3,4-Diaminopyridinium 2-carboxy-4,6-dinitrophenolate.

Area of Science:

• Crystallography
• Supramolecular Chemistry
• Organic Chemistry

Background:

• 3,4-diaminopyridine is a versatile organic compound with applications in coordination chemistry and materials science.
• Salicylic acid derivatives, particularly dinitrosalicylic acid, are used in analytical chemistry and as precursors for energetic materials.
• Understanding the solid-state structures of organic salts is crucial for predicting their physical and chemical properties.

Purpose of the Study:

• To elucidate the crystal structure of the 3,4-diaminopyridine 3,5-dinitrosalicylate salt.
• To investigate the hydrogen bonding interactions and molecular arrangement in the solid state.
• To characterize the disorder within the anion component of the salt.

Main Methods:

• Single-crystal X-ray diffraction was employed to determine the molecular and crystal structure.
• The crystal structure was solved and refined using standard crystallographic software.
• Intermolecular interactions, including hydrogen bonds, were analyzed using crystallographic data.

Main Results:

• The salt crystallizes with the formula [C(5)H(8)N(3)](+)[C(7)H(3)N(2)O(7)](-), indicating protonation of the pyridine nitrogen in 3,4-diaminopyridine.
• The 3,5-dinitrosalicylate anion exhibits significant whole-molecule disorder, adopting two distinct orientations with a refined occupancy ratio.
• A three-dimensional network is formed through extensive intermolecular hydrogen bonding, including N-H···O and C-H···O interactions between cations and anions.

Conclusions:

• The crystal structure provides detailed insights into the protonation state and intermolecular interactions of this organic salt.
• The observed anion disorder has implications for the material's properties and packing efficiency.
• The formation of a robust 3D hydrogen-bonded network highlights the importance of non-covalent interactions in directing crystal assembly.