Amination of Gd@C82 endohedral fullerene: tunable substitution effect on quantum coherence behaviors

The core-shell structure of endohedral fullerenes based anisotropic magnetic molecules of high spin with long coherence time could help scale up the quantum system. In this research, by aminating Gd@C82 with morpholine, three derivatives are functionalized with 5, 7 and 9 morpholine groups providing an interesting model to investigate the relationship between the quantum coherence and spin environment. The original radical locating on the carbon cage is successfully quenched, affording the quantum phase memory time (TM) over 5 μs at 5 K. By increasing the number of substitution groups, spin-lattice relaxation times (T1) also show significant enhancement due to the interaction variation between the molecules and environment. We found the TM of the three molecules shows no obviously difference below 10 K, while it is limited by T1 at higher temperature. In this work, the variable function groups are able to tune both T1 and TM, offering the possibility to apply the high-spin magnetic molecules in the field of quantum information processing.