Composition- and size-controlled cyclic self-assembly by solvent- and C60-responsive self-sorting.

Area of Science:

• Supramolecular Chemistry
• Organic Chemistry
• Materials Science

Background:

• Hydrogen-bonded self-assembly is a key strategy for creating complex molecular architectures.
• Chiral receptors are crucial for enantioselective recognition and separation.
• Fullerenes (C60, C70) present unique host-guest chemistry challenges due to their electronic properties.

Purpose of the Study:

• To synthesize novel hydrogen-bonded chiral cavity receptors.
• To investigate the solvent- and guest-controlled self-assembly and self-sorting behavior of these receptors.
• To explore their host-guest interactions with fullerenes.

Main Methods:

• Synthesis of monomers featuring the ureidopyrimidinone motif and bicyclo[3.3.1]nonane framework.
• Solvent-dependent studies (chloroform, toluene) to analyze self-assembly equilibria.
• Spectroscopic and crystallographic analyses to characterize aggregates and host-guest complexes.
• Investigation of fullerene binding affinities and selectivity.

Main Results:

• Selective formation of kinetically inert cyclic tetramers in chloroform.
• Equilibrium between tetrameric and pentameric aggregates observed in toluene.
• High affinity of tetrameric aggregates towards C60 and C70 fullerenes in aromatic solvents.
• Switchable host-guest interactions for fullerenes modulated by solvent polarity.

Conclusions:

• The designed chiral receptors exhibit tunable self-assembly based on solvent conditions.
• Fullerene binding can be controlled by solvent and influences aggregate composition.
• These systems function as novel self-sorting devices for molecular recognition and separation.