Luminescent gold-thallium derivatives with a pyridine-containing 12-membered aza-thioether macrocycle

Area of Science:

• Coordination Chemistry
• Organometallic Chemistry
• Materials Science

Background:

• The coordination chemistry of macrocyclic ligands with metal ions is crucial for developing novel materials.
• Understanding metal-ligand interactions provides insights into complex structural motifs and properties.

Purpose of the Study:

• To investigate the coordination modes of 2,5,8-trithia[9](2,6)pyridinophane (L) with thallium(I), gold(III), and gold(I) ions.
• To characterize the structural, electronic, and photophysical properties of the resulting metal complexes.
• To explore the potential of these complexes in materials science, particularly their thermochromic behavior.

Main Methods:

• Single-crystal X-ray diffraction for structural determination of metal complexes.
• Spectroscopic techniques (UV-Vis, luminescence) for photophysical characterization.
• Density Functional Theory (DFT) calculations to investigate electronic structure and emission origins.

Main Results:

• Complexes of thallium(I), gold(III), and gold(I) with the macrocyclic ligand (L) were synthesized and characterized.
• A heterometallic Tl(I)/Au(I) complex, {[Au(C6F5)2Tl]2(L)}n, formed a polymeric structure with a unique Au2Tl2 core and unsupported Au-Tl bonds.
• This heterometallic complex exhibited thermochromic behavior with temperature-dependent luminescence, attributed to different thallium environments and MM'CT transitions.

Conclusions:

• The ligand L displays versatile coordination modes with different metal ions, leading to diverse structural outcomes.
• The heterometallic polymer exhibits intriguing structural complexity and photophysical properties, including thermochromism.
• DFT calculations provide insights into the origin of luminescence, highlighting the potential of these complexes for further investigation in materials science.