Trihexyphenidyl hydro-chloride: a powder diffraction study.

Area of Science:

• Crystallography
• Organic Chemistry
• Materials Science

Background:

• Understanding the solid-state structure of organic salts is crucial for predicting their physical properties.
• The title compound, 1-(3-cyclo-hexyl-3-hydroxy-3-phenyl-propyl)piperidinium chloride, presents an interesting case for structural analysis due to its complex organic cation.

Purpose of the Study:

• To elucidate the crystal structure of 1-(3-cyclo-hexyl-3-hydroxy-3-phenyl-propyl)piperidinium chloride.
• To investigate the intermolecular interactions governing the solid-state packing.
• To determine the crystallization behavior and enantiomeric composition of the salt.

Main Methods:

• Single-crystal X-ray diffraction was employed to determine the three-dimensional structure.
• Analysis of hydrogen bonding (O-H⋯Cl, N-H⋯Cl) and weak C-H⋯Cl interactions.
• Characterization of the crystallization process from a racemic solution.

Main Results:

• The crystal structure reveals chair conformations for the cyclo-hexyl and piperidine rings.
• Cations and anions form chains along the c-axis via O-H⋯Cl and N-H⋯Cl hydrogen bonds.
• Weak C-H⋯Cl interactions further assemble these chains into layers parallel to the bc plane.
• The salt crystallizes in the chiral P2(1)2(1)2 space group, forming a racemic conglomerate from a racemic solution.

Conclusions:

• The crystal packing is dominated by hydrogen bonding and weaker C-H⋯Cl interactions.
• The formation of a racemic conglomerate indicates no spontaneous chiral resolution during crystallization from a racemic mixture.
• The detailed structural information provides a basis for understanding the physical properties and potential applications of this organic salt.