钴-类Fenton体系导致卤代醌类化合物产生独特化学发光的分子机制及应用研究

Halogenated quinoid compounds are considered as the primary metabolites and degradation products of the ubiquitous halogenated aromatic persistent organic pollutants (POPs), which has also been unambiguously detected and identified in drinking water recently. Our previous research showed that the reaction between tetrachloro-1,4-benzoquinone (TCBQ) and H2O2 could generate an unique •OH-dependent intrinsic chemiluminescence (CL), while no CL emission could be observed from H2O2 and 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (DDBQ), the hydroxylation product for TCBQ. Recently we found, however, that a distinct CL could be generated from DDBQ by Co(II)-mediated Fenton-like system. Further investigations indicated that the production of different types of reactive oxygen species (ROS) might be critical for this Co(II)-mediated distinct CL emission. Therefore, in this study, we plan to investigate the specific role of ROS; the change of valence and coordination mode of Co(II); the structure-activity relationship between halogenated quinoids structures and CL emission; test whether other redox-active transition metal-mediated Fenton-like system could also induce similar CL emission; and propose the exact molecular mechanism for this distinct CL emission. Furthermore, on the basis of these results, we expect to develop a highly sensitive CL-producing system to not only detect and quantify halogenated aromatics, but also to monitor their real-time degradation kinetics. These findings may provide technical support for the degradation and remediation of these ubiquitous and toxic halogenated aromatic POPs, which have broad environmental implications for future research on these types of important pollutants.

卤代醌类化合物是环境中无处不在的卤代芳烃类有机污染物的主要降解代谢物，近期在饮用水中也被检出。先前的研究表明，四氯苯醌与H2O2反应会产生依赖于羟基自由基的化学发光，但其羟基化产物2,5-二氯-3,6-羟基-1,4-苯醌（DDBQ）与H2O2却不会产生化学发光。然而我们最近发现Co(II)介导的类Fenton体系能导致DDBQ产生独特的化学发光。进一步研究表明该体系会产生多类活性氧物种(ROS)，这可能是其产生独特化学发光的关键原因。本课题拟深入探讨不同ROS、Co(II)的价态及配位方式变化对化学发光的具体作用；卤代醌结构与化学发光的构效关系；考察其它金属离子介导的类Fenton体系是否也能导致化学发光；阐明产生化学发光的确切分子机制。拟进一步开发出一种更灵敏的化学发光体系用于定量检测卤代芳烃及监测其降解动力学，这将为卤代芳烃类有机污染物的降解与污染修复提供指导技术，具有重要的环境意义。

我们之前的研究发现，致癌性四氯-1,4-苯醌（TCBQ）和H2O2反应会产生非同寻常的两步依赖于羟基（•OH）的化学发光。然而，四氯苯醌发生两次化学发光反应后的终产物氯冉酸（DDBQ）则不会与H2O2反应产生•OH以及化学发光。在本研究中，我们意外发现，多种过渡金属离子介导的类Fenton体系均可介导CA产生独特的化学发光，其中Co(II)介导产生的化学发光最强。有趣的是，我们发现化学发光、CA降解以及活性氧（ROS）的产生随Co(II)：CA摩尔比例改变而显著变化。与经典的Fe(II)-Fenton体系相比，我们发现Co(II)-类Fenton体系导致的化学发光更强、CA降解更高效，而这些都依赖于在特定位点产生了高反应活性的•OH，而不是体系产生的其它ROS产物如O2•-和1O2。值得注意的是，不仅CA，其他卤素取代的卤冉酸以及卤代邻苯二酚也可以经Co(II)-类Fenton体系诱导产生明显的化学发光。本项目研究首次发现了Co(II)-类Fenton体系介导的卤代羟基醌类的高级氧化降解过程中会产生独特的化学发光，而其产生则依赖于特定位点产生的•OH。上述研究结果在检测和定量卤代羟基醌类，以及开发更高效的高级氧化技术用于降解上述类型的重要环境污染物方面具有潜在的应用价值。