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Instrumental Development in Time Resolved Infrared Spectroscopy with Microsecond Time Resolution

微秒时间分辨率的时间分辨红外光谱仪器的发展

基本信息

批准号：
04554019
负责人：
TOMIOKA Hideo
金额：
$ 5.25万
依托单位：
MIE UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

This research was undertaken to develope a time-resolved infrared spectroscopy (TRIR) with microsecond time resolution for studying transient products involved in photolysis of organic molecules by collaborate efforts of physical organic chemists expert in reactive intermediate and technical experts in spectroscope instrumentation.In order to evaluate and modify the equipment promptly and properly, precursor compounds suitable for such study were carefully chosen by using matrix-isolation spectroscopy (MIS) which provided spectroscopic features of transient species and time-resolved UV-vis spectroscopy (TRUV) which afforded decay kinetics. Thus, a series of diaryldiazomethanes and arylazides were irradiated and the reactions were monitored by MIS where spectra of the transient photoproducts were recorded and structures were deterined and by TRUV where the kinetic data of these intermediates were measured.TRIR set-up consisted of Xe flash lamp, excimer and YAG lasers as excitation light source so that a variety of precursor molecules can be photoexcited, and xenon IR monitor light. The monitor light was passed through a sample cell and analyzed by using conventional IR spectrometer and detector. Decay curves of transient IR spectra were then integrated and analyzed by computer system.Flash photolysis of the diazomethanes with TRIR was not very fruitful partly due to overlapping absorption of the precursor molecules as well as solvents with those of the transient carbene. However, similar flash photolysis of arylazides in n-heptane provided a transient absorption due to dehydroazepines obviously produced as a result of ring-expansion of the arylnitrenes and the lifetimes of the azepines were successfully determined.

本研究旨在通过反应中间体物理有机化学家和光谱仪器技术专家的共同努力，开发一种具有微秒时间分辨率的时间分辨红外光谱(TRIR)，用于研究有机分子光解的瞬时产物。为了及时和适当地评估和改进设备，利用提供瞬时物种光谱特征的矩阵隔离光谱(MIS)和提供衰减动力学的时间分辨UV-Vis光谱(TRIV)，仔细选择了适合于这类研究的前体化合物。因此，我们对一系列二芳基重氮甲烷和芳氮化物进行了辐照，并用记录瞬时光产物光谱并确定其结构的化学光谱仪和测量了这些中间体的动力学数据的TRUV来监测这些反应。监测光通过样品池，用常规红外光谱仪和检测器进行分析。结果表明，由于前驱体分子和溶剂的吸收与暂态卡宾的吸收重叠，重氮甲烷在TRIR中的闪光光解不是很有效。然而，芳氮化物在正庚烷中的类似闪光光解提供了瞬时吸收，这是由于芳基硝烷的扩环产生了明显的脱氢氮杂环类化合物，并成功地测定了这些氮杂环类化合物的寿命。