Novel Photoactive Spirooxazine Based Switch@MOF Composite Materials

Abstract

Molecules, which reversibly transform between two structural configurations upon excitation with electromagnetic radiation, are attractive candidates for the design of smart materials e. g. memory devices. A possible approach for the development of such smart materials is the construction of hybrid systems that contain these photochromic molecules as well as a porous host matrix, which enables their switching process in the solid state. We herein present the first light-responsive materials consisting of the photoswitchable spirooxazine 1,3,3-trimethyl indolinonaphthospirooxazine (SP−O) and crystalline porous MOF (metal–organic framework) hosts, namely MOF-5, MIL-68(In), MIL-68(Ga), and MIL-53(Al), which were combined to form hybrid SP−O@MOF composites. These systems show a reversible photochromic response and host-dependent absorption maxima of the incorporated guest molecules. Most remarkably, SP−O is extremely photostable upon repetitive and prolonged UV light exposure especially inside MOF-5, making these composite materials attractive candidates for potential applications in data storage devices.