Studies of the Effect of Electron Exchange Coupling on the Photophysics and Photochemistry of Transition Metal Complexes: Discrete Molecules to Magneto-Optical Polymers

电子交换耦合对过渡金属络合物光物理和光化学影响的研究：离散分子到磁光聚合物摘要博士。McCusker由无机生物无机和有机化学计划支持，以研究交换耦合的存在如何影响金属络合物的光诱导激发态性质。 McCusker提出通过与顺磁性金属中心配位的半醌配体的系统变化来研究自由基配体和金属离子之间的分子内交换偶联。 在证明了电子交换对铬-半醌络合物基态特征的影响之后，将使用低温时间分辨吸附和时间分辨共振拉曼光谱来检查对激发态的影响。 所提出的工作的其他目标是1）测量交换耦合对配体间电子交换动力学的影响和2）检查光氧化还原活性的波长依赖性。 扩展研究将包括磁光二聚体的合成和表征。虽然顺磁中心的自旋耦合对分子物理性质的影响受到了相当大的关注，但关于这种现象如何影响分子的物理特性的信息却很少。 对交换耦合的进一步理解可能会导致分子基磁光材料的发展。

James McCuskerCHE-9729003Title: Studies of the Effect of Electron Exchange Coupling on the Photophysics and Photochemistry of Transition Metal Complexes: Discrete Molecules to Magneto-Optical PolymersAbstractDr. McCusker is supported by the Inorganic Bioinorganic and Organometallic Chemistry Program to examine how the presence of exchange coupling affects photo-induced excited-state properties of metal complexes. McCusker has proposed to study intramolecular exchange coupling, between the radical ligand and the metal ion, via the systematic variation of semiquinone ligands coordinated to paramagnetic metal centers. Having demonstrated the effect of electron exchange on ground-state characteristics of chromium-semiquinone complexes, effects upon the excited-state will be examined using low-temperature time-resolved adsorption and time-resolved resonance Raman spectroscopy. Additional goals of the proposed work are to 1) measure the effect of exchange coupling upon inter-ligand electron-exchange dynamics and 2) examine the wavelength dependence of photoredox activity. Extension studies will include the synthesis and characterization of magneto-optical dimers.While the impact of spin coupling of paramagnetic centers on the physical properties of molecules has received considerable attention, there is a paucity of information on how the photophysical characteristics of molecules are affected by this phenomenon. An increased understanding of exchange coupling may lead to the development of molecular-based magneto-optical materials.