Effect of Structurally Similar Additives on Crystal Habit of Organic Molecular Crystals at Low Supersaturation
Effect of Structurally Similar Additives on Crystal Habit of Organic Molecular Crystals at Low Supersaturation
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DOI：
10.1021/cg3010618
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发表时间：
2013-04-01
影响因子：
3.8
通讯作者：
Doherty, Michael F.
中科院分区：
文献类型：
--
作者：
Kuvadia, Zubin B.;Doherty, Michael F.
外来分子如添加剂或杂质可通过破坏生长机制和抑制某些晶面的生长速率而在很大程度上影响晶体形态。添加剂可以是前一反应步骤的副产物，或者它们可以被特别设计以获得用于特定应用的特定晶体形态。由于结构相似的添加剂的特定化学结构，它们只能以某些构型结合或锁定在原始晶格中;因此，只有一些晶面能够识别这些添加剂分子。一旦附着，它们会干扰旋转生长螺旋的第一圈，从而减缓面部的生长速度。在这篇文章中，我们开发了一个通用的概率方案，定量估计冒名顶替者识别每个晶面使用平均场理论和构型能量最小化的组合。在此认识的基础上，计算了杂质对螺旋第一圈的机械效应，从而计算了修改后的生长速率和修改后的晶体习性。这些概念被推广到所有的分子晶体，包括非中心对称的分子。我们证明了该模型的适用性，通过正确预测实验形态的α-甘氨酸与L-丙氨酸杂质和对乙酰氨基酚与p-乙酰氧基乙酰苯胺杂质从水中生长。
Foreign molecules such as additives or impurities may influence crystal morphology to a significant extent by disrupting the growth mechanism and inhibiting the growth rate of certain crystal faces. The additives can be byproducts of a preceding reaction step, or they could be specially designed to obtain specific crystal morphologies for particular applications. Because of the specific chemical structure of structurally similar additives, they can incorporate or lock into the original lattice only in certain configurations; hence, only some of the crystal faces are able to recognize these additive molecules. Once attached, they interfere with the first turn of a rotating growth spiral and hence slow down the growth rate of the face. In this article, we develop a generic probabilistic scheme for quantitatively estimating imposter recognition on each crystal face using a combination of mean field theory and configurational energy minimization. On the basis of this recognition, the mechanistic effect of an impurity on the first turn of the spiral and hence the modified growth rates and modified crystal habits are computed. These concepts are generalized for all molecular crystals, including non-centrosymmetric molecules. We demonstrate the applicability of the model by correctly predicting the experimental morphologies of alpha-glycine with L-alanine impurity and paracetamol with p-acetoxyacetanilide impurity grown from water.