The Preparation and Study of Novel Ligand Systems

在有机和高分子化学计划的支持下， 伦敦大学化学系的兰多夫P. Thummel教授 休斯顿大学，研究了 新的配体系统。 Thummel教授探索了立体化学 二齿配体内不对称取代的结果， 重点是这种取代在空间和电子效应， 三（联吡啶）的面式和立体式非对映异构体的形成 钌（II）的络合物。 通过合成一系列配体 与9-（二-2 '-吡啶基）亚甲基芴有关，被设计为经历 光诱导金属-配体结合后围绕中心π键的旋转 电荷转移，从而对内部返回到 基态，Thummel教授正在研究 长寿命的光激发态 相关配体允许评估 配体氧化态对两个分子间电子传递影响 结合的金属离子，而基于芘的配体的络合物提供 可以观察室温发射。 金属离子的物理和化学性质可能会改变 通过将它们捕获在分子结构中， 影响所选属性。 教授兰多夫P. Thummel， 休斯顿大学化学系，由 有机和高分子化学计划，他的研究 分子的合成和研究，旨在影响化学 金属配合物与金属配合物相互作用产生的过程 光 这样的光过程导致电子从电子转移到电子束。 金属到支持分子结构，并通过设计这个 结构在这种电子作用下经历显著几何变化 转移，Thummel教授试图稳定光诱导的 “兴奋状态”。 相关研究允许评估对 两个金属离子之间的电子通信性质的变化 连接它们的分子群。 这些研究涉及 关于光诱导电子转移的基本问题， 与从阳光中获取能量直接相关。

With the support of the Organic and Macromolecular Chemistry Program, Professor Randolph P. Thummel, of the Department of Chemistry at the University of Houston, investigates the preparation and properties of novel ligand systems. Professor Thummel explores the stereochemical consequences of unsymmetrical substitution within bidentate ligands, focusing on the steric and electronic effects of such substitution in the formation of facial and meridional diastereomers of tris(bipyridyl) complexes of ruthenium(II). Through the synthesis of a series of ligands related to 9-(di-2'-pyridyl)methylenefluorene, designed to undergo rotation about the central pi bond following photoinduced metal-to-ligand charge transfer and thereby present a barrier to internal return to the ground state, Professor Thummel is investigating the generation of long-lived photoexcited states. Related ligands permit assessment of the impact of ligand oxidation state on electronic communication between two bound metal ions, while complexes of pyrene-based ligands offer the possibility to observe room temperature emission. The physical and chemical properties of metal ions may be altered dramatically by capturing them within a molecular structure designed to impact chosen properties. Professor Randolph P. Thummel, of the Department of Chemistry at the University of Houston, is supported by the Organic and Macromolecular Chemistry Program for his investigations of the synthesis and study of molecules designed to affect the chemical processes resulting from the interaction of their metal complexes with light. Such photoprocesses lead to the transfer of an electron from the metal to the supporting molecular structure, and by designing this structure to undergo a significant change in geometry upon such electron transfer, Professor Thummel attempts to stabilize the photoinduced `excited state.` Related studies permit assessment of the effect on the electronic communication between two metal ions of a change in the nature of a molecular grouping which bridges them. These studies address fundamental issues regarding photoinduced electron transfer and are directly related to the harvesting of energy from sunlight.