Post‐Synthetic Modification of ZIF‐8 Crystals and Films through UV Light Photoirradiation: Impact on the Physicochemical Behavior of the MOF

• Published in: Chemphyschem 2019-12, Vol.20 (23), p.3201-3209
• Main Authors: Papurello, Rocío L., Lozano, Luis A., Ramos‐Fernández, Enrique V., Fernández, José L., Zamaro, Juan M.
• Format: Article
• Language: English
• Subjects: Crystal structure; Electromagnetic absorption; Metal-organic frameworks; Nitric oxide; Organic chemistry; post-synthetic modifications; surface properties; Surface stability; Thermal stability; ultraviolet light; zeolitic imidazolate frameworks; ZIF-8
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.201900863

The physicochemical modification of Metal‐Organic Frameworks (MOFs) is a current challenge in the search to improve their performance in different technological applications. In this work we analyze the post‐synthetic modification of ZIF‐8 crystals and films through a simple and clean treatment that involves the exposure to a UV lamp under environmental conditions. It is demonstrated that a short treatment alters the MOF structure and chemistry, providing a modified ZIF‐8 due to partial disconnections of its structure which increase the amount of terminal surface species such as Zn−OH and −C=N‐H, but without compromising the overall MOF structure, specific surface area or thermal stability. Additionally, it leads to changes in several properties of the ZIF‐8, such as its capacity to accumulate charge through pseudocapacitive processes, its interaction with nitric oxide and its light absorption behavior. This strategy of modifying ZIF‐8 without the use of chemicals through a gentle disconnection of its own structure could open new perspectives of post‐functionalization of crystals and films of ZIF‐8 to be used in a wide range of applications. A green post‐synthetic modification of ZIF‐8 crystals and films is reported. The method consists of a simple UV photoirradiation treatment – without the use of chemicals – that allows an alteration of the ZIF‐8 surface chemistry. This is reflected in changes in voltammetric responses, nitric oxide uptake, and light interaction.