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首页> 外文期刊>Crystal growth & design >Mechanistic flexibility of solvent-assisted solid-to-solid polymorphic transition causing preferential enrichment: Significant contribution of pi/pi and CH/pi interactions as well as hydrogen bonds
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Mechanistic flexibility of solvent-assisted solid-to-solid polymorphic transition causing preferential enrichment: Significant contribution of pi/pi and CH/pi interactions as well as hydrogen bonds

机译：溶剂辅助固-固多晶型转变引起优先富集的机制柔性：pi / pi和CH / pi相互作用以及氢键的重要贡献

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A new mode of solvent-assisted solid-to-solid polymorphic transformation of the first-formed and metastable gamma-form into a stable, new alpha(1),-form, which Occurs during crystallization from individual supersaturated EtOH solutions of a series of (+/-)-[2-[4-(2-hydroxy-3-phenoxypropoxy)phenylearbamoyl]ethyl]trimethylammonium p-halobenzenesulfonates [(+/-)-1] has been found to cause an unusual symmetry-breaking enantiomeric resolution phenomenon called preferential enrichment. This polymorphic transition has been followed by the in situ attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) (ReactIR) measurement of the crystallization mixture and differential scanning calorimetry (DSC) analysis of the deposited crystals. The crystal structures with the alpha(1)-form have been solved either by X-ray crystallographic analysis of the single crystal or by the direct-space approach employing the Monte Carlo method with the subsequent Rietveld refinement from powder X-ray diffraction data of the powder sample. By comparison of the supramolecular structure characteristic of the metastable gamma-form with that of the stable cc,form, the mechanism of this polymorphic transition has been interpreted in terms of a new type of rearrangement of weak intermolecular interactions caused by slight molecular movement inside the crystal lattice, in which intermolecular pi/pi and CH/pi interactions as well as hydrogen bonds prominently control the crystal structure. This finding shows the flexibility in the mode of polymorphic transition inducing preferential enrichment.
机译：一种新的溶剂辅助固-固多晶型新模式，该模式将先形成的亚稳态γ形式转变为稳定的新α（1）形式，该形式在从一系列以下各式各样的过饱和EtOH溶液中结晶时发生（+/-）-[2- [4-（2-（3-羟基-3-苯氧基丙氧基）苯基earbamoyl]乙基]三甲基铵对卤代苯磺酸盐[（+/-）-1]已导致不寻常的破坏对称性的对映体拆分这种现象称为优先富集。此多态转变之后是原位衰减的全反射傅立叶变换红外光谱（ATR-FTIR）（ReactIR）测量结晶混合物和差示扫描量热法（DSC）分析沉积的晶体。通过单晶的X射线晶体学分析或采用蒙特卡罗方法的直接空间方法以及随后的Rietveld精炼方法，通过粉末X射线衍射数据可解决具有单晶的X射线晶体学问题。粉末样品。通过比较亚稳态γ形式与稳定cc形式的超分子结构特征，这种多态性转变的机理已被解释为一种新型的弱分子间相互作用的重排，这种弱分子间相互作用是由分子内部轻微的分子运动引起的。晶格，其中分子间pi / pi和CH / pi相互作用以及氢键显着控制晶体结构。该发现显示了在诱导优先富集的多态转变模式中的灵活性。

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