Cameron T Stanley, Grossert J Stuart, Maheux Chad R, Alarcon Idralyn Q, Copeland Catherine R, Linden Anthony
Department of Chemistry, Dalhousie University, PO Box 15000, Halifax, Nova Scotia, Canada B3H 4R2.
Science and Engineering Directorate, Canada Border Services Agency, 79 Bentley Avenue, Ottawa, Ontario, Canada K2E 6T7.
Acta Crystallogr C Struct Chem. 2015 Apr;71(Pt 4):266-70. doi: 10.1107/S2053229615004295. Epub 2015 Mar 10.
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 308 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 52 kJ mol(-1) above that of polymorph (B).
报道了娱乐性药物乙酮盐酸盐C12H16NO3(+)·Cl(-)的第二种多晶型物[系统名称：(±)-2-乙铵基-1-(3,4-亚甲基二氧苯基)丙烷-1-酮氯化物]。这种多晶型物，记为晶型(A)，出现在308 K以上进行的结晶过程中。最初报道的晶型(B)[伍德等人(2015年)。《晶体学报》C71卷，32 - 38页]在室温下优先结晶。两种晶型中阳离子的构象通过连接侧链与芳环的C - C键旋转180°而不同。氢键将两种晶型中的阳离子和阴离子连接成类似的延伸链，其中任何一条链仅包含手性阳离子的单一对映体，但离子的堆积方式不同。在晶型(A)中，相邻链的芳环相互交错，但如果相邻链包含相同或相反对映体的阳离子，则堆积效果同样良好。其结果是结构中出现近乎完美的倒易孪生。在晶型(B)中，相邻链总是倒易的，导致形成一个中心对称的空间群。通过密度泛函理论(DFT)、晶格能计算以及对堆积紧密性的考虑，研究了多晶型物在略有不同温度下结晶的原因。多晶型物(A)的晶格自由能(ΔG)比多晶型物(B)的晶格自由能高出约52 kJ mol(-1)。
