Photochromic Ruthenium Sulfoxide Complexes: Ultrafast Spectroscopy and Photomechanical Effects

化学分部的化学结构、动力学和机制项目支持俄亥俄大学的Jeffrey Rack教授进行光致变色亚砜钌配合物的开发研究。这些化合物的光致变色是由同分异构体之间的转化引起的，在同分异构体中，亚砜通过硫与钌结合，在同分异构体中，亚砜通过氧与钌结合。这些化合物的新例子将被合成以测试位阻配体对异构化激发态速率常数的作用。飞秒瞬态吸收光谱将用于确定速率常数及其波长，溶剂和温度的依赖关系。在飞秒和皮秒时间尺度上识别中间体是一个重要的目标。具有双色可逆光致变色特性的配合物将被掺入具有照相效果的聚合物中。这种效应是非常罕见的，将开发一种新的方法来测量具有光电效应的聚合物中的应变。与此项目相关的学生将在无机、物理、分析和有机化学领域接受培训。该项目的多学科性质将要求学生了解不同研究领域的文献贡献。弱势群体的参与也是这个项目的真正目标。俄亥俄大学位于俄亥俄州阿巴拉契亚地区的农村，长期经济萧条地区。俄亥俄大学坚定地致力于教育和培训学生群体，其低收入第一代大学生的比例明显高于全国普遍水平。事实上，在化学和生物化学系进行研究的本科生中，40%来自阿巴拉契亚29个县之一。与此项目相关的学生将参与许多部门、学院、大学和社区的外展和互动项目。

The Chemical Structure, Dynamics and Mechanisms Program of the Chemistry Division supports Professor Jeffrey Rack at Ohio University for studies into the development of photochromic ruthenium sulfoxide complexes. Photochromism in these compounds arises from conversion between isomers in which the sulfoxide is bonded to the ruthenium through sulfur and ones in which the sulfoxide is attached to the ruthenium through oxygen. New examples of these compounds will be synthesized to test the role of sterically-hindered ligands on the excited state rate constant for the isomerization. Femtosecond transient absorption spectroscopy will be employed to determine the rate constants along with their wavelength, solvent and temperature dependence. Identification of intermediates on the femtosecond and picosecond timescale is an important goal. Complexes that feature two-color reversible photochromism will be incorporated into polymers that will feature photomechanical effects. Such effects are exceptionally rare and a new procedure for measuring strain in polymers featuring photomechanical effects will be developed.Students associated with this project will be trained in the areas of inorganic, physical, analytical and organic chemistry. The multi-disciplinary nature of the project will demand that the student be aware of literature contributions in disparate research areas. Involvement of underrepresented groups is also a genuine goal of this project. Ohio University is located in Athens, OH a rural, chronically economically depressed area in Appalachia. Ohio University is deeply committed to the education and training of a student population with a significantly higher than national prevalence of low-income, first generation college students. Indeed, of those undergraduate students performing research in the Department of Chemistry and Biochemistry, 40% are from one of the 29 counties in Appalachia. The students associated with this project will be involved in a number of divisional, departmental, College, University and Community outreach and interactive programs.