Chemical and Spectroscopic Investigation of Nitrenium Ions

这项研究将涉及光谱和动力学 芳基氮鎓离子产生的评价。虽然 该项目的第一阶段将涉及光解 邻氨基苯甲酸盐，预计几个新的 光化学方法一般生产 芳基氮离子将最终出现。这项研究将 中心采用纳秒级激光闪光光解，低 温度ESR光谱和分子轨道 计算，以提供明确的识别 芳基氮鎓离子。这项工作的一个亮点将是定义 所产生的氮鎓离子的自旋多重性和 从每个自旋状态形成的产物。的问题 单重态-三重态平衡的存在将得到回答， 对最终产品分销的影响将是 划定的芳基氮鎓离子在DNA损伤中的作用 反应也将通过捕获 芳基氮离子与鸟嘌呤模拟致癌 反应性 %%% 这项来自有机动力学计划的新赠款支持 丹尼尔A.法尔维在牛津大学 马里兰州。调查将试图分析反应性 一种叫做氮离子的短寿命分子。 氮离子，其具有带正电荷的氮 收费，受到很少的关注，但代表了一个 具有广泛用途的潜在活性物质类别， 光引起的化学过程。通过使用一种仪器 设计用来拍摄紫外线吸收的“照片”， 短暂的化学物种，生活在几十亿分之一的 第二，它将有可能证实存在的 芳基氮鎓离子， 参与芳胺的DNA损伤过程的实体。

This investigation will deal with spectroscopic and kinetic evaluation of the generation of arylnitrenium ions. Although the initial phase of the project will involve the photolysis of anthranilium salts, it is expected that several new photochemical methods for the general production of arylnitrenium ions will eventually emerge. The study will center on the use of nanosecond laser flash photolysis, low temperature ESR spectroscopy, and molecular orbital calculations to provide unequivocal identification of arylnitrenium ions. A highlight of the work will be to define the spin-multiplicity of the nitrenium ions generated and the products formed from each spin state. The question of the existence of a singlet-triplet equilibrium will be answered and the consequences for final product distribution will be delineated. The role of arylnitrenium ions in DNA damaging reactions will also be investigated by trapping of arylnitrenium ions with guanine to simulate carcinogenetic reactivity. %%% This new grant from the Organic Dynamics Program supports the work of Professor Daniel A. Falvey at the University of Maryland. The investigation will seek to analyze the reactivity of very short lived molecules called nitrenium ions. Nitrenium ions, which possess a nitrogen with a positive charge, have received little attention and yet represent a potential class of reactive species with widespread utility in chemical processes induced by light. By using an instrument designed to take snap-shot ultraviolet absorption "pictures" of transient chemical species which live a few billionths of a second, it will be possible to confirm the existence of arylnitrenium ions which have been implicated as the primary entities involved in the DNA damaging process of arylamines.