Slow Magnetic Relaxation and Spin-Crossover Behavior in a Bicomponent Ion-Pair Cobalt(II) Complex

A bicomponent ion-pair molecule compound [Co(Brphterpy)(2)][Co(NCS)(4)]center dot 2MeCN was designed and prepared for the construction of multistable functional materials. Due to the different coordination geometries of the cationic and anionic Co-II ions, this compound exhibits both thermally induced spin crossover (SCO) and field-induced single-ion magnetism (SIM). This represents a rare example of a two-component system with the coexistence of SIM and SCO behaviors and suggests a simple, yet very efficient strategy for the construction of multistable molecular materials.