Magnetic coupling switch by means of host–guest chemistry in a polyether side-arm

Complexation from the polyether ligand (LH2), Ni(CH3CO2)2, and Ba(CF3SO3)2 gave BaNiL·2CF3SO3, which showed ferromagnetic coupling ascribable to the dimer structure determined by means of X-ray crystallographic analysis. After removal of Ba2+ by treatment with guanidinium sulfate, NiL was isolated as an empty host, which did not show ferromagnetic coupling.