Selective detection of DABCO using a supramolecular interconversion as fluorescence reporter

Area of Science:

• Supramolecular Chemistry
• Coordination Chemistry
• Materials Science

Background:

• Multicomponent self-assembly offers pathways to complex molecular architectures.
• Controlling the dynamic interconversion between different supramolecular structures is a key challenge.
• Guest-induced responses in supramolecular systems are crucial for molecular devices.

Purpose of the Study:

• To investigate the quantitative double self-sorting between two distinct copper-based supramolecular complexes.
• To explore the role of 1,4-diazabicyclo[2.2.2]octane (DABCO) as a trigger for structural interconversion.
• To develop a fluorescence-based method for monitoring structural changes and detecting DABCO.

Main Methods:

• Synthesis and characterization of multicomponent supramolecular rectangles and sandwich complexes.
• X-ray crystallography to determine the solid-state structures.
• Spectroscopic methods (fluorescence) to monitor the self-sorting process and guest binding.
• Analysis of structural changes and spatial distances between components.

Main Results:

• Two distinct supramolecular architectures, a rectangle [Cu4(1)2(2)2]4+ and a sandwich complex [Cu2(1)(2)(4)]2+, were formed.
• The inclusion and release of DABCO (4) quantitatively triggered the reversible switching between these architectures.
• Fluorescence changes at zinc porphyrin sites correlated with the structural interconversion.
• Significant spatial contraction/expansion of zinc porphyrin-zinc porphyrin distances (31.2/38.8 Å to 6.6 Å) was observed.
• The supramolecular interconversion enabled highly selective detection of DABCO.

Conclusions:

• A quantitative and reversible self-sorting system between two multicomponent supramolecular architectures was successfully developed.
• DABCO acts as a key trigger, enabling clean and fully reversible switching between the architectures.
• The observed fluorescence changes and dramatic spatial rearrangements provide a sensitive platform for molecular sensing.
• This work demonstrates the potential of dynamic supramolecular systems for selective guest detection.