Solid-State Emissive Metallo-Supramolecular Assemblies of Quinoline-Based Acyl Hydrazone

Area of Science:

• Materials Science
• Analytical Chemistry
• Supramolecular Chemistry

Background:

• Fluorescence-based sensors are crucial for metal ion detection due to their simplicity and usability.
• Developing novel sensory materials with enhanced properties is a key research area.

Purpose of the Study:

• To synthesize and characterize a novel bis-quinoline-based acyl hydrazone (bQH) for selective metal ion sensing.
• To investigate the fluorescence properties and binding behavior of bQH with metal ions, particularly zinc (Zn2+).

Main Methods:

• Facile synthesis of bQH via condensation of hydrazide and aldehyde.
• Characterization using UV-Vis, photoluminescence (PL), nuclear magnetic resonance (NMR), ICP-OES, and EDS mapping.
• Investigation of bQH:Zn2+ binding modes (1:1 and 1:2) and metallo-supramolecular assembly.

Main Results:

• bQH demonstrated selective Zn2+ binding and emissive properties, especially in the solid-state.
• Two binding modes (1:1 and 1:2 bQH:Zn2+) were identified, controlled by Zn2+ ion concentration.
• The 1:1 complex formed polymeric arrays via metallo-supramolecular assembly, maintaining solid-state fluorescence with high intensity.

Conclusions:

• The novel bQH acts as an effective fluorescent sensor for Zn2+ ions.
• The metallo-supramolecular assembly of bQH-Zn2+ complexes enhances solid-state fluorescence.
• bQH shows potential for developing advanced, highly fluorescent metal ion detection materials.