A multiple hydrogen-bond scaffold based on dipyrimidin-2-ylamine

Area of Science:

• Supramolecular Chemistry
• Organic Chemistry
• Crystallography

Background:

• Hydrogen-bond arrays are fundamental to molecular recognition.
• Dipyrimidin-2-ylamine derivatives offer versatile platforms for designing hydrogen-bonding motifs.
• Understanding factors influencing self-assembly is crucial for designing functional supramolecular systems.

Purpose of the Study:

• To synthesize and characterize an easily accessible multiple hydrogen-bond array based on dipyrimidin-2-ylamine.
• To investigate the impact of intramolecular hydrogen bonds, tautomeric equilibria, and steric effects on the self-association behavior of these molecules.
• To explore the persistence and binding selectivity of the hydrogen-bond array in solution.

Main Methods:

• Synthesis of dipyrimidin-2-ylamine derivatives.
• X-ray diffraction analysis to determine solid-state structure.
• (1)H NMR titrations to study solution-phase association and binding selectivity.

Main Results:

• An accessible multiple hydrogen-bond array was successfully synthesized.
• X-ray diffraction confirmed an acceptor-donor-acceptor (ADA) hydrogen-bonding array in the solid state.
• The ADA array was found to persist in solution, with selective binding observed for molecules featuring sterically nondemanding donor-acceptor-donor (DAD) arrays.

Conclusions:

• Dipyrimidin-2-ylamine serves as a robust scaffold for constructing multiple hydrogen-bond arrays.
• Intramolecular hydrogen bonding, tautomerism, and steric factors significantly modulate self-association behavior.
• The study demonstrates the potential for designing selective molecular recognition systems based on these hydrogen-bond arrays.