Ground and Excited State Chemistry of Diazirines and Carbenes

9314894 Platz通过光化学方法生成卡宾， 将研究这些瞬态中间体的反应。 将进行实验，以提供基本的 关于几何结构、单重态/三重态能量的信息 水平，热的形成，和利率的内部和 卡宾的分子间反应强调将 基于对烷基卡宾重排的理解， 当低激活熵和大负熵 的激活被观察到。特别是 隧道的可能性作为解释不寻常的 激活参数将被追踪。的化学性质 将详细研究激发态二氮杂环丙烷，因为 这些碳烯的前体可能模拟了 卡宾。沿反作用表面的沿着几个点将 以激发态反应为特征 二氮杂环丙烷。 %有机动力学计划的这一赠款支持 Matthew S教授的持续工作。俄亥俄州普拉茨 大学卡宾是高能化合物， 只有两个键从碳到其他元素，而稳定 碳的化合物含有四个与其他元素相连的键。在 大量的反应，卡宾中间体， 生成的.这些转瞬即逝的中间体的寿命 将被确定为结构的函数， 卡宾、溶剂极性和温度。这些研究 将使我们对这些重要的 中间体及其在合成中的用途。 ***

9314894 Platz The generation of carbenes by photochemical methods and reactions of these transient intermediates will be studied. Experiments will be carried out to provide fundamental information about the geometry, singlet/triplet energy levels, heats of formation, and rates of intra-and intermolecular reactions of carbenes. An emphasis will placed on understanding the rearrangement of alkyl carbenes, where low activation enthalpies and large negative entropies of activation have been observed. In particular, the possibility of tunneling as an explanation for the unusual activation parameters will be pursued. The chemistry of excited state diazirines will be studied in detail, since these precursors to carbenes may mimic some of the chemistry of carbenes. Several points along the reaction surface will be characterized for the reaction of excited state diazirines. %%% This grant from the Organic Dynamics Program supports the continuing work of Professor Matthew S. Platz at Ohio State University. Carbenes are high energy compounds which contain only two bonds to other elements from carbon, while stable compounds of carbon contain four bonds to other elements. In a large number of reactions, carbene intermediates are generated. The lifetimes of these fleeting intermediates will be determined as a function of structure of the carbene, solvent polarity, and temperature. These studies will lead to a basic understanding of these important intermediates and to their use in synthesis. ***