Work

Synthesis and structure of 2-amino-4-methylpyridin-1-ium hydrogen squarate

Year: 2025

Type: article

Abstract: The title salt (systematic name: 2-amino-4-methylpyridin-1-ium 2-hydroxy-3,4-dioxocyclobut-1-en-1-olate), C 6 H 9 N 2 + ·C 4 HO 4 − , was obtained by the proton-transfer reaction between 2-amino-4-methylpyridine and squaric acid in aqueous solution: protonation occurs at the pyridine nitrogen atom, while squaric acid is singly deprotonated. In the crystal, the cations and anions are linked by N—H...O, O—H...O, and C—H...O hydrogen bonds, forming infinite layers. These layers are consolidated by π–π stacking interactions, resulting in a columnar packing arrangement. Hirshfeld surface analysis reveals that O...H/H...O contacts dominate the intermolecular interactions, consistent with the hydrogen-bonding network observed in the crystal structure.

Source: Acta Crystallographica Section E Crystallographic Communications

DOI: 10.1107/s205698902501045x

Authors: Vanitha Vetrivel, Thangavelu Balakrishnan, Nishandhini Marimuthu

Institutions: Bharathidasan University, PG&E Corporation (United States), Vels University

Language: English

Topic: Crystal structures of chemical compounds

Subfield: Inorganic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $500

Funder: Indian Institute of Technology Madras