1-(2-Methyl-5-nitro-phenyl)guanidinium picrate

Area of Science:

• Crystallography
• Supramolecular Chemistry
• Computational Chemistry

Background:

• Guanidinium salts are important in various chemical applications.
• Picrate anions are known for their strong interactions.
• Understanding crystal packing is crucial for material properties.

Purpose of the Study:

• To elucidate the crystal structure of the guanidinium picrate salt.
• To analyze the hydrogen bonding and intermolecular interactions within the crystal lattice.
• To compare the experimental crystal structure with computationally derived models.

Main Methods:

• Single-crystal X-ray diffraction was used to determine the crystal structure.
• Analysis of hydrogen bonding networks, including three-centre/bifurcated bonds.
• Density Functional Theory (DFT) calculations for geometry optimization and comparison.

Main Results:

• The crystal structure reveals extensive hydrogen bonding between the guanidinium cation and picrate anion.
• Key interactions include N(+)-H⋯O(-), N-H⋯O, C-H⋯O bonds, and two three-centre/bifurcated bonds.
• Significant π-π stacking interactions were observed with specific centroid-to-centroid distances and slippage angles.
• Conformational discrepancies exist between the experimental structure and DFT-optimized models.

Conclusions:

• The crystal packing is dominated by a complex network of hydrogen bonds and π-π interactions.
• The study highlights the importance of experimental crystallographic data for validating computational models.
• Observed conformational differences suggest limitations in current DFT methods for this specific system.