TIME-RESOLVED IR SPECTROMETRIC DETECTION SYSTEM FOR KINETIC AND STRUCTURAL STUDIES OF REACTIVE INTERMEDIATES AT AMBIENT TEMPERATURE

本研究的目标是建立一个用于激光闪光光解(LFP)的时间分辨红外探测系统。它的设计紧凑，适合获得高性价比的动力学和结构研究。我们LFP系统的操作软件也进行了修改，以便与红外探测系统同步。到目前为止，可以很容易地检测到具有足够消光系数和数百秒寿命的中间体。另一方面，还利用UV-Vis检测对活性中间体进行了时间分辨光谱研究。我们对这种特殊的卡宾很感兴趣，并试图从前体生成苯环丁烯亚甲基，以研究其反应活性。苯环丁烯酮的N-(2-苯基吡啶)亚胺的LFP(XeCl，308 nm)产生瞬变物种，其最大吸收波长在450 nm左右。在以1μS的寿命消失后，观察到一个寿命较长的物种在510 nm处有弱吸收，其寿命为660μS，根据观察到的对烯烃和醇的反应活性，我们认为前者是由苯环丁烯引起的。后510 nm的瞬变峰可被重氮苯并环丁烯类化合物猝灭，这是因为该物种可被富马腈等亲双极分子猝灭。同一前驱体的LFP与红外检测相似，使我们在2042 cm^~(-1)&g~(-1)处观察到吸收，可归属为重氮苯并环丁烯。其寿命为1ms，与紫外可见光谱的观测结果吻合较好。仪器灵敏度和时间分辨率方面的进一步进展正在进行中，以便能够观察到苯环丁烯亚甲基和吡啶叶立德。

The goal of this study is to build a time-resolved IR detection system for laser flash photolysis (LFP). It is designed to be compact and suited for kinetic and structural studies of gain high cost-performance. The operational software for our LFP system is also modified so that it can be synchronized with the IR detection system. So far, intermediates with sufficient extinction coefficients and the lifetime of some hundred seconds can be readily detected.On the other hand, time-resolved spectroscopic studies of reactive intermediates are also carried out with UV-VIS detection. We are interested in this particular carbene and have attempted to generate benzocyclobutenylidene from precursors in order to investigate its reactivity. LFP (XeCl, 308 nm) of N-(2-phenylazyridyl)imine of benzocyclobutenone results in transient species with its absorption maximum around 450 nm. After these transients disappeared with the lifetime of 1 μs, a longer-lived species was observed as a weak absorption at 510 nm with the lifetime of 660 μs. We assign the former transient as being due to benzocyclobutenylidene based on the observed reactivity toward alkenes and alcohols. The latter 510 nm transient can be assigned as diazobenzocyclobutene because this species can be quenched by dipolarophiles such as fumaronitrile.Similar LFP of the same precursor with IR detection allowed us to observe absorption at 2042 cm^<-1>, which can be assigned as being due to diazobenzocyclobutene. The lifetime is 1 ms, which is in good agreement with the observation by UV-VIS detection. Further progress in the instrumental sensitivity and time-resolution is underway so that benzocyclobutenylidene and the pyridine ylide can be observed.