Properties of Isolated and Solvated Aromatic Carbenes

在化学学部物理化学项目中，科罗拉多州立大学的E. Bernstein教授将使用几种激光光谱学方法研究由激光光解和超音速射流冷却产生的冷的、分离的和溶剂化的芳香族二氧化碳分子。这包括在纳秒时间尺度上的荧光激发和分散发射光谱；质量分辨激发光谱；皮秒相关单光子计数；以及各种皮秒时间分辨泵浦/探针光谱。在集群上也将进行类似的工作。互补的从头算和半经验计算将用于协助解释实验数据。卡宾是一种自由基，在许多缩合相化学反应中是重要的中间体。为了理解并最终能够控制这种反应，有必要知道参与的碳物种的性质。从缩合相的研究中直接确定它们的一些关键性质是不切实际的，因此它们大部分是通过动力学测量间接确定的。这项研究直接从气相二氧化碳系统的测量中提供了这些特性。待研究的化合物应提供有关其几何结构、电子结构和反应性之间关系的信息。＊＊＊

9312190 Bernstein In this project of the Physical Chemistry Program in the Chemistry Division, Prof. E. Bernstein of the Colorado State University will study cold, isolated and solvated aromatic carbene molecules created by laser photolysis and supersonic jet cooling using several methods of laser spectroscopy. These include fluorescence excitation and dispersed emission spectroscopies on the nanosecond time scale; mass resolved excitation spectroscopy; picosecond correlated single photon counting; and various picosecond time-resolved pump/probe spectroscopies. Similar work will also be done on clusters. Complementary ab initio and semi-empirical calculations will be used to assist in the interpretation of the experimental data. %%% Carbenes are radicals known to be important intermediates in many condensed-phase chemical reactions. To understand, and ultimately be able to control such reactions, it is necessary to know the properties of the participating carbene species. Direct determination of some of their critical properties from studies of the condensed phase is impractical and they are therefore determined for the most part indirectly from kinetic measurements. This research serves to provide these properties directly from measurements on gas phase carbene systems. The compounds to be investigated should provide information on the relationships between their geometrical structure, electronic structure, and reactivity. ***