A Highly Selective Chemosensor for Cyanide Derived from a Formyl-Functionalized Phosphorescent Iridium(III) Complex.

Area of Science:

• Inorganic Chemistry
• Materials Science
• Analytical Chemistry

Background:

• Development of sensitive and selective methods for cyanide detection is crucial due to its toxicity.
• Phosphorescent iridium(III) complexes offer potential for sensing applications due to their unique photophysical properties.

Purpose of the Study:

• To synthesize and characterize a new phosphorescent iridium(III) complex for cyanide detection.
• To investigate the sensing mechanism and performance of the iridium(III) complex towards cyanide ions.

Main Methods:

• Synthesis and full characterization of the iridium(III) complex using spectroscopic techniques and X-ray diffraction.
• Investigation of cyanide binding properties via UV-vis absorption and photoluminescence spectroscopy.
• Fabrication of phosphorescent test strips for practical cyanide detection.
• Computational analysis using DFT and TD-DFT to understand electronic structure and transitions.

Main Results:

• The synthesized iridium(III) complex exhibits intense red phosphorescence in solid state and faint emission in solution.
• Upon addition of cyanide, a visible color change from orange to yellow and a dramatic photoluminescence enhancement (~5.36 × 10(2)-fold) with a blue shift (~155 nm) were observed.
• A low detection limit of 2.16 × 10(-8) M was achieved in solution, and test strips showed a nanogram-level detection limit (~265 ng/mL).

Conclusions:

• The developed phosphorescent iridium(III) complex is a highly effective probe for sensitive and selective cyanide detection.
• The cyanohydrin formation mechanism is confirmed as the basis for cyanide sensing.
• The practical application of the complex in test strips demonstrates its utility for trace cyanide analysis.