Bis(2-carboxy-anilinium) sulfate monohydrate

Area of Science:

• Crystallography
• Molecular Chemistry
• Supramolecular Chemistry

Background:

• Understanding the precise arrangement of atoms and molecules in crystalline solids is crucial for predicting material properties.
• Hydrogen bonding and π-π stacking are fundamental non-covalent interactions that dictate crystal packing and stability.
• Sulfate ions can exhibit disorder in crystal structures, impacting the overall network of interactions.

Purpose of the Study:

• To elucidate the detailed crystal structure of the hydrated molecular salt, 2C(7)H(8)NO(2)(+)·SO(4)(2-)·H(2)O.
• To investigate the role of intramolecular hydrogen bonding in stabilizing the cation.
• To characterize the disorder of the sulfate ion and its potential influence on hydrogen bonding networks.

Main Methods:

• Single-crystal X-ray diffraction was employed to determine the three-dimensional molecular structure.
• Analysis of bond lengths, bond angles, and intermolecular distances to identify key interactions.
• Displacement parameter analysis was used to model the disorder of the sulfate ion.

Main Results:

• The crystal structure reveals the presence of intramolecular N-H⋯O hydrogen bonds stabilizing each cation.
• The sulfate ion (SO(4)(2-)) exhibits positional disorder over two sites with a specific occupancy ratio.
• Aromatic π-π stacking interactions and C-H⋯π interactions were identified, contributing to the crystal packing.

Conclusions:

• The crystal structure of the hydrated molecular salt is characterized by specific hydrogen bonding and π-stacking interactions.
• Sulfate ion disorder appears to facilitate optimal hydrogen bond acceptance from the cations.
• These findings contribute to the understanding of crystal engineering principles for molecular salts.