Investigating halogen bonds in substituted graphitic carbon nitride through vibrational spectroscopy

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Computational Chemistry

Background:

• Graphitic carbon nitride (g-C3N4) is a metal-free material with a tunable electronic structure.
• Halogen bonding (XB) is a non-covalent interaction with growing applications in materials science and drug design.
• Functionalization of g-C3N4 can modify its electronic properties and non-covalent interaction capabilities.

Purpose of the Study:

• To investigate the potential of substituted g-C3N4 as halogen bond acceptors.
• To systematically study halogen bonding interactions with various XB donors and acceptor stoichiometries.
• To analyze the interplay between halogen bonding and hydrogen bonding in these complexes.

Main Methods:

• Computational modeling of g-C3N4 triazine units substituted with OH, SH, and PH2 groups.
• Complexation studies with four different halogen bond donors at 1:1, 2:1, and 3:1 ratios.
• Analysis of binding energies and additivity of interactions.
• Local mode analysis to differentiate halogen and hydrogen bonding contributions.

Main Results:

• Substituted g-C3N4 units effectively act as halogen bond acceptors.
• Complexes formed showed significant additivity (≥90%) in binding energies for 1:1 and 2:1 complexes.
• The presence of stabilizing hydrogen bonding sites was observed, influenced by the position of XB donor attachment.
• Local mode analysis confirmed the dominance of halogen bonding interactions.

Conclusions:

• Functionalized g-C3N4 is a promising platform for developing halogen bond-based supramolecular assemblies.
• The synergistic interplay of halogen and hydrogen bonding enhances complex stability.
• These findings open avenues for designing novel functional materials utilizing halogen bonding.