Investigation of Hydrated Electron Quenching by Quinone Compounds under Micellar Reaction Environment

我们研究了在加入正丙醇的十二烷基硫酸钠和SOS胶束溶液中，艾地苯酮(IDB)及其相关化合物(CoQ0)对水合电子(e&lt；aq&gt；^-)的猝灭。在紫外光照射下，IDB与1-PROH中的长侧链反应生成中性自由基，而在电子给体(DABCO)存在的情况下生成阴离子自由基。在胶束溶液中，两种化合物都产生阴离子自由基，但IDB自由基的电子顺磁共振(EPR)强度很弱，当1-PROH加入胶束溶液时，IDB自由基的信号强度增加了近7倍。IDB有效猝灭自由基导致胶束电荷密度降低。因此，上述结果表明，异丁基苯并醌核可定位于…。胶束的更多极地区域。此外，还发现在胶束体系中，异丁二酚以2.1×10~(-6)秒~(-1)~(-1)的准一级动力学猝灭e_&lt；aq&gt；^-。其次，研究了抗氧化剂芝麻酚在水溶液中连续和脉冲紫外光照射产生的中间自由基。在连续紫外光照射下，用连续波电子顺磁共振(CW EPR)观察到了强度比为1：4：6：4：1的自由基物种。为了观察激发后即刻的中间自由基，采用傅立叶变换电子顺磁共振(FT EPR)。用脉冲紫外激光傅立叶变换电子顺磁共振也检测到了同一自由基的痕量。根据超精细偶合常数(2.3G)和g值(2.0048)结合FTEPR结果，确定该自由基为苯醌阴离子自由基。该自由基可能是通过激发芝麻酚在水溶液中的多步反应产生的，并且至少稳定几分钟。FT EPR显示了自由基的详细行为。中间体的表征是评价抗氧化剂芝麻酚的重要依据。较少

We have studied the hydrated electron (e_<aq>^-) quenching by idebenone (IDB) and the related compound (CoQ_0) in SDS and SOS micellar solutions with 1-propanol (1-PrOH) addition. UV irradiation of IDB with the long side chain in 1-PrOH produced the neutral radical, whereas in the presence of an electron donor (DABCO) the anion radical was formed. On the other hand, UV irradiation of CoQ_0 without the side chain produced the anion radical both in the presence and in the absence of DABCO.In micellar solutions, both compounds produced anion radicals but the EPR (electron paramagnetic resonance) intensity of the IDB radical was very weak even in the presence of DABCO.When 1-PrOH was added to the micellar solution, the signal intensity of the IDB radical increased approximately seven-fold. The effective e_<aq>^- quenching by IDB to form the radical results in decrease of micellar charge density. Therefore, the results obtained suggest that the benzoquinone nucleus of IDB can locate in the … More polar region of the micelle. Furthermore, it was found that IDB quenched e_<aq>^- by the pseudo-first-order kinetic with the rate of 2.1x10^6 sec^<-1> in the micelllar system.Next, the intermediate radicals generated by continuous UV and pulsed UV laser irradiation of antioxidant sesamol in aqueous solutions were investigated. Radical species with the intensity ratio of 1 : 4 : 6 : 4 : 1 was observed using continuous wave Electron Paramagnetic Resonance (CW EPR) with continuous UV irradiation. In order to observe the intermediate radical right after the excitation, Fourier Transform EPR (FT EPR) was used. Trace amount of the same radical was also detected by FT EPR with pulsed UV laser. Based on the hyperfine coupling constant (2.3 G) and g-value (2.0048) together with FT EPR results, this radical was found to be a benzoquinone anion radical. The radical might be produced via multi-step reactions of the excited sesamol in aqueous solution and was stable for at least several minutes. FT EPR showed the detailed behavior of the radicals. Characterization of the intermediate is important to evaluate the antioxidant sesamol. Less