Phosphorescent binuclear iridium complexes based on terpyridine-carboxylate: an experimental and theoretical study

Area of Science:

• Coordination Chemistry
• Photophysics
• Materials Science

Background:

• Iridium(III) complexes are widely studied for their phosphorescent properties.
• Developing dinuclear iridium complexes can lead to enhanced optical characteristics compared to mononuclear systems.
• Tuning ligand structures is crucial for controlling photophysical behavior.

Purpose of the Study:

• Synthesize and characterize novel phosphorescent binuclear iridium(III) complexes.
• Investigate the structural, electronic, and photophysical properties of these dinuclear complexes.
• Evaluate their potential for applications in optical materials.

Main Methods:

• Synthesis of iridium(III) complexes (Ir1 and Ir2).
• Characterization using X-ray diffraction, NMR, UV-vis absorption, and emission spectroscopy.
• Density Functional Theory (DFT) and time-dependent DFT (TD-DFT) calculations.

Main Results:

• Successful synthesis and characterization of two binuclear iridium(III) complexes.
• Complexes exhibit intense luminescence in solution with specific emission maxima.
• Ir1 demonstrates a high emission quantum yield (~18%), comparable to mononuclear analogues, with a doubled molar extinction coefficient.
• Structural analysis confirms equivalent iridium centers in solution and solid state for Ir2.

Conclusions:

• The synthesized binuclear iridium(III) complexes possess significant luminescence properties.
• These complexes are promising building blocks for polymetallic assemblies with improved optical performance.
• Computational studies provide valuable insights into their photophysical mechanisms.