Dynamic Magneto‐Optical Response and Reversible Humidity‐Sensitive Luminescence Tuned by Intermolecular Interactions in Manganese Halides

Abstract Dynamically luminescent systems have driven great progress in materials and chemistry communities due to their structural flexibility and tunable photo functions. Eco‐friendly manganese (Mn)‐based hybrid halides are promising luminescent switches with high emission efficiency, low‐cost solution processibility, and low toxicity. However, limited success is achieved in tuning the dynamic luminescence of hybrid manganese halides in response to multiple stimuli. Herein, an effective way to manipulate the luminescence of hybrid manganese halides (Mn‐2DMAP and Mn‐4DMAP) through tailoring intermolecular interactions is reported. Stronger intermolecular interactions in Mn‐2DMAP induce structural distortion in the Mn─Cl bond lengths, resulting in a weaker crystal field compared to Mn‐4DMAP. The reduction in crystal‐field strength leads to a blue‐shifted emission and enhances the sensitivity to the external magnetic field. Mn‐4DMAP with weaker intermolecular interactions uptakes water molecules to form the hydrated Mn‐4DMAP‐H ₂ O which exhibits stronger intermolecular interactions. Taking advantage of their exceptional crystallinity, a 1D color‐tunable optical waveguide as a photonic memory system under humidity and heating dual‐stimuli are developed. Therefore, this work not only represents the first attempt to tune the luminescence of hybrid manganese halides at the intermolecular level, but also utilizes their dynamical emission for the application of optical waveguide switches at the micro/nanoscale.