Octacyanidotungstate(IV) Coordination Chains Demonstrate a Light-Induced Excited Spin State Trapping Behavior and Magnetic Exchange Photoswitching.

A huge increase in the magnetization of two coordination chains based on tetravalent octacyanidometalates (W and Mo ) is observed on irradiation with 436 nm light, while no such behavior is observed for the Nb analogue. A photomagnetic response based solely on [W (CN) ] is demonstrated for the first time. The observed behavior is attributed to the light-induced excited spin state trapping (LIESST) effect at the octacyanidometalate, and to the resulting magnetic exchange ON/OFF photoswitching between the Mn center and the photoinduced high-spin (S=1) W or Mo centers.