Magnetic Coupling in the Fullerene Dimer {Co(Ph3P)(C6H5CN)}2(μ2‑η2:η2‑C60)2 with Two Zerovalent Cobalt Atoms as Bridges

The magnetic metal-bridged fullerene dimer {Co­(Ph3P)­(C6H5CN)}2(μ2-η2,η2-C60)2 was synthesized for the first time and studied by X-ray crystallography and magnetic susceptibility methods. The dimers, in which two fullerene C60 cages are η2-bonded through two Co0 atoms (S = 1/2), have a triplet (S = 1) state and transfer to a diamagnetic singlet (S = 0) ground state below 50 K (J/kB = −28.6 K). The theoretical calculations show that C60 can work as an efficient spin coupler between paramagnetic metals.

本研究首次合成了磁性金属桥联富勒烯（fullerene）二聚体{Co(Ph3P)(C6H5CN)}2(μ2-η2,η2-C60)2，并通过X射线晶体学（X-ray crystallography）与磁化率（magnetic susceptibility）方法对其开展了表征研究。该二聚体中，两个C60富勒烯笼通过两个零价钴（Co⁰）原子以η2配位键结合，每个钴原子的自旋量子数S=1/2；整体呈现自旋三重态（S=1），当温度低于50 K时会转变为反磁性单重态（S=0）基态，其磁交换耦合常数J/kB为-28.6 K。理论计算结果表明，C60可作为顺磁性金属之间的高效自旋耦合体（spin coupler）。