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Published on: July 30, 2017
2,3-Diamino-pyridinium benzoate
Kasthuri Balasubramani1, Hoong-Kun Fun
1X-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia.
Summary
This study details the crystal structure of a compound formed by 2,3-diaminopyridinium cations and benzoate anions. Hydrogen bonds and pi-pi interactions create a 2D network, revealing specific hydrogen bonding motifs.
Area of Science:
- Crystallography
- Supramolecular Chemistry
- Organic Chemistry
Background:
- Understanding the self-assembly of organic molecules is crucial for designing new materials.
- Crystal engineering relies on non-covalent interactions to control molecular arrangements.
- Protonation of heterocyclic amines can significantly alter their intermolecular interactions.
Purpose of the Study:
- To characterize the crystal structure of the 2,3-diaminopyridinium benzoate salt.
- To investigate the role of hydrogen bonding and pi-pi interactions in forming extended structures.
- To identify and describe the supramolecular motifs present in the crystal lattice.
Main Methods:
- Single-crystal X-ray diffraction was employed to determine the three-dimensional structure.
- Analysis of intermolecular distances and angles identified hydrogen bonds and pi-pi stacking.
- Topological analysis was used to classify the observed hydrogen-bonding patterns.
Main Results:
- The crystal structure reveals protonation of the pyridine nitrogen in the 2,3-diaminopyridinium cation.
- The benzoate anion exhibits a twist of the carboxylate group (10.91°).
- A two-dimensional network is formed via N-H···O hydrogen bonds and pyridinium ring pi-pi interactions (centroid-centroid distance 3.6467 Å).
- Specific hydrogen bond ring motifs, R(2)(2)(8) and R(2)(1)(7), were identified.
Conclusions:
- The crystal packing is governed by a combination of hydrogen bonding and pi-pi interactions.
- The identified supramolecular motifs provide insights into the directional bonding preferences of the components.
- This structural characterization contributes to the understanding of organic salt crystal engineering.
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