One Dianionic Luminophore with Three Coordination Modes Binding Four Different Metals: Toward Unexpectedly...

Area of Science:

• Coordination Chemistry
• Photophysics
• Materials Science

Background:

• Luminescent coordination compounds are crucial for advanced optical and electronic devices.
• Tuning photophysical properties requires precise control over ligand design and metal coordination.
• Understanding structure-property relationships is key to developing efficient luminescent materials.

Purpose of the Study:

• To synthesize and characterize novel coordination compounds with a versatile dianionic luminophore.
• To investigate the impact of metal centers (Pd(II), Pt(II), Au(III), Hg(II)) and coordination modes on photophysical properties.
• To explore temperature and phase-dependent luminescence for potential applications.

Main Methods:

• Synthesis and structural characterization of ligand precursor (H2L) and six transition metal complexes.
• Photophysical measurements including photoluminescence quantum yields (ΦL) and excited state lifetimes (τ) at various temperatures and phases.
• Analysis of non-radiative decay pathways and their suppression in different environments.

Main Results:

• Six new coordination compounds were successfully synthesized and characterized.
• Five complexes exhibit notable room-temperature luminescence in solution.
• Embedding complexes in glassy matrices at 77 K significantly enhances luminescence.
• [HLPdCNtBu] shows over 30-fold increase in ΦL and τ at low temperatures.
• The Hg(II) complex achieves >60% ΦL and millisecond lifetimes, a first for its class.

Conclusions:

• Judicious ligand design enables the creation of coordination compounds with tunable excited-state properties.
• The coordination mode and metal center significantly influence luminescence efficiency and lifetime.
• These findings offer a pathway towards developing advanced luminescent materials for various applications.