Coordination chemistry in the solid: evidence for coordination modes within hybrid materials different from those in...

Area of Science:

• Materials Science
• Inorganic Chemistry
• Coordination Chemistry

Background:

• Cyclam-containing hybrid materials offer unique properties for metal ion complexation.
• Understanding europium(III) coordination in solid-state materials is crucial for developing new functional materials.
• The sol-gel process allows for the synthesis of tailored hybrid materials.

Purpose of the Study:

• To investigate two distinct routes for incorporating europium(III) salts into cyclam-based hybrid materials.
• To elucidate the coordination mode of europium(III) within these hybrid materials.
• To compare europium(III) coordination in solid-state hybrid materials versus solution.

Main Methods:

• Synthesis of N-tetrasubstituted cyclam derivatives bearing hydrolysable silyl groups.
• Two-step process: 1) Pre-complexation of europium(III) with silylated cyclam, followed by sol-gel processing. 2) Sol-gel processing of silylated cyclam, followed by europium(III) incorporation.
• Characterization of the resulting hybrid materials and europium coordination.

Main Results:

• Europium(III) incorporation into cyclam-hybrid materials is feasible via both explored routes.
• The coordination mode of europium(III) in the solid hybrid material differs significantly from that in solution.
• A novel 4N + 4N lanthanide coordination was achieved with europium(III) and cyclam moieties bearing N-alkyl substituents.

Conclusions:

• Hybrid materials provide a versatile platform for achieving lanthanide coordination not possible in solution.
• The N-alkyl substituents on cyclam moieties facilitate a unique 4N + 4N europium(III) coordination.
• This work establishes a new precedent for lanthanide coordination in solid-state hybrid materials.