| Summary: | Aiming at constructing photoresponsive spin crossover (SCO) behavior, herein we designed a new ligand Abtz (Abtz = (<i>E</i>)-<i>N</i>-(4-((<i>E</i>)-phenyldiazenyl)phenyl)-1-(thiazol-4-yl)methanimine) which was decorated by a photochromic azobenzene group. Based on this photochromic ligand, a mononuclear Fe(II) SCO molecule [Fe(Abtz)<sub>3</sub>](BF<sub>4</sub>)<sub>2</sub>·(EAC)<sub>2</sub> (<b>1</b>, EAC = ethyl acetate) was successfully synthesized and showed a complete one-step SCO behavior. Under continuous UV light and blue-light exposure, the <i>cis–trans</i> photoisomerization of both ligand Abtz and compound <b>1</b> in the liquid phase was confirmed through UV–Vis spectra. Moreover, the <sup>1</sup>H-NMR spectra of Abtz reveal a <i>trans–cis</i> conversion ratio of 37%. Although the UV–Vis spectra reveal the photochromic behavior for <b>1</b> in the solution phase, the SCO behavior in the liquid state is absent according to the variable-temperature Evans method, suggesting the possible decomposition. Moreover, in the solid state, the <i>cis–trans</i> photoisomerization of both Abtz and <b>1</b> was not observed, due to the steric hindrance.
|
|---|