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)(mu(2)-eta(2),eta(2)-C-60)(2) was synthesized for the first time and studied by X-ray crystallography and magnetic susceptibility methods. The dimers, in which two fullerene C-60 cages are eta(2)-bonded through two Co-0 atoms (S = 1/2), have a triplet (S = 1) state and transfer to a diamagnetic singlet (S = 0) ground state below 50 K (J/k(B) = 28.6 K). The theoretical calculations show that C-60 can work as an efficient spin coupler between paramagnetic metals.