Photochromic Polynuclear Dysprosium Single‐Molecule Magnets With Anthracene‐9‐Carboxylate

ABSTRACT Photochromic dysprosium single‐molecule magnets (Dy‐SMMs) not only possess excellent intrinsic magnetic properties but also facilitate the preparation of intelligent devices owing to the integration of photochromism. However, related cases are still limited up to now. Herein, we report two photochromic polynuclear Dy‐SMMs, [Et 3 NH][Dy 4 (ana) 9 (OH) 4 (CH 3 CN) 2 (H 2 O)]·solvents ( 1 ; Hana = anthracene‐9‐carboxylatic acid) and [Et 3 NH] 2 [Dy 6 (Tox) 4 (aca) 12 (OH) 2 (CH 3 OH) 2 ]·solvents ( 2 ; Tox − = N ‐TEMPO oxamate ion). They have tetrahedral [Dy 4 (OH) 4 ] 12+ and double‐layered cage‐like [Dy 6 (Tox) 4 (OH) 2 ] 12+ cores, respectively, which are ligated by ana − ligands into tetra‐ and hexa‐nuclear cluster structures. Both 1 and 2 exhibit zero‐field single‐molecule magnet (SMM) behavior featuring a single magnetic relaxation process, which evolved into dual‐relaxation processes upon the application of external dc fields. They also exhibit expected photochromic behaviors. The emergence of new peaks in the UV–Vis spectra and the quenching of photoluminescence (PL) emission peaks suggest that their photochromism could be attributed to the photogeneration of radical species in the systems.