Ultrafast time-resolved studies of reactive intermediates

在有机和大分子计划的支持下，Matthew Platz教授和他的团队计划研究重氮化合物，重氮化合物和叠氮化物（“前体”）的光化学以及卡宾和氮烯反应中间体的诞生。使用飞秒时间分辨紫外-可见和红外光谱和计算方法，他们将了解前体分子的哪种跃迁被泵浦，以及前体的哪种激发态导致碎片化，形成反应性中间体和氮。如果抽运态和解离态不相同，他们将研究它们之间的连接途径和解离过程的时间尺度。他们将验证重排可以与氮气挤出协同进行，并确定负责该过程的激发态。他们将监测热活性中间体的形成以及控制它们将热量传递给溶剂的速率的结构和环境因素，以及它们是否在松弛时重排。该小组将学习单重态活性中间体的寿命和控制它们弛豫到三重态物种的因素。这项研究有几个广泛的影响。学生接受经典有机化学以及超快光谱技术和先进计算方法的培训。学生将学习在合成化学，分析化学，超快光谱学和理论小组中工作。有机，分析和物理化学家一起工作，互相学习。从历史上看，广场实验室欢迎妇女，少数民族和多数高中学生实习生，本科生，研究生，博士后学生和访问教师。学生学习与许多种族，民族，国籍和教育水平的个人一起工作。 实验室的许多毕业生已被安置在大学，学院和高中的职位教化学，他们致力于继续这一传统。

With the support of the Organic and Macromolecular Program, Professor Matthew Platz and his group plan to study the photochemistry of diazirines, diazo compounds and azides ("precursors") and the birth of carbenes and nitrene reactive intermediates. Using femtosecond time resolved UV-Vis and IR spectroscopy and computational methods they will learn which transition of the precursor molecules is pumped and which excited state of the precursor leads to fragmentation to form a reactive intermediate and nitrogen. If the pumped state and dissociative states are not the same, they will study the pathway connecting them and the time scale of the dissociative process. They will verify that rearrangement can proceed in concert with nitrogen extrusion and identify the excited state responsible for that process. They will monitor the formation of hot reactive intermediates and the structural and environmental factors that control the rate at which they transfer heat to solvent and if they rearrange as they relax. The group will learn the lifetime of singlet reactive intermediates and the factors that control their relaxation to triplet state species. The research has several broad impacts. Students are trained in classical organic chemistry as well as ultrafast spectroscopic techniques and advanced computational methods. Students will learn to work in a group that does synthetic chemistry, analytical chemistry, ultrafast spectroscopy and theory. Organic, analytical and physical chemists work together and learn from each other. Historically, the Platz Laboratory welcomes women, minority and majority high school student interns, undergraduates, graduate students, post doctoral students and visiting faculty. Students learn to work with individuals of many races, ethnicities, nationalities and educational level. Numerous graduates of the laboratory have been placed in university, college and high school positions teaching chemistry, and they are committed to continue this tradition.