Exchange-Biased Dimers of Single-Molecule Magnets in OFF and ON States

A new Fe9 single-molecule magnet has been synthesized and found to crystallize as head-to-head dimers. Two-thirds of these are exchange-coupled through a hydrogen-bond, whereas the other third of the dimers are noninteracting, as monitored by magnetization hysteresis measurements. The crystal thus contains a mixture of ON and OFF dimers with respect to the quantum mechanical coupling through the hydrogen-bond.