Mechanism of formation of chiral crystals studied by using induced-chiral molecule as a probe

本文以酒石酸、苯丙二酸和氯硝基苯甲酸为模型化合物，研究了由非手性分子组成的手性晶体的形成机理。前两种化合物的酸性阴离子是光学活性的。最后一种在晶化时具有轴手性。我们制备了上述化合物与胺、吡啶和氨基酸衍生物的盐或分子间化合物，并用单晶X-射线衍射法测定了它们的晶体结构。此外，我们还测定了氯冉酸与胺、吡啶和氨基酸衍生物的盐或分子间化合物的晶体结构，以研究它们的氢键构型和氢键中的质子转移机制，部分结果已发表在国际晶体学杂志上。已发表的晶体结构为：（1）2-吡啶酮-丙醇二酸（1/1），3-羟基吡啶氢丙醇二酸盐和4-羟基吡啶氢丙醇二酸盐，（2）苯并咪唑氢苯丙二酸盐，（3）3，5-二甲基吡啶-2-氯-4-硝基苯甲酸盐-2-氯-4-硝基苯甲酸（1/1/1），3-氰基吡啶-2-氯-4-硝基苯甲酸（1/1），（4）苯并咪唑-2-氯-4-硝基苯甲酸盐。（4）氯冉酸盐与羧基吡啶鎓、胞嘧啶鎓、吩嗪、吡啶鎓、哌啶鎓、吡咯烷鎓、甲基吡唑鎓、四氢喹啉鎓和三甲基吡啶鎓离子。

Tartornic acid, phenylmaronic acid and chloronitrobenzoic acid have been undertaken as model compounds in order to investigate the mechanism of formation of chiral crystals which are composed of achiral molecules. The acidic anions of the first two compounds are optically active. The last one has an axial-chirality when it is crystallized. We have prepared salts or intermolecular compounds of the above compounds with amine, pyridine and amino acid derivatives, and determined the crystal structures by single crystal X-ray diffraction. Furthermore, we have determined crystal structures of salts or intermolecular compounds of chloranilic acid with amine, pyridine and amino acid derivatives in order to investigate their hydrogen bond scheme and the proton transfer mechanism in the hydrogen bond.Part of the results have already been published in the international crystallographic journals. The published crystal structures are: (1) 2-pyridone-tartronic acid (1/1), 3-hydroxypyridinium hydrogen tartronate and 4-hydroxypyridinium hydrogen tartronate; (2) benzimidazolium hydrogen phenylmalonate; (3) 3,5-lutidinium-2-chloro-4-nitrobenzoate-2-chloro-4-nitrobenzoic acid (1/1/1), 3-cyanopyridine-2-chloro-4-nitrobenzoic acid (1/1); (4) chloranilate with carboxypyridinium, cytosinium, phenazine, picolinium, piperidinium, pyrrolidinium, methylpyrazolium, tetrahydroquinolinium and trimethylpyridinium ion.