Radical‐Induced Photochromic Silver(I) Metal–Organic Frameworks: Alternative Topology, Dynamic Photoluminescence and Efficient Photothermal Conversion Modulated by Anionic Guests

Abstract

Photogenerated radicals are an indispensable member of the state‐of‐the‐art photochromic material family, as they can effectively modulate the photoluminescence and photothermal conversion performance of radical‐induced photochromic complexes. Herein, two novel radical‐induced photochromic metal‒organic frameworks (MOFs), [Ag(TEPE)](AC)⋅7/4H2O⋅5/4EtOH (1) and [Ag(TEPE)](NC)⋅3H2O⋅EtOH (2), are reported. Distinctly different topological networks can be obtained by judiciously introducing alternative π–conjugated anionic guests, including a new topological structure (named as sfm) first reported in this work, describing as 4,4,4,4‐c net. EPR data and UV‐Vis spectra prove the radical‐induced photochromic mechanism. Dynamic photochromism exhibits tunability in a wide CIE color space, with a linear segment from yellow to red for 1, while a curved coordinate line for 2, resulting in colorful emission from blue to orange. Moreover, photogenerated TEPE* radicals effectively activate the near‐infrared (NIR) photothermal conversion effect of MOFs. Under 1 W cm‐2 808 nm laser irradiation, the surface temperatures of photoproducts 1* and 2* can reach ~160 ℃ and ~120 ℃, respectively, with competitive NIR photothermal conversion efficiencies η = 51.8% (1*) and 36.2% (2*). This work develops a feasible electrostatic compensation strategy to accurately introduce photoactive anionic guests into MOFs to construct multifunctional radical‐induced photothermal conversion materials with tunable photoluminescence behavior.