Enhanced Spin-Nuclei Couplings of Paramagnetic Azametallofullerene Hooped in Cycloparaphenylene

Azametallofullerene Y₂@C₇₉N has outstanding electron spin characteristics with potential application in the fields of magnetoreception system and precision measurement as a molecular spin probe. Herein, we report the spin modulation of Y₂@C₇₉N by means of host-guest interaction with a carbon nanoring of [12]Cycloparaphenylene ([12]CPP). By means of temperature-dependent electron paramagnetic resonance (EPR) measurements, the adjustable EPR signals of Y₂@C₇₉N⊂[12]CPP were observed, revealing the great effect of host-guest interaction on the spin and paramagnetic property of hooped Y₂@C₇₉N. The EPR signals of Y₂@C₇₉N⊂[12]CPP and pristine Y₂@C₇₉N were comparatively investigated in carbon disulfide and in solid state, and it was found that the Y₂@C₇₉N⊂[12]CPP complex exhibits enhanced spin-nuclei couplings compared to those of pristine Y₂@C₇₉N. We propose that the [12]CPP host can induce the orientation of the Y₂@C₇₉N guest, and consequently change the spin-nuclei couplings of Y₂@C₇₉N. This study would promote the creation of new molecular spin materials.