Abrupt spin transition around room temperature and light induced properties in FeII complexes with N4O2 coordination sphere

Mononuclear spin-crossover complex FeII(L)2·CH3OH (1·CH3OH) and its desolvated product 1 exhibit abrupt spin transitions around room temperature. 1 also shows a light induced excited spin state trapping (LIESST) effect and a light induced thermal hysteresis (LITH) phenomenon at low temperature.