Pore size or hydrophobicity, what enables solid state switching of donor acceptor

Project Description

Donor-acceptor Stenhouse adducts (DASAs), a class of light-responsive materials, has gained significant interest as smart responsive materials due to their sensitivity to external environment. However, most DASA-based photoswitching occurs in solution, and their practical utility in solid-state remains challenging because of intermolecular stacking leading to restriction in intermolecular rotation and cyclization. Moreover, DASAs can decompose in the presence of polar protic solvents, further limiting their use. Isolating these photoswitches in the pockets of metal-organic frameworks (MOFs) is one way to successfully achieve reversible photoisomerization in solid state. The proposed study aims to unravel two key factors affecting DASAs' switching within the MOF environment: MOF pore size and inherent pore hydrophobicity. To achieve this, two isomeric MOFs, UiO-66 and MIL-140A, will be used to fabricate DASA@MOF composites with four DASAs, and their photo/thermal switching capabilities will be investigated through a combination of theoretical and experimental techniques. A representative example is shown below.

Instruments