A long-lived photo-induced metastable state of linkage isomerization accompanied with a spin transitionElectronic supplementary information (ESI) available: Experimental details for FTIR, magnetic measurement and photocrystallography, additional figures of photomagnetism and photocrystallography, and X-ray crystallographic data. CCDC 843267-843270. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c2cc31326j

In addition to the generally observed LIESST phenomenon, polymorph D of trans -[Fe II (abpt) 2 (NCS) 2 ] exhibits a long-lived photo-induced metastable state through linkage isomerization accompanied with a spin crossover transition, which is stable up to 108 K. In addition to the generally observed LIESST phenomenon in iron( ii ) spin crossover complexes, a long-lived photo-induced metastable state was found through a thiocyanate linkage isomerization under 532 nm laser irradiation. The process is accompanied by a spin crossover on the iron( ii ) center and the metastable form is stable up to 108 K.