Supramolecular Self-Assembly Driven Selective Sensing of Phosphates

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Chemical Sensing

Background:

• Development of selective anion sensors is crucial for various chemical and biological applications.
• Ruthenium(II) complexes offer tunable photophysical properties for sensing applications.
• Understanding anion-selectivity mechanisms requires integrated spectroscopic and structural analysis.

Purpose of the Study:

• To synthesize and characterize a new bis-heteroleptic ruthenium(II) complex for anion sensing.
• To investigate the complex's selectivity towards specific anions, particularly phosphates.
• To elucidate the origin of selectivity and the formation of supramolecular architectures.

Main Methods:

• Synthesis and characterization of the ruthenium(II) complex (1[PF6]).
• Spectroscopic studies (UV-Vis absorption, emission spectroscopy, 1H-DOSY NMR, solid-state PL).
• Macroscopic investigations (SEM, DLS) and single crystal X-ray crystallography.

Main Results:

• The complex 1[PF6] demonstrated selective sensing of phosphates over other anions in solution and solid states.
• Phosphate binding induced significant changes in absorption spectra and amplified 3MLCT emission.
• Macroscopic studies revealed supramolecular assembly formation via halogen bonding and pi-pi stacking in the presence of dihydrogen phosphate.

Conclusions:

• The designed ruthenium(II) complex serves as an effective sensor for phosphates.
• Halogen bonding and pi-pi stacking interactions are key to the observed supramolecular architecture and sensing mechanism.
• The study provides insights into the design principles for selective anion sensors with macroscopic outputs.