Reversible light-induced spin state switching in a dinuclear Fe(ii) spin crossover complex

Abstract

A dinuclear Fe(II) spin crossover (SCO) complex with the formula [Fe₂L₅(NCS)₄]·2DMF·2H₂O (1) was synthesised from 1-naphthylimino-1,2,4-triazole (L). Complex 1 exhibits an incomplete thermally induced spin transition with a transition temperature T_1/2 of 95 K and a thermally trapped metastable high-spin state at low temperatures. Furthermore, it undergoes a reversible light-induced spin crossover by alternate irradiation with 532 and 808 nm lasers.