Manipulation of molecular aggregation and supramolecular structure using self-assembled lithium mixed-anion complexes

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Coordination Chemistry

Background:

• Designing materials with controlled dimensionality is crucial for advanced applications.
• Lithium alkoxide aggregates offer versatile building blocks for extended structures.
• Ditopic linkers like 1,4-dioxane enable the formation of complex networks.

Purpose of the Study:

• To synthesize zero-, one-, two-, and three-dimensional materials.
• To systematically control material dimensionality by varying component stoichiometry.
• To investigate the structural consequences of incorporating chelating units into lithium alkoxide aggregates.

Main Methods:

• Synthesis of homoleptic and mixed-anion lithium alkoxide complexes.
• Systematic variation of stoichiometry between 2,4,6-trimethylphenyllithium (ArOLi) and 2-(dimethylamino)ethoxolithium (ROLi).
• Utilizing 1,4-dioxane (diox) as a ditopic linker.
• Solid-state structural characterization of the resulting materials.

Main Results:

• A 3D diamondoid network ([{(ArOLi)4 x (diox)2}3(diox)]∞) was formed using only ArOLi.
• Sequential replacement of ArOLi with ROLi units successfully yielded 2D hexagonal net ([{(ROLi)(ArOLi)3 x (diox)(1.5)}1/2(C6H14)]∞), 1D chain ([(ROLi)4(ArOLi)2 x (diox)]∞), and 0D molecular dumbbell structures.
• Incorporation of ROLi units altered aggregation from tetrametallic Li4O4 to hexametallic Li6O6 units.

Conclusions:

• The dimensionality of lithium alkoxide-based materials can be precisely tuned by controlling component stoichiometry and linker interactions.
• Chelating ROLi units play a key role in dictating network dimensionality and aggregation states.
• This study demonstrates a rational approach to designing diverse dimensional supramolecular architectures.