked via meta-terphenyl bridges. Spins, created after oxidation of the polymer, can be coupled magnetically in cyclophane moieties via meta-phenyl and along the polymer chain via meta-terphenyl units. The formation of a quintet spin state was evidenced by pulsed-EPR nutation spectroscopy. Two exchange coupling constants via both couplers were determined experimentally and corresponded to J/k = 89 K in the cyclophane moiety and j/k = 17 K via meta-terphenyl. Most importantly, in this polymer, four spins can be ferromagnetically ordered via both couplers, which leads to the high spin state. [ABSTRACT FROM AUTHOR]