Synthesis, Structure, and Optical‐response Magnetic Property of a Heteroarene‐azo Functionalized Mn19 Cluster.

Comprehensive Summary: Metal clusters with photoswitching ligands can undergo magnetic changes under light radiation, which makes them potential optical‐response magnetic‐switching materials. Herein, a photoswitchable Mn‐oxo cluster [MnII15MnIII4(L)18(OH)12(N3)6] (ClO4)2 (C6H5CN)8, (Mn19azo, HL=1‐(hydroxymethyl)‐3,5‐dimethyl‐4‐(phenyldiazenyl)‐pyrazole) has been designed and synthesized to realize the photoswitching behavior. Mn19azo shows quick trans‐to‐cis transformation upon 365 nm light irradiation in CH2Cl2 solution and solid state as confirmed by UV‐Vis spectra. After the powder sample was irradiated for 80 min, the Curie constant of Mn19azo increases by about 7%. The change of magnetic properties can be considered as the result of the change of intermolecular interactions. [ABSTRACT FROM AUTHOR]