Rational Design of Rigid Chiral Ir(III)-Eu(III) Dyads: Intense Circularly Polarized Luminescence via Visible-Light...

Area of Science:

• Coordination Chemistry
• Materials Science
• Biophysical Chemistry

Background:

• Lanthanide-based circularly polarized luminescence (CPL) probes face challenges in biological applications due to kinetic lability and excitation toxicity.
• Existing probes often exhibit limited stability in biological environments, hindering their utility.

Purpose of the Study:

• To engineer robust and bright chiral lanthanide-based CPL probes for biological imaging.
• To overcome kinetic lability and excitation-related toxicity issues associated with current CPL probes.

Main Methods:

• Developed rigid chiral Ir(III)-Eu(III) dyads using a stereoselective "complex-as-ligand" strategy.
• Incorporated a kinetically inert DO3A macrocycle to enhance structural rigidity and stability.
• Utilized visible-light sensitization with an integrated Ir(III) antenna for excitation.

Main Results:

• Achieved intense CPL (|g_lum| = 0.12) and high brightness (B_CPL ≈ 8 M⁻¹ cm⁻¹).
• Demonstrated low-phototoxicity confocal imaging in HeLa cells using visible-light excitation (λ_ex = 425 nm).
• Confirmed exceptional stability against biological interferents and preservation of chiroptical signals with ct-DNA.

Conclusions:

• The engineered rigid Ir(III)-Eu(III) dyads provide a stable and bright platform for CPL bioimaging.
• This work presents a general strategy for creating robust, visible-light-excitable rare-earth chiroptical materials.
• Opens new avenues for enantioselective sensing and specific chiroptical bioimaging applications.