Quinine di-hydro-chloride hemihydrate

Area of Science:

• Crystallography
• Supramolecular Chemistry
• Organic Chemistry

Background:

• Understanding the intermolecular forces governing crystal packing is crucial for materials science.
• Non-covalent interactions dictate the self-assembly and properties of molecular solids.
• The title compound, 2C20H26N2O2 2+·4Cl−·H2O, presents an opportunity to study these interactions in a complex organic cation.

Purpose of the Study:

• To elucidate the crystal structure of the title compound.
• To identify and analyze the non-covalent interactions present in the crystal lattice.
• To investigate the nature and extent of observed molecular disorder.

Main Methods:

• Single-crystal X-ray diffraction was employed to determine the three-dimensional crystal structure.
• Analysis of the crystal structure involved identifying hydrogen bonds and π-π stacking interactions.
• Disorder in the ethylene double bond was modeled and analyzed.

Main Results:

• The crystal structure is stabilized by a network of hydrogen bonds between the organic cation, chloride anions, and water molecules.
• π-π interactions between the aromatic quinolinium moieties contribute to the long-range ordering of the crystal.
• A significant finding was the presence of positional disorder in one of the ethylene double bonds, affecting adjacent atoms.

Conclusions:

• The crystal structure of the title compound is characterized by a rich interplay of hydrogen bonding and π-π stacking interactions.
• These non-covalent forces are key to the observed molecular arrangement and crystal packing.
• The identified ethylene double bond disorder provides insights into the dynamic behavior of molecules in the solid state.