Observation of slow magnetic relaxation phenomena in spatially isolated pi-radical ions

The use of molecular spins as quantum bits is fascinating because it offers a wide range of strategies through chemical modifications. In this regard, it is very interesting to search for organic radical ions that have small spin-orbit coupling values. On the other hand, the feature of the magnetic relaxation of pi-organic radical ions is rarely exploited due to the difficulty of spin dilution, and pi-stacking interaction. In this study, we focus on N,N ',N ''-tris(2,6-dimethylphenyl)benzenetriimide (BTI-xy), where three xylene moieties connected to the imide groups cover the pi-plane of the BTI core. As a result, BTI-xy radical anions without pi-stacking interaction were obtained. This led to the slow magnetization relaxation, which is reported for the first time in organic radicals. Furthermore, the relaxation times in a solution state revealed the importance of spin interaction.