Photocatalytic oxygenation of anthracenes and olefins with dioxygen via selective radical coupling using 9-mesityl-10-methylacridinium ion as an effective electron-transfer photocatalyst
Photocatalytic oxygenation of anthracenes and olefins with dioxygen via selective radical coupling using 9-mesityl-10-methylacridinium ion as an effective electron-transfer photocatalyst
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DOI：
10.1021/ja048353b
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发表时间：
2004-12-15
影响因子：
15
通讯作者：
Fukuzumi, S
中科院分区：
文献类型：
--
作者：
Kotani, H;Ohkubo, K;Fukuzumi, S
在含有9，10-二甲基菲的O-2饱和乙腈(MeCN)溶液中，9-甲苯基-10-甲基吖啶离子(ACR(+)-MES)的吸收带在可见光照射下生成氧化产物，即二甲基亚甲基二氧基菲(Me(2)An-O-2)。在光照射下，菲和9-甲基菲也被ACR(+)-MES光催化氧化生成相应的环氧基菲。在菲的情况下，进一步的光照射导致形成最终的六电子氧化产物，通过10-羟基蒽酮，伴随着过氧化氢的生成。当用烯烃(四苯基乙烯和四亚甲基乙烯)取代菲时，烯烃的光催化氧化生成相应的二氧杂环己烷，其中O-O键被裂解成相应的酮。在光催化氧化过程中，由ACR+-MES的光激发引发，形成电子转移态：ACR(.-)MES(.+)，然后电子转移到MES(.+)部分，电子从ACR(.)氧分压的一部分。生成的菲和烯烃自由基阳离子分别与O-2(.-)发生自由基偶联反应，生成环氧基菲(An-O-2)和二氧杂环己烷。
Visible light irradiation of the absorption band of 9-mesityl-10-methylacridinium ion (Acr(+)-Mes) in an O-2-saturated acetonitrile (MeCN) solution containing 9,10-dimethylanthracene results in formation of oxygenation product, i.e., dimethylepidioxyanthracene (Me(2)An-O-2). Anthracene and 9-methylanthracene also undergo photocatalytic oxygenation with Acr(+)-Mes to afford the corresponding epidioxyanthracenes under the photoirradiation. In the case of anthracene, the further photoirradiation results in formation of anthraquinone as the final six-electron oxidation product, via 10-hydroxyanthrone, accompanied by generation of H2O2. When anthracene is replaced by olefins (tetraphenylethylene and tetra methylethylene), the photocatalytic oxygenation of olefins affords the corresponding dioxetane, in which the O-O bond is cleaved to yield the corresponding ketones. The photocatalytic oxygenation of anthracenes and olefins is initiated by photoexcitation of Acr+-Mes, which results in formation of the electron-transfer state: Acr(.-)Mes(.+), followed by electron transfer from anthracenes and olefins to the Mes(.+) moiety together with electron transfer from the Acr(.) moiety to O-2. The resulting anthracene and olefin radical cations undergo the radical coupling reactions with O-2(.-) to produce the epidioxyanthracene (An-O-2) and dioxetane, respectively.