3-Hydroxy-pyridinium hydrogen chloranilate monohydrate

Area of Science:

• Crystal Engineering
• Supramolecular Chemistry
• Materials Science

Background:

• Understanding the self-assembly of organic molecules is crucial for designing new materials.
• Hydrogen bonding plays a significant role in directing crystal packing and molecular architecture.
• Salt hydrates offer versatile platforms for exploring intermolecular interactions.

Purpose of the Study:

• To elucidate the crystal structure of a specific salt hydrate (C(5)H(6)NO(+)·C(6)HCl(2)O(4) (-)·H(2)O).
• To investigate the nature and role of intermolecular interactions in stabilizing the crystal lattice.
• To characterize the spatial arrangement of the organic cations, anions, and water molecules.

Main Methods:

• Single-crystal X-ray diffraction was employed to determine the three-dimensional crystal structure.
• Analysis of hydrogen bonding (O-H⋯O, N-H⋯O) and C-H⋯O contacts was performed.
• Geometric parameters, including dihedral angles, were calculated to describe the molecular and crystal packing.

Main Results:

• The salt hydrate crystallizes in a distinct double-tape structure extending along the c axis.
• The structure is stabilized by a network of O-H⋯O, N-H⋯O hydrogen bonds, and C-H⋯O contacts.
• The pyridinium and chloranilate rings exhibit near-coplanarity within the tapes, with a small dihedral angle of 2.35(7)°.

Conclusions:

• The identified double-tape motif represents a novel supramolecular assembly in this salt hydrate.
• The interplay of hydrogen bonding and π-π interactions dictates the observed crystal packing.
• This structural insight contributes to the fundamental understanding of crystal engineering principles for organic salts.