Multiple pathways for lanthanide sensitization in self-assembled aqueous complexes.

Area of Science:

• Photochemistry and Photophysics
• Materials Science
• Computational Chemistry

Background:

• Lanthanide photoluminescence (PL) is valuable for technology and bioimaging due to narrow emission bands and long lifetimes.
• Water molecules typically quench lanthanide emitters, limiting their use in aqueous environments.
• A previously developed luminophore, 8-methoxy-2-oxo-1,2,4,5-tetrahydrocyclopenta[de]quinoline-3-phosphonic acid (PAnt), shows dynamic coordination with Tb(III) and Eu(III).

Purpose of the Study:

• To conduct an in-depth photophysical and computational study of Eu(III) and Tb(III) complexes with PAnt in aqueous media.
• To elucidate the different sensitization mechanisms for Eu(III) and Tb(III) in stable complexes.
• To enable new applications in bioimaging and novel emitting materials by understanding aqueous behavior.

Main Methods:

• Time-dependent density functional theory (TD-DFT) calculations.
• Photophysical characterization of lanthanide complexes.
• Analysis of energy transfer mechanisms in aqueous solutions.

Main Results:

• Demonstrated distinct sensitization pathways for Eu(III) and Tb(III) within stable complexes formed in water.
• Confirmed the improved performance of PAnt-lanthanide complexes in PL lifetime imaging microscopy (PLIM) compared to conventional agents.
• Provided insights into the factors governing lanthanide luminescence in aqueous environments.

Conclusions:

• Understanding the unique aqueous sensitization mechanisms of Eu(III) and Tb(III) is crucial for developing advanced luminescent materials.
• The PAnt ligand facilitates stable lanthanide complex formation in water, overcoming common quenching issues.
• This research opens avenues for novel bioimaging probes and functional emitting materials utilizing lanthanide luminescence.