作者:Justus von Sonntag、Eino Mvula、Knut Hildenbrand、Clemens von Sonntag
DOI:10.1002/chem.200305136
日期:2004.1.23
phosphate buffer, Q* reacts with H(2)PO(4) (-) giving rise to an adduct which is subsequently oxidized by Q to 2-phosphato-1,4-benzoquinone QP. The current view that (.)OH is an intermediate in the photohydroxylation of Q has been overturned. This view had been based on the observation of the (.)OH adduct of DMPO when Q is photolyzed in the presence of this spin trap. It is now shown that Q*/Q(2)* oxidizes
在水中1,4-苯醌的光解过程中,Q产生等量的2-羟基-1,4-苯醌HOQ和对苯二酚QH(2),其量子产率为Phi = 0.42,与pH和pH无关。 Q浓度。相比之下,作为这些产物前体的三重态(lambda(max)= 282和大约410 nm)的衰减速率非线性地增加(k =(2-> 3.8)x 10(6)s(-1) ))随着Q浓度的增加((0.2-> 10)mM)。在三重态衰减后,通过激光闪光光解检测的自由基产率也随着Q浓度的增加而增加,但遵循不同的功能形式。这些观察结果可以通过单体三重态Q *和激基复合物Q(2)*(K = 5500 +/- 1000 M(-1))的快速平衡来解释。虽然Q *加水,随后烯醇化为1,2,4-三羟基苯Ph(OH)(3),Q(2)*通过电子转移和加水而衰减,从而生成苯并半醌(。)QH和(。)OH加合物自由基(。)QOH。后者在三重态衰变的时间尺度内烯醇化为2-羟基-1