Novel local D-A interactions and physical properties in organic mixed crystals

研究了有机化合物混晶中的局域D-A相互作用和某些物理化学性质。以三苯并三苯醚、天青烯、4-取代苯甲醇和烷基脲为原料，探索了一种制备三苯二酚/三苯二酚混晶的新方法。测定了双(溴甲基)三丁三烯(bi-BrMe-TPQ)及其几种笼合物的晶体结构。该化合物与双(溴甲基)三苯基对苯二酚的混晶(bi-BrMe-TPHQ)表现出局部D-A相互作用，发现了四元环型氢键体系和相变。6，7-二甲氧基三苯三烯的晶体结构表明，它不能形成TPQ/TPHQ类型的混晶。5，12-dihydro-o-5，12-benzenonaphthacne-1，4-dione的X射线结构表明它与苯形成包合物，这一结果表明，通过改变客体从苯到其他甲苯，可以在混合晶体中发生局部D-A相互作用。对于对取代苯甲醇的混合晶体，详细研究了相变特征的组成依赖关系以及同位素效应对相变行为的影响。这些结果有助于阐明该化合物的转变机理。在一系列烷基化合物中，辛基尿素表现出一种新的相变，并伴随着很大的热变。辛基和庚基尿素的混合晶体表现出非常依赖于组成的转变特征，这为转变机理提供了有用的信息。

Local D-A interactions and some physical-chemical properties in mixed crystals of organic compounds were investigated. The materials studies were derivatives of triptycene, azulene, 4-substitutedbenzyl alcohols and alkyl urea.A new method of preparation of triptycenequinone (TPQ)/triptycenehydroquinone (TPHQ) mixed crystal was found. Crystal structures were determined for bis-(Bromomethyl)triptycene (bis-BrMe-TPQ) and its several clathrates. A mixed crystal of the compound with bis-(bromomethyl)triptycenehydroquinone (bis-BrMe-TPHQ) exhibited local D-A interaction.Four membered ring type H-bond systems and phase transition were found for bis-(hydroxy)triptycenes. From the knowledge of the crystal structure, an interesting dielectric property is expected for its mixed crystal with hydroxytriptycene.The crystal structure of 6,7-dimethoxytriptycene suggests that it cannot form a TPQ/TPHQ type mixed crystal. X-ray structure of 5,12-dihydro-o-5,12-benzenonaphthacne-1,4-dione revealed the presence of its clathrate with benzene and this result indicates that a local D-A interaction in a mixed crystal would be possible by changing the guest from benzene to other methyl-benzenes.For mixed crystals of p-substitutedbenzyl alcohols, composition dependence of the characteristics of the phase transitions, as well as an isotope effect on the transition behavior, were investigated in detail. These results contributed to elucidate the transition mechanism of the compounds.Among a series of alkyl-ures, octyl-urea exhibited a novel phase transition accompanied by a very large enthalpy change. Mixed crystals of octyl- and heptyl-urea were found to show a transition characteristic that was very dependent on the composition, giving useful information on the transition mechanism.