1,1′-Bi-2,2′-naphthol-Based Macrocycles as Dual Metal Cation Chemosensors: Synthesis, Spectroscopic Characterization, and Molecular Dynamics Insights

Abstract

This study reports the synthesis and characterization of two target macrocycles (5 and 10) intended to serve as chemosensors for metal cations relevant to biological processes. According to our findings, macrocycle 5 exhibited a marked fluorescence response toward Ag+ and Co2+, exhibiting 75.2% fluorescence quenching with Ag+ and fluorescence enhancement with Co2+ (73.5%). Comprehensive NMR studies provided in-depth insight into the binding mechanisms between the macrocycles and the investigated cations. The analysis revealed that the interaction with Ag+ is strongly influenced by conformational rearrangements of the macrocyclic framework in three-dimensional space, suggesting a dynamic adaptation of the host structure to optimize the coordination. Overall, these results indicate that macrocycle 5 can act as an effective dual chemosensor for metal cations, capable of discriminating between different species through distinct fluorescence responses, and thus represents a promising platform for the development of advanced sensing systems in biologically relevant environments.