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2-Amino-3-ammonio-pyridinium dichloride
Madhukar Hemamalini1, Hoong-Kun Fun
1X-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia.
This study details the crystal structure of diprotonated 2,3-diaminopyridine dihydrochloride. The structure reveals a 3D network formed by hydrogen bonds between cations and chloride anions, with stabilizing pi-pi interactions.
Area of Science:
- Crystallography
- Supramolecular Chemistry
- Organic Chemistry
Background:
- 2,3-diaminopyridine is a heterocyclic aromatic organic compound.
- Protonation of nitrogen-containing heterocycles can alter their chemical properties and intermolecular interactions.
- Understanding crystal structures provides insights into molecular assembly and bonding.
Purpose of the Study:
- To determine and analyze the crystal structure of diprotonated 2,3-diaminopyridine dihydrochloride.
- To investigate the intermolecular interactions stabilizing the crystal lattice.
- To characterize the role of hydrogen bonding and pi-pi interactions in the supramolecular assembly.
Main Methods:
- Single-crystal X-ray diffraction was employed to elucidate the crystal structure.
- Analysis of bond lengths, bond angles, and intermolecular distances.
- Identification and quantification of hydrogen bonds (N-H⋯Cl, C-H⋯Cl) and pi-pi interactions.
Main Results:
- The asymmetric unit contains two diprotonated 2,3-diaminopyridine cations and four chloride anions.
- A three-dimensional network is formed through extensive intermolecular N-H⋯Cl and C-H⋯Cl hydrogen bonds.
- Stabilizing pi-pi interactions between pyridinium rings were observed with a centroid-centroid distance of 3.695(1) Å.
Conclusions:
- The crystal structure of diprotonated 2,3-diaminopyridine dihydrochloride is characterized by a robust 3D network.
- Hydrogen bonding plays a crucial role in the self-assembly of the ionic compound.
- Pi-pi stacking interactions further contribute to the overall stability of the crystal lattice.
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