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首页> 外文期刊>Crystal growth & design >Polymorphs of 1?(5-Methylthiazol-2-yl)-3-phenylthiourea and Various Anion-Assisted Assemblies of Two Positional Isomers
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Polymorphs of 1?(5-Methylthiazol-2-yl)-3-phenylthiourea and Various Anion-Assisted Assemblies of Two Positional Isomers

机译：1？（5-甲基噻唑-2-基）-3-苯基硫脲的多晶型物和两个位置异构体的各种阴离子辅助组装

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Orientations of the phenyl group and the intramolecular hydrogen bond play prime roles in the packing patterns of three conformational polymorphs of an unsymmetrical thiourea derivative, 1-(5-methylthiazol-2-yl)-3-phenylthiourea (PTH1). Self-assembly of each polymorph is composed of hydrogen-bonded dimeric motifs held together in head-to-tail arrangement but packed in different manners. Each has an intramolecular N?H···N hydrogen bond between an amide N?H and the nitrogen atom of the 5-methylthiazole unit. The packing pattern of 1-(4-methylthiazol-2- yl)-3-phenylthiourea (PTH2) is composed of dimeric assemblies of PTH2 in head-to-tail fashion. PTH2 is monomorphic as there are intermolecular C?H···S interactions between a C?H bond of the phenyl ring of each molecule and the sulfur atom of the thiocarbonyl group of a neighboring molecule. Such interactions lock the orientation of phenyl group in the solid state. The syn?anti conformation across the thiourea group, originally present in the positional isomers PTH1 and PTH2, is invariably transformed to syn?syn conformation in their salts. The extent of hydration of anions in the salts of PTH1 or PTH2 is dependent on the cation as well as the anion. The chloride salt of PTH1 has a large difference in packing patterns in comparison with the corresponding chloride salt of PTH2; they also differ in the numbers of symmetry-nonequivalent molecules in their respective unit cells. The anhydrous salt of PTH1 with hydrogen bromide having a 1:1 ratio of cation and anion is formed, whereas the bromide salt of PTH2 is a hydrate of composition (HPTH2)_2(Br)_2·6H_2O. This salt has bromide?water clusters in its crystal lattice. Nitric acid reacts with PTH1 under different conditions to form hydrated or anhydrous salts. The hydrated salt (HPTH1)_2(NO_3)_2·H_2O has anions bridged by water molecules. The anhydrous nitrate salts of PTH1 and PTH2 are structurally similar in having nitrate···nitrate interactions. The deprotonation of polyacids by PTH1 and PTH2 is selective. The ability to abstract a proton from sulfuric acid to form crystalline salts by PTH1 and PTH2 differs. The sulfate salt (HPTH1)_2(SO_4) is formed by reaction of sulfuric acid with PTH1, but PTH2 forms the bisulfate salt (HPTH2)HSO_4·H_2O. PTH1 forms the corresponding dihydrogen phosphate salt upon reaction with orthophosphoric acid; the dihydrogen phosphate anions are held together in the form of cyclic hydrogen-bonded hexameric assemblies in the lattice. Water loss from the assemblies of hydrated salt was determined by thermogravimetry and differential scanning calorimetry and showed that dehydration from anion-assisted assemblies was guided by the cationic host and the type of assembly.
机译：苯基和分子内氢键的取向在不对称硫脲衍生物1-（5-甲基噻唑-2-基）-3-苯基硫脲（PTH1）的三个构象多晶型的堆积模式中起主要作用。每个多晶型物的自组装由氢键结合的二聚体基序以头尾相接但以不同方式包装而成。每一个在酰胺N 2 H和5-甲基噻唑单元的氮原子之间具有分子内的N 3 H··N氢键。 1-（4-甲基噻唑-2-基）-3-苯基硫脲（PTH2）的堆积模式由PTH2的二聚体组装而成。 PTH2是单态的，因为每个分子的苯环的C2H键与相邻分子的硫代羰基的硫原子之间存在分子间的C2H··S相互作用。这种相互作用将苯基锁定在固态状态。最初存在于位置异构体PTH1和PTH2中的整个硫脲基上的顺式构象始终不变地转化为其盐中的顺式构象。 PTH1或PTH2盐中阴离子的水合程度取决于阳离子以及阴离子。与相应的PTH2氯化物盐相比，PTH1的氯化物盐在堆积方式上有很大差异。它们在各自的晶胞中对称非等价分子的数量也不同。形成了PTH1与阳离子和阴离子的比率为1：1的溴化氢的无水盐，而PTH2的溴化物盐是组成（HPTH2）_2（Br）_2·6H_2O的水合物。这种盐的晶格中有溴化物-水团簇。硝酸在不同条件下与PTH1反应形成水合或无水盐。水合盐（HPTH1）_2（NO_3）_2·H_2O具有由水分子桥接的阴离子。 PTH1和PTH2的无水硝酸盐在结构上相似，具有硝酸盐···硝酸盐相互作用。 PTH1和PTH2对多元酸的去质子作用是选择性的。 PTH1和PTH2从硫酸中提取质子形成结晶盐的能力有所不同。硫酸盐（HPTH1）_2（SO_4）是由硫酸与PTH1反应形成的，而PTH2则形成了硫酸氢盐（HPTH2）HSO_4·H_2O。 PTH1与正磷酸反应生成相应的磷酸二氢盐;磷酸二氢根阴离子以环状氢键结合的六聚体形式存在于晶格中。通过热重分析和差示扫描量热法测定了水合盐组合物中的失水量，结果表明阳离子辅助剂和组合物类型可指导阴离子辅助组合物的脱水。

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