A new quadruple hydrogen-bonding module based on five-membered heterocyclic urea structure

Area of Science:

• Supramolecular Chemistry
• Organic Chemistry
• Molecular Recognition

Background:

• Development of novel molecular modules for supramolecular assembly.
• Understanding the role of heterocyclic rings in non-covalent interactions.
• Previous studies on urea-based receptors and their complexes.

Purpose of the Study:

• To synthesize and characterize a new ADDA module, N,N -Di-4-triazolylurea (DTU).
• To investigate the complexation behavior of DTU with 2,7-diamido-1,8-naphthyridine (DAN).
• To compare the binding affinity of the DTU-DAN complex with related systems.

Main Methods:

• Synthesis of N,N -Di-4-triazolylurea (DTU).
• Formation and characterization of the ADDA*DAAD heterocomplex between DTU and DAN.
• Spectroscopic analysis to determine the stability constant (K(s)) of the complex in chloroform.

Main Results:

• DTU successfully formed a stable ADDA*DAAD heterocomplex with DAN.
• The stability constant (K(s)) for the DTU-DAN complex was determined to be 2.6 x 10(5) M(-1) in CHCl(3).
• The DTU-DAN complex exhibited a 100-fold greater binding affinity compared to a similar complex involving N,N -di-2-pyridylurea and DAN.

Conclusions:

• The replacement of pyridine rings with 1,2,3-triazole rings in urea-based modules significantly enhances binding affinity in supramolecular complexes.
• DTU represents a promising new module for constructing highly stable supramolecular assemblies.
• The study provides valuable insights into structure-affinity relationships in molecular recognition.