ADVANCED ROTATIONAL ISOMERIC STATE SCHEME FOR MOLECULAR DESIGN OF ORGANIC AND POLMYERIC MATERIALS

在这个项目中，我们通过以下三个主题开发了一种先进的旋转异构态（RIS）方案，用于有机和聚合物材料的分子设计。(1)制备了6个具有不同构型序列的聚环氧丙烷二聚体模型化合物，并通过碳-13核磁共振进行了表征。观察到的化学位移，实验分配给组分碳原子，很好地再现RIS方案结合取代基效应。理论与实验的一致性表明了计算中所用构象能的有效性，分子内（C-H） O吸引的存在，以及RIS方案对化学位移评价的适用性。(2)采用静态光散射法和排粒径色谱-多通道激光散射法对聚甲基正丙基硅烷、聚二正丁基硅烷和聚二正己基硅烷的无扰动链尺寸进行了评价。对于单个聚合物，从分子动力学模拟中确定了包括主链和侧链相互作用的构象能。RIS方案利用由此确定的构象能很好地再现了所观察到的特征比。因此，我们开发了一种具有长侧链的聚合物构象分析方法。(3)研究了链分子（如正构烷烃和醚）在向列相溶剂中溶解的构象和取向特征，以及以六边形、层状和反六边形聚集体结合的两亲分子。采用RIS格式和最大熵法模拟了氘核磁共振四极分裂和质子-质子偶极耦合。我们建立了一种在各向异性场中链状分子构象分析的方法。

In this project, we have developed an advanced rotational isomeric state (RIS) scheme for molecular design of organic and polymeric materials through the following three subjects.(1) Six dimeric model compounds of poly (propylene oxide), having different configurational sequences, were prepared, and investigated by carbon-13 NMR.The observed chemical shifts, assigned experimentally to the component carbon atoms, were well reproduced by the RIS scheme combined with substituent effects. The agreement between theory and experiment shows the validity of the conformational energies used in the calculations, the presence of the intramolecular (C-H)…O attraction, and the applicability of the RIS scheme to chemical-shift evaluation.(2) Unperturbed chain dimensions of poly (methyl n-propylsilane), poly (di-n-butylsilane), and poly (di-n-hexylsilane) were evaluated by static light scattering and size-exclusion chromatography-multichannel laser light scattering. For individual polymers, conformational energies including interactions of both main and side chains were determined from molecular dynamics simulations. The observed characteristic ratios were well reproduced by the RIS scheme using the conformational energies thus determined. Thus, we have developed a method for conformational analysis of polymers with long side chains.(3) Conformational and orientational characteristics of chain molecules such as n-alkanes and ethers dissolved in nematic solvents and amphiphilic molecules incorporated in hexagonal, lamellar, and reversed hexagonal aggregates have been investigated. Deuterium NMR quadrupolar splittings and proton-proton dipolar couplings were simulated by a combined use of the RIS scheme and the maximum entropy method. We have established a methodology for conformational analysis of chain molecules in anisotropic fields.