Inversion twinning in a second polymorph of the hydrochloride salt of the recreational drug ethylone.
Acta Crystallogr C Struct Chem
; 71(Pt 4): 266-70, 2015 Apr.
Article
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| MEDLINE
| ID: mdl-25836283
ABSTRACT
A second polymorph of the hydrochloride salt of the recreational drug ethylone, C12H16NO3(+)·Cl(-), is reported [systematic name (±)-2-ethylammonio-1-(3,4-methylenedioxyphenyl)propane-1-one chloride]. This polymorph, denoted form (A), appears in crystallizations performed above 308â
K. The originally reported form (B) [Wood et al. (2015). Acta Cryst. C71, 32-38] crystallizes preferentially at room temperature. The conformations of the cations in the two forms differ by a 180° rotation about the C-C bond linking the side chain to the aromatic ring. Hydrogen bonding links the cations and anions in both forms into similar extended chains in which any one chain contains only a single enantiomer of the chiral cation, but the packing of the ions is different. In form (A), the aromatic rings of adjacent chains interleave, but pack equally well if neighbouring chains contain the same or opposite enantiomorph of the cation. The consequence of this is then near perfect inversion twinning in the structure. In form (B), neighbouring chains are always inverted, leading to a centrosymmetric space group. The question as to why the polymorphs crystallize at slightly different temperatures has been examined by density functional theory (DFT) and lattice energy calculations and a consideration of packing compactness. The free energy (ΔG) of the crystal lattice for polymorph (A) lies some 52â
kJâ
mol(-1) above that of polymorph (B).
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Acetona
/
Sales (Química)
/
Drogas Ilícitas
/
Etilaminas
/
Ácido Clorhídrico
Idioma:
En
Revista:
Acta Crystallogr C Struct Chem
Año:
2015
Tipo del documento:
Article