Multiple hydrogen-bond-mediated molecular duplexes based on the self-complementary amidourea motif

Area of Science:

• Supramolecular Chemistry
• Organic Chemistry
• Chemical Physics

Background:

• The amidourea motif is a key functional group in supramolecular chemistry.
• Hydrogen bonding plays a crucial role in molecular self-assembly and recognition.
• Understanding the stability of self-complementary motifs is essential for designing complex molecular architectures.

Purpose of the Study:

• To investigate the self-complementary amidourea motif in solution and solid states.
• To explore the persistence of its hydrogen-bonding mode in longer molecular duplexes.
• To quantitatively determine the dimerization constants and solvent-dependent stability of amidourea homoduplexes.

Main Methods:

• Solid-state characterization of the amidourea motif.
• Solution-state investigations using Nuclear Magnetic Resonance (NMR) spectroscopy.
• Quantitative (1)H NMR dilution studies to determine dimerization constants in various solvent mixtures (DMSO-d(6)/CDCl(3)).

Main Results:

• The self-complementary amidourea motif is stabilized by four intermolecular tricenter hydrogen bonds.
• The observed hydrogen-bonding mode remains consistent in longer molecular duplexes based on the amidourea structure.
• Quantitative dimerization constants reveal that the homoduplex (2b.2b) exhibits high stability, particularly in low polarity solvents.

Conclusions:

• The amidourea motif provides a robust platform for self-complementary hydrogen bonding.
• The stability of amidourea-based homoduplexes is influenced by solvent polarity.
• This motif holds potential for constructing stable supramolecular assemblies and functional materials.