A water-soluble and highly phosphorescent cyclometallated iridium complex with versatile sensing capability

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Analytical Chemistry

Background:

• Cyclometallated iridium complexes exhibit unique photophysical properties.
• Development of sensitive and selective chemosensors is crucial for biological and environmental monitoring.
• Bovine serum albumin (BSA) is a key biomarker in various physiological conditions.

Purpose of the Study:

• To synthesize and characterize a water-soluble, highly phosphorescent cyclometallated iridium complex.
• To investigate the complex's potential as a multifunctional chemosensor.
• To evaluate its utility for detecting tryptophan, BSA, and Cu2+, and for cell imaging.

Main Methods:

• Synthesis and characterization of the iridium complex [(pq)2Ir(bpy-COOK)]+Cl−.
• Investigation of phosphorescence quenching by tryptophan via photoinduced electron-transfer (PET).
• Analysis of phosphorescence enhancement upon BSA binding and subsequent quenching by Cu2+.

Main Results:

• The synthesized iridium complex is water-soluble and highly phosphorescent.
• Tryptophan selectively quenches the complex's phosphorescence through a PET mechanism.
• BSA binding enhances phosphorescence, which is then quenched by Cu2+, enabling sequential detection.

Conclusions:

• The iridium complex functions as a versatile, multifunctional chemosensor.
• It allows for sensitive and selective determination of tryptophan, BSA, and Cu2+.
• The complex shows promise for biological sample analysis and advanced cell imaging.