Nanoporous Metal-Organic Framework Thin Films with Embedded Fulgide for Light-Modulated Guest Adsorption and Diffusion

Smart and photoresponsive materials and thin films allow the dynamic remote control of their central properties. By incorporation of photochromic molecules in nanoporous metal-organic frameworks (MOFs), the interaction between the MOF host and the guest molecules in the pores can be modified. Here, a MOF film of type UiO-68 is presented in which the photoswitchable feature is added by embedment of photochromic fulgide molecules of type Aberchrome 670 in the pores. The photoisomerization in the pores is explored by UV- vis and infrared spectroscopy, and the transient uptake of toluene and methanol probe molecules is explored using a quartz crystal micro-balance. For the first time, a fulgide-based nanoporous material is used to remote-control the adsorption and diffusion properties. We find that the toluene uptake amount can be increased by 37% and the toluene diffusion coefficient can be increased by 40% when reversibly photoswitching the embedded fulgide from its E-form to C-form. In this way, this study aims to contribute to the field of light-responsive nanoporous materials and thus expands the range of smart coatings.

Automated summary

The study demonstrates the use of smart and photoresponsive materials to remotely control their key properties. By embedding photochromic molecules in nanoporous metal-organic frameworks, the interaction between the host and guest molecules can be modified. The research shows for the first time that the adsorption and diffusion properties can be remotely controlled using a fulgide-based nanoporous material.