Coupling d⁶ Ir(III) and d⁸ Pt(II) Chromophores.

Area of Science:

• Inorganic Chemistry
• Materials Science
• Photochemistry

Background:

• Octahedral d6 (e.g., Ir3+) and square planar d8 (e.g., Pt2+) polypyridyl complexes are well-studied luminescent materials.
• These complexes possess distinct photophysical and photoreactivity characteristics.

Purpose of the Study:

• To synthesize and characterize novel d6-d8 iridium-platinum (Ir-Pt) hybrid complexes.
• To investigate the photophysical properties, including absorption, emission, and excited-state behavior, of these new hybrid complexes.

Main Methods:

• Synthesis of Ir-Pt hybrid complexes via coordination of iridium metalloligands to platinum(terpyridine) units.
• X-ray crystallography for structural determination of the cofacial orientation of chromophores.
• Density Functional Theory (DFT) and time-dependent DFT (TD-DFT) calculations for electronic structure and transition analysis.

Main Results:

• X-ray structures reveal cofacial orientation of IrL2 and Pt(terpy) chromophores with specific interplanar distances.
• DFT calculations indicate localization of HOMO and LUMO within the IrL2 and Pt(terpy) units, respectively.
• Complexes exhibit low-energy absorption bands (460-534 nm) attributed to interchromophore-charge-transfer (ICCT) transitions.
• Emissive 3ICCT excited states result in long-lived phosphorescence in the near-infrared region (668-710 nm).

Conclusions:

• The synthesized Ir-Pt hybrid complexes demonstrate tunable photophysical properties driven by ICCT transitions.
• These complexes offer potential applications in areas requiring long-lived phosphorescence, particularly in the near-infrared spectrum.