Doig Adrian I, Tuck Tyler A, LeBlanc Brandon, Back Thomas G
Department of Chemistry, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
ACS Omega. 2022 Jul 28;7(31):27312-27323. doi: 10.1021/acsomega.2c02286. eCollection 2022 Aug 9.
Several 2,7-dialkoxy-substituted naphthalene-1,8-diselenides were prepared and tested for catalytic antioxidant activity in an NMR-based assay employing the reduction of hydrogen peroxide with stoichiometric amounts of benzyl thiol. Acidic conditions enhanced their catalytic activity, whereas basic conditions suppressed it. The highest activity was observed with a 2,7-bis(triethyleneglycol) derivative. These compounds serve as mimetics of the antioxidant selenoenzyme glutathione peroxidase. Studies based on NMR peak-broadening effects and EPR spectroscopy indicated that a thiol-dependent SET reaction occurs under the conditions of the assay, which can be reversed by the addition of triethylamine. In contrast, peak broadening induced by proton-catalyzed electron transfer during the treatment of naphthalene-1,8--diselenides with trifluoroacetic acid can be suppressed by the addition of excess thiol. These observations provide new insights into the redox mechanisms of these processes.
制备了几种2,7-二烷氧基取代的萘-1,8-二硒化物，并在基于核磁共振的分析中测试了它们的催化抗氧化活性，该分析采用化学计量的苄硫醇还原过氧化氢。酸性条件增强了它们的催化活性，而碱性条件则抑制了它。2,7-双（三乙二醇）衍生物的活性最高。这些化合物可作为抗氧化硒酶谷胱甘肽过氧化物酶的模拟物。基于核磁共振峰展宽效应和电子顺磁共振光谱的研究表明，在分析条件下会发生硫醇依赖性单电子转移反应，加入三乙胺可使其逆转。相反，在用三氟乙酸处理萘-1,8-二硒化物过程中，质子催化电子转移引起的峰展宽可通过加入过量硫醇来抑制。这些观察结果为这些过程的氧化还原机制提供了新的见解。
