The preparation of single-chain magnets (SCMs) with photo-switchable bistable states is essential for the development of high-density photo-recording devices. However, the reversible switching of the SCM behavior upon light irradiation is a formidable challenge. Here we report a well-isolated double zigzag chain {[Fe(bpy)(CN)₄]₂[Co(phpy)₂]}·2H₂O (bpy = 2,2′-bipyridine, phpy = 4-phenylpyridine), which exhibits reversible redox reactions with interconversion between Fe^III_LS(μ-CN)Co^II_HS(μ-NC)Fe^III_LS (LS = low-spin, HS = high-spin) and Fe^III_LS(μ-CN)Co^III_LS(μ-NC)Fe^II_LS linkages under alternating irradiation with 808 and 532 nm lasers. The bidirectional photo-induced metal-to-metal charge transfer results in significant changes of anisotropy and intrachain magnetic interactions, reversibly switching the SCM behavior. The on-switching SCM behavior driven by light irradiation at 808 nm could be reversibly switched off by irradiation at 532 nm. The results provide an additional and independent way to control the bistable states of SCMs by switching in the 0 → 1 → 0 sequence, with potential applications in high density storage and molecular switches.

中文翻译：

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通过光诱导双向金属到金属的电荷转移来切换单链磁体行为

具有光可切换双稳态的单链磁体（SCM）的制备对于开发高密度光记录设备至关重要。但是，光辐照下SCM行为的可逆转换是一个巨大的挑战。在这里，我们报告一个完全隔离的双曲折链{[Fe（bpy）（CN）₄ ] ₂ [Co（phpy）₂ ]}·2H ₂ O（bpy = 2,2'-联吡啶，phpy = 4-苯基吡啶） Fe ^III _LS（μ-CN），Co ^II _HS（μ-NC），Fe ^III _LS（LS =低自旋，HS =高自旋）和Fe ^III _LS（μ-CN）之间互变而表现出可逆的氧化还原反应Co ^III _LS（μ-NC）Fe ^II _LS键在808和532 nm激光交替照射下。双向光诱导的金属间电荷转移导致各向异性和链内磁相互作用的显着变化，从而可逆地切换SCM行为。可以通过532 nm的照射可逆地关闭由808 nm的光照射驱动的开通SCM行为。结果提供了另外一种独立的方式，通过以0→1→0的顺序切换来控制SCM的双稳态，在高密度存储和分子开关中有潜在的应用。