Luminescent Coordination Glass: Remarkable Morphological Strategy for Assembled Eu(III) Complexes

Area of Science:

• Materials Science
• Inorganic Chemistry
• Coordination Chemistry

Background:

• Europium(III) ions are known for their luminescent properties.
• Coordination polymers and glasses offer tunable material characteristics.
• Designing ligands with specific geometries influences coordination structures.

Purpose of the Study:

• To synthesize novel luminescent Europium(III) coordination glasses.
• To investigate the effect of bent-angled phosphine oxide ligands on glass formation and structure.
• To characterize the luminescence and thermal properties of the synthesized materials.

Main Methods:

• Synthesis of Eu(III) coordination glasses using hexafluoroacetylacetonato (hfa) and bent-angled phosphine oxide (o-, m-, p-dpeb) ligands.
• Single-crystal X-ray diffraction analysis to determine coordination structures.
• Density Functional Theory (DFT) calculations to understand structural properties.
• Differential scanning calorimetry (DSC) for glass-transition temperature (Tg) determination.
• Luminescence spectroscopy to measure quantum yields (ΦLn).

Main Results:

• Three novel luminescent Eu(III) coordination glasses, [Eu(hfa)3(o-dpeb)]2, [Eu(hfa)3(m-dpeb)]3, and [Eu(hfa)3(p-dpeb)]n, were successfully synthesized.
• Coordination structures varied from dinuclear to trinuclear and polymeric, influenced by the regiochemistry of the dpeb ligands.
• The synthesized glasses displayed characteristic glass-transition temperatures (Tg) ranging from 25 to 96 °C.
• Strong luminescence properties were observed with high luminescence quantum yields (ΦLn) between 72% and 94%.

Conclusions:

• The regiochemistry of bent-angled phosphine oxide ligands critically affects the coordination structure and glass-forming ability of Eu(III) complexes.
• These novel coordination glasses possess excellent thermal stability and efficient luminescence, making them promising for optical applications.
• The study demonstrates a rational design approach for developing new luminescent inorganic materials.