Electron transfer photochromism of Ln-based (Ln = Dy, Tb) coordinated polymers for reversibly switching off/on single-molecule magnetic behavior

Switching on/off single-molecule magnets (SMMs) at room temperature is still a challenge in moleculebased magnets. Herein, two photochromic Ln-based (Ln = Dy, Tb) phosphonate coordinated polymers were synthesized with regulable SMM behavior. The reversible room-temperature photo-coloration was an electron transfer process generation of relatively stable radicals, characterized by structural analyses, ultraviolet-visible, luminescence and spin resonance spectra magnetic measurements. Importantly, owing to the antiferromagnetic coupling interactions between Ln3+ ions photogenerated light irradiation surprisingly switched off behavior, showing first example radicalquenched SMMs molecule-based Moreover, silient behavior could be recovered after eliminating radicals via heat treatment, off/on switch heat. This work constructs system for switching through photochromism, providing visual operation way naked-eye-detectable coloration switchable SMMs.