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 subset of[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 subset of[12]CPP and pristine Y2@C79N were comparatively investigated in carbon disulfide and in solid state, and it was found that the Y2@C79N subset of[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.

Automated summary

In this study, we demonstrate the spin modulation of Y2@C79N by host-guest interaction with a carbon nanoring of [12]Cycloparaphenylene ([12]CPP). The adjustable EPR signals of Y2@C79N subset of [12]CPP were observed, indicating the significant effect of host-guest interaction on the spin and paramagnetic property of hooped Y2@C79N. The [12]CPP host induced the orientation of the Y2@C79N guest, which led to enhanced spin-nuclei couplings compared to pristine Y2@C79N.