Approach of Studies on Magnetic Properties of a 3-Armed Nonconjugated Radical Macromolecule*

Nonconjugated radical polymers (i.e., macromolecules with aliphatic backbones possessing stable open-shell sites on their pendant groups) have arisen as an intriguing complement to π-conjugated polymers in organic electronic applications, due to their low optical density and easy-tunable structure. Moreover, conjugated dendritic macromolecules have shown significant promise in terms of their response under magnetic fields; however, the molecular design of nonconjugated radical polymers has focused on linear polymers. Therefore, we have synthesized a 3-armed nonconjugated radical macromolecule through a single step reaction and evaluated the electronic and magnetic behavior in both experimental and computational approach. The conductivity value of this macromolecule is on par with many previous linear radical polymers. Additionally, this macromolecule showed shifting magnetic behavior from paramagnetic (300 K) to antiferromagnetic (5 K) at low temperatures due to local ordering. Computational predictions support tighter packing of nitroxides groups for higher-generation dendrimers, which promotes enhanced spin interactions. Thus, this dendritic radical macromolecule affords a promising, high-performance system for the next generation of dendrimers of this type.