A solvent crafted alternate [Zn3/Zn4] cluster driven MOF and its analogous MOG: structural elucidation integrated with advanced bilirubin detection and encryption strategies

Abstract

The synergy between coordination chemistry and materials design facilitates the development of sophisticated luminescent systems with advanced applications. This study details the preparation and analysis of a rare alternate [Zn₃/Zn₄] cluster-based metal–organic framework (MOF), SSICG15, and its analogous metal–organic gel (MOG), SSICG15-MOG, both originating from the same naphthalimide ligand (H₂L) and zinc precursor. The existence of trinuclear and tetranuclear zinc clusters, distinctive to the structure, offers substantial insights into the coordinating environment of the MOF structure. The xerogel, obtained from the MOG, exhibited notable crystallinity as evidenced by PXRD studies. The probable structure of the MOG was determined by simulating the PXRD data of the related xerogel using molecular dynamics simulations, informed by ESI-MS data and the coordination network of the MOF. Both materials exhibited exceptional luminescence, facilitating their application in sophisticated anticounterfeiting methods, including QR code encoding along with anticounterfeiting ink preparation. These materials show great sensitivity and selectivity for the detection of bilirubin (BR), which is a crucial biomarker for jaundice diagnosis and monitoring, with a LOD of 20 nM for SSICG15-MOG and 26.5 nM for SSICG15. Both materials combine photonic capabilities with excellent diagnostic accuracy, which makes them extremely attractive for analytical and biological applications.