2-Amino-benzoxazole-oxalic acid (2/1)

Area of Science:

• Crystallography
• Supramolecular Chemistry
• Organic Chemistry

Background:

• Molecular salts are formed by the transfer of protons between acidic and basic components.
• Hydrogen bonding plays a crucial role in the self-assembly of molecular structures.
• Heterocyclic compounds are widely studied for their diverse chemical properties and applications.

Purpose of the Study:

• To investigate the structural characteristics of a novel molecular salt formed between a nitrogen-containing heterocycle and oxalic acid.
• To elucidate the role of proton transfer and hydrogen bonding in the crystal packing of the compound.
• To characterize the supramolecular architecture formed in the solid state.

Main Methods:

• Single-crystal X-ray diffraction was employed to determine the molecular and crystal structure.
• Analysis of hydrogen bonding interactions and topological features of the crystal network.
• Characterization of the proton transfer event through structural parameters.

Main Results:

• The title compound, 2C7H7N2O+·C2O42−, was identified as a 2:1 molecular salt, indicating proton transfer from oxalic acid to the heterocycle.
• N-H⋯O hydrogen bonds were observed, linking the protonated heterocycle and oxalate anions into [100] chains.
• The crystal structure exhibits specific hydrogen-bonded loops, characterized by graph set notations R22(8) and R44(14).

Conclusions:

• The study successfully characterized the formation and structure of a novel molecular salt.
• Proton transfer and directed hydrogen bonding are key factors governing the self-assembly into extended chain structures.
• The observed supramolecular motifs provide insights into crystal engineering principles for related systems.