Group 13 and lanthanide complexes with mixed O,S anionic ligands derived from maltol

Area of Science:

• Coordination Chemistry
• Inorganic Chemistry
• Materials Science

Background:

• Maltol derivatives are versatile ligands in coordination chemistry.
• Exploring O,S mixed-donor ligands for trivalent metal ions is an active research area.
• Lanthanide complexes have applications in luminescence and catalysis.

Purpose of the Study:

• To synthesize and characterize novel metal complexes using O,S binding ligand precursors derived from maltol.
• To investigate the coordination behavior of pyranthiones and pyridinethiones with gallium(III), indium(III), and lanthanide(III) ions.
• To determine the structural and spectroscopic properties of the resulting metal complexes.

Main Methods:

• Synthesis of four O,S mixed-donor ligand precursors: thiomaltol (Htma), ethylthiomaltol (Hetma), 3-hydroxy-2-methyl-4(H)-pyridinethione (Hmppt), and 3-hydroxy-1,2-dimethyl-4-pyridinethione (Hdppt).
• Chelation of ligand precursors with gallium(III), indium(III), and lanthanide(III) ions.
• Characterization using elemental analysis, mass spectrometry, IR, and NMR spectroscopy.
• X-ray crystallography for structural determination of selected compounds.

Main Results:

• Successful synthesis of monomeric and dimeric ligand precursors, with characterization including acidity constants and crystal structures.
• Formation of novel tris(bidentate ligand) complexes with Ga(III) and In(III), including the fac isomer of Ga(tma)(3).
• Synthesis of lanthanide complexes of the type LnL(3).xH(2)O and LnL(2)(OH).xH(2)O using Htma and Hetma.

Conclusions:

• The O,S mixed-donor ligands derived from maltol are effective chelators for Ga(III), In(III), and Ln(III) ions.
• The synthesized complexes exhibit diverse coordination modes and structural characteristics.
• This study expands the library of metal complexes with potential applications in catalysis, imaging, or materials science.