Magnetic Bistability and Thermochromism in a Molecular CuII Chain

An original magnetic bistability and a thermochromic transition are observed in a new CuII molecular chain. Thermal structural studies reveal changes in the CuII coordination sphere, driven by a more pronounced Jahn−Teller effect at low temperature. These distortions provoke a gradual color change. The structural study at 10 K shows a dimerization of the molecular chain, in agreement with the abrupt magnetic transition observed at 30 K.