Crystal structures of four organic salts of trihexyphenidyl at 90 K

• Published in: Acta crystallographica. Section E, Crystallographic communications Vol. 79; no. Pt 8; pp. 730 - 735
• Main Authors: Vinaya, Basavaraju, Yeriyur B, Yathirajan, Hemmige S, Parkin, Sean
• Format: Journal Article
• Language: English
• Published: England International Union of Crystallography 01.08.2023
• Subjects: crystal structure; disorder; hydrogen bonding; non-merohedry; Research Communications; trihexyphenidyl; trihexyphenidylium cation; twinning; twinning; hydrogen bonding; disorder; trihexyphenidylium cation; trihexyphenid­yl; crystal structure; non-merohedry
• ISSN: 2056-9890; 2056-9890
• DOI: 10.1107/S2056989023005960

The syntheses and crystal structure studies of four organic salts of trihexyphenidyl, ., trihexyphenidylium [1-(3-cyclo-hexyl-3-hy-droxy-3-phenyl-prop-yl)piperidin-1-ium] 4-nitro-benzoate, C H NO ·C H NO ( ), trihexyphenidylium 4-hy-droxy-benzoate, C H NO ·C H O ( ), trihexyphenidylium 4-bromo-benzoate, C H NO ·C H BrO ( ), and trihexyphenidylium thio-phene-2-carboxyl-ate hemihydrate, 2C H NO ·2C H O S ·H O ( ), con-ducted at 90 K are described. Structures , , and are solvent free with one cation-anion pair per asymmetric unit, while crystallizes as a hemihydrate, having two cation-anion pairs and one water of crystallization in its asymmetric unit. Structures and exhibit configurational disorder of the cation. Structure also exhibits disorder, but only of the thio-phene-2-carboxyl-ate anions. Structure is a non-merohedric twin by a twofold rotation about [403]. The main supra-molecular motifs in , , and are similar (10) rings between cation-anion pairs, although their packing within the crystals is distinct. As a consequence of having two cation-anion pairs and a water mol-ecule in its asymmetric unit, the packing in is by far the most complex of the four structures, its hydrogen-bonding patterns being quite different from , , or . In all the crystals studied, N-H⋯O, O-H⋯O, and C-H⋯O inter-actions are observed, plus C-H⋯Br close contacts for .