Ferrocene-based conjugated macrocycles: shotgun synthesis, size-dependent properties and tunable fluorescence intensity

Abstract

The synthesis, structure, and size-dependent properties of ferrocene-embedded conjugated macrocycles are described. The one-pot, two-component “shotgun” synthesis greatly expands the structural diversity and functionality of nanohoops. These η⁵-type coordination metal-nanohoops exhibit intriguing properties, including reversible redox behavior and collisional quenching with fullerenes. Notably, the addition of oxidants enhances their fluorescence intensity, while fullerenes quench it. Detailed theoretical and experimental studies reveal that fine-tuning the nanohoop size significantly influences not only the molecular conformation but also its electronic structure and photophysical properties.