Kinetic and thermodynamic conformational polymorphs of bis(p-tolyl) ketone p-tosylhydrazone:: The Curtin-Hammett principle in crystallization
Kinetic and thermodynamic conformational polymorphs of bis(p-tolyl) ketone p-tosylhydrazone:: The Curtin-Hammett principle in crystallization
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DOI：
10.1021/cg070542t
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发表时间：
2007-10-01
影响因子：
3.8
通讯作者：
Nangia, Ashwini
中科院分区：
文献类型：
--
作者：
Roy, Saikat;Nangia, Ashwini
二(对甲苯基)酮对甲苯基肼(2)在不同条件下结晶为1-3种构象多晶型。晶型I的晶体结构为N-H中心点O=S二聚体合成子，而晶型2和3虽然含有SO2NH基团，但没有强氢键。根据低能量、高熔点和高密度的标准，将晶型I和3指定为动力学和热力学形式。对分子内能(E-conf)和分子间能(U-latt)的计算表明，晶型I和晶型3之间的晶体能量差(E-TOTAL)为2.54千卡·摩尔(-1)，而亚稳和消失的晶型2具有更高的能量，为8.71千卡·摩尔~(-1)。磺酰胺2是一种罕见的多晶型簇合物，其中强氢键稳定了动力学形式I，而热力学多晶型2具有良好的紧密堆积，但没有氢键。提出了一个与结构、热化学和计算数据相一致的构象I和构象3晶型结晶的Curtin-Hammett能量分布。将甲苯基化合物2中的氢键与对位不同的其他二苯甲酮肼类化合物(如H、F、Cl、Br.)进行比较。双分子N-H中心点O=S二聚体存在于晶体结构3-6中，也存在于2的CH2Cl2溶剂以及氯5和溴6肼的苯溶剂中。
Bis(p-tolyl) ketone p-tosylhydrazone (2) crystallized as three conformational polymorphs, forms 1-3, under different conditions. The crystal structure of form I has an N-H center dot center dot center dot O=S dimer synthon, but forms 2 and 3 have no strong hydrogen bonds even though the molecule contains an SO2NH group. Polymorphs I and 3 are assigned as kinetic and thermodynamic forms on the basis of the criteria of lower energy, higher melting point, and higher density for the latter modification. Calculation of both intramolecular (E-conf) and intermolecular energy (U-latt) gave a crystal energy difference (Delta E-total) of 2.54 kcal mol(-1) between forms I and 3, whereas metastable and disappearing form 2 has much a higher energy of 8.71 kcal mol-1. Sulfonamide 2 is a rare example of a polymorph cluster wherein strong hydrogen bonds stabilize kinetic form I whereas thermodynamic polymorph 2 has excellent close packing but no hydrogen bonds. A Curtin-Hammett energy profile for the crystallization of conformational polymorphs I and 3 is proposed that is consistent with structural, thermochemical, and computational data. Hydrogen bonding in tolyl compound 2 is compared with other benzophenone hydrazones varying at the para-position (e.g., H, F, Cl, Br). The bimolecular N-H center dot center dot center dot O=S dimer is present in crystal structures 3-6 as well as in the CH2Cl2 solvate of 2 and benzene solvates of chloro 5 and bromo 6 hydrazones.