An EPR characterisation of stable and transient reactive oxygen species formed under radiative and non-radiative conditions
An EPR characterisation of stable and transient reactive oxygen species formed under radiative and non-radiative conditions
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DOI：
10.1007/s11164-019-04001-0
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发表时间：
2019-10-21
影响因子：
3.3
通讯作者：
Che, M.
中科院分区：
文献类型：
--
作者：
Richards, E.;Murphy, D. M.;Che, M.
电子顺磁共振（EPR）光谱是检测和研究各种顺磁氧中心自由基的理想方法。对于简单的双原子自由基，例如超氧化物（O-2（-））或过氧（ROO中心点）物质，这些物质的CW EPR曲线（特别是g值）可能看起来相似，在某些情况下确实无法区分。因此，使用O-17富集氧的实验揭示了丰富的O-17超精细模式，对于区分这两种物种至关重要。然而，在许多情况下，特别是涉及TiO 2的情况下，过氧型（ROO中心点）自由基或其他中间物种，如[O-2（-）.有机]-型加合物在性质上可以是瞬时的，并且可以再次产生类似的G值。一般而言，这些活性氧物质（ROS）在低温条件下形成和检测。因此，EPR光谱在表面稳定的氧中心自由基研究中的应用必须在精心选择的条件下进行，以确信区分不同类型的双原子自由基，如O-2（-），ROO中心点或[O-2（-）.有机的]。
Electron paramagnetic resonance (EPR) spectroscopy is the ideal method of choice when detecting and studying the wide variety of paramagnetic oxygen-centred radicals. For simple diatomic radicals, such as the superoxide (O-2(-)) or peroxy (ROO center dot) species, the CW EPR profile (in particular the g-values) of these species can appear similar and indeed indistinguishable in some cases. Experiments using O-17-enriched oxygen, revealing a rich O-17 hyperfine pattern, are therefore essential to distinguish between the two species. However, in many cases, particularly involving TiO2 photocatalysis, the peroxy-type (ROO center dot) radicals or other intermediate species such as the [O-2(-) ... organic]-type adducts can be transient in nature and once again can produce similar g-values. In general terms, these reactive oxygen species (ROS) are formed and detected at low-temperature conditions. Hence, the application of EPR spectroscopy to studies of surface-stabilised oxygen-centred radicals must be performed under carefully selected conditions in order to confidently distinguish between the differing types of diatomic radicals, such as O-2(-), ROO center dot or [O-2(-) ... organic].