From Weak to Strong Antiferromagnetism: Tuning the Magnetic Properties of a Mononuclear Fe<sup>3+</sup> Complex via Electron Transfer Photochromism
Dong‐Xue Feng, Wuji Wei, Qi Li, Qian Zhang, Ji‐Xiang Hu, Guo‐Ming Wang, Jinhua Li
Abstract
Photomagnetic materials have attracted enormous attention due to the adjustable coloration and magnetization via light irradiation, while challenges still exist for drastically tuning the magnetism at room temperature. Herein, a novel multifunctional crystal complex (H3-TPB)[Fe(C2O4)3]·H2O (1; C2O42– = oxalate and TPB = 1,3,5-tris(4-pyridyl)benzene) is constructed by self-assembly of paramagnetic Fe3+ ions, electron donor oxalate, and electron acceptor TPB ligands. After light irradiation, the compound 1 undergoes unidirectional electron transfer (ET) from oxalate to TPB ligands and Fe3+ ions, which not only results in the decomposition of oxalate and generation of radicals and Fe2+ species but also leads to remarkable ET-triggered photochromism. Importantly, room temperature light irradiation changes the magnetic behavior of 1 from weak to strong antiferromagnetism. Moreover, thanks to the stability of the photogenerated radicals, the photoresponsive proton conductivity property for 1 is also explored and photoenhanced proton conductivity is observed after photoirradiation.