Energy transfer in supramolecular [Crypt-RE]-[W₆I₁₄] solids

Area of Science:

• Inorganic Chemistry
• Materials Science
• Photochemistry

Background:

• Tungsten iodide clusters ([W6I14]2-) exhibit phosphorescence.
• Molecular oxygen quenches this phosphorescence via energy transfer from excited triplet states.

Purpose of the Study:

• Investigate deactivation pathways of excited triplet states in [W6I14]2- clusters.
• Explore energy transfer from these clusters to rare earth ions within supramolecular assemblies.

Main Methods:

• Synthesis of supramolecular assemblies comprising [W6I14]2- clusters and metal cryptates.
• Investigation of crystal structures and photophysical properties.
• UV/Vis photoexcitation and emission spectroscopy.

Main Results:

• Solid-state [Crypt-A]-[W6I14] and [Crypt-RE]-[W6I14] assemblies showed phosphorescence from either the cluster or the rare earth metal (RE) center.
• Demonstrated cluster-to-cryptate energy transfer evidenced by Yb3+ (977 nm) and Nd3+ (1072 nm) emissions.
• Confirmed effective excitation of near-infrared-emitting rare earth ions up to 550 nm.

Conclusions:

• Supramolecular assemblies facilitate energy transfer from tungsten iodide clusters to rare earth ions.
• These materials offer a pathway for efficient excitation of near-infrared emitters.
• Potential applications in optoelectronics and sensing.