Suga Kyou, Ohkubo Kei, Fukuzumi Shunichi
Department of Material and Life Science, Graduate School of Engineering, Osaka University, SORST, Japan Science and Technology Agency (JST), Suita, Osaka, 565-0871, Japan.
J Phys Chem A. 2006 Mar 23;110(11):3860-7. doi: 10.1021/jp056637s.
Photoirradiation of the absorption band of the 10-methylacridinium ion (AcrH+) with visible light in deaerated CH3CN/H2O (1:1 v/v) containing pivalic acid (Bu(t)COOH) and less than 1 equiv of NaOH results in the selective formation of 9-tert-butyl-9,10-dihydro-10-methylacridine (AcrHBu(t)). The same product is obtained in O2-saturated CH3CN/H2O under visible light irradiation. Photoirradiation of the absorption band of AcrHBu(t) with UV light in deaerated CH3CN/H2O (1:1 v/v) results in the formation of tert-butyl hydroperoxide (Bu(t)OOH), accompanied by regeneration of AcrH+. This cycle can be repeated several times. When AcrH+ is replaced by the 9-phenyl derivative (AcrPh+), AcrPh+ acts as an effective photocatalyst for the one-pot photooxygenation of Bu(t)COOH in the presence of less than 1 equiv of NaOH relative to Bu(t)COOH with O2 to yield Bu(t)OOH and Bu(t)H. The photocatalytic oxygenation mechanism is discussed based on the detection of radical intermediates by laser flash photolysis and ESR measurements as well as quantum yield determination.
在含有新戊酸（叔丁基羧酸，Bu(t)COOH）且氢氧化钠用量小于1当量的脱氧乙腈/水（1:1 v/v）混合溶液中，用可见光照射10 - 甲基吖啶离子（AcrH⁺）的吸收带，会选择性地生成9 - 叔丁基 - 9,10 - 二氢 - 10 - 甲基吖啶（AcrHBu(t)）。在可见光照射下，在氧气饱和的乙腈/水混合溶液中也能得到相同的产物。在脱氧乙腈/水（1:1 v/v）中用紫外光照射AcrHBu(t)的吸收带，会生成叔丁基过氧化氢（Bu(t)OOH），同时伴随着AcrH⁺的再生。这个循环可以重复多次。当用9 - 苯基衍生物（AcrPh⁺）代替AcrH⁺时，相对于叔丁基羧酸（Bu(t)COOH），在氢氧化钠用量小于1当量且存在氧气的情况下，AcrPh⁺可作为一种有效的光催化剂，用于将叔丁基羧酸（Bu(t)COOH）一锅法光氧化，生成叔丁基过氧化氢（Bu(t)OOH）和叔丁基氢（Bu(t)H）。基于激光闪光光解和电子自旋共振测量对自由基中间体的检测以及量子产率的测定，对光催化氧化机理进行了讨论。
