Resonance Raman spectroscopic studies of the structure of electrogenerated short-lived radicals in solution by means of column-electrolytic continuous-flow method

建立了一种测量溶液中电生成的短寿命有机自由基的时间分辨共振拉曼光谱的柱电解连续流方法。该方法最大的特点是易于控制物种的浓度，使其成为研究溶液中电生成中间体的有效工具。观察了硫蒽醌自由基的RR谱，并讨论了其在溶液中的结构。基于RR波段的分配。测定了三种芳香胺氧化溶液的红外光谱。光谱不是由阳离子自由基分配的，而是由连续反应中产生的二聚体阳离子自由基分配的。通过控制电解条件，选择488.0 nm和514.0 nm的氩离子激光激发线，对电生成阳离子自由基和二甲二苯联苯胺的还原光谱进行了选择性观察。利用图像增强多通道光电二极管阵列探测器采集了短寿命自由基的时间分辨RR谱。实验证明，在电生成物质的时间分辨测量中，可以实现短于100 ms的时间分辨。利用647.1 nm的氪离子激光，成功地观察了蒽衍生物和联苯胺衍生物阳离子自由基的红外光谱，为拉曼光谱的测量提供了有利条件。

A column-electrolytic continuous-flow method has been developed for the measurement of time-resolved resonance Raman (RR) spectra of electrogenerated short-lived organic radicals in solution. The great feature of this method is t he ease of controlling the concentration of species, which makes the method a powerful tool for the RR study of electrogenerated intermediates in solution.The RR spectrum of the thianthrenecation radical was observed and its structure in the solution was (Liscussed. based on the assignment of the RR bands. The RR spectra of the oxidezed solutions of three aromatic amines were also measured. The spectra were assigned not due to those of cation radicals but to those of dimer cation radicals produced in the consecutive reactions.The selective observation of the RR spectra of electro-generated cation radical and dication of dimethy1diphenylbenzidine were carried out by controlling the electrolysis conditions and selecting the Argon ion laser excitation lines of 488.0 and 514.0 nm. The image-intensified multi-channel photo-diode arrey detector was utilized for the acquisition of time-resolbed RR spectrum of short-lived radicals. It was proved that the time-resolution of shorter than 100 ms could be achieved in the time-resolved measurement of electro-generated species.The RR spectra of the cation radicals of anthracene derivatives and the dications of benzidine derivatives have been successfully observed by using the kripton ion laser exitation of 647.1 nm, which is infavorable conditions for the Raman measurement.