Sudies on Ionic Intermediates by Flash Photolysis

闪速光解法研究离子中间体

• 批准号: 04640498
• 负责人: OKUYAMA Tadashi
• 金额: $ 1.28万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04640498/
• 关键词: Flash photolysis; Laser photolysis; Photoreaction; Radical cation; Carbocation; Electron transfer; Unstable intermediate; 置換基効果

Reactivity of dithiolanylium ions generated by flash photolysisi of 2-methoxy-2-aryl-1,3-dithiolane carrying various ring substituents were examined in aqueous solution. The isolated perchlorate salts of some of these carbocations were also studied for comparison. The substuent effect analyzes according to the Yukawa-Tsuno equation show that the transition state for the hydration of the carbocation is claser to the initial state rather than the product. Photolysis of 2-ethoxy-1,3-dithiolane in the presence of 9-cyanoanthracene (9CA) as an electron acceptor in methanol gave products of ring opening, that may result form the radical cation of the dithiolane.Laser photolysis (YAG, 266 nm) of various 9-alkoxy-9(p-methoxyphenyl)xanthene in aqueous solution whowed formation and decay of the 9-arylxanthenylium ion. The rate of the decay of the cation is dependent on the alkoxyl group, shwing that the decay occurs form the ion pair of the xanthenylium ion and the alkoxide anion.Photolysis of 9-benzylxanfhene in the presence of 9CA resulted in a complex mixture of pfoducts, but its photolysis in aqueous K_2S_2O_8 solution gave xanthone via xanthenol. The laser photolysis of 9-benzylxanthene showed a transient formation of xanthenylium ion. These results show that the raction mechanism involves an electron transfer form the xanthene to SO_<4->・and cleavage to five benxyl radical and xanthenylium ion which is hydrated to xanthenol. The xanthenol formed can rapidly be oxidezed to xanthenone.

研究了2-甲氧基-2-芳基-1，3-二硫戊环在水溶液中闪光光解产生的二硫戊环离子的反应性。这些碳阳离子的一些孤立的高氯酸盐也进行了研究比较。根据Yukawa-Tsuno方程进行的取代效应分析表明，碳正离子水化的过渡态是初始态而不是产物。以9-氰基蒽（9 CA）为电子受体，在甲醇中光解2-乙氧基-1，3-二硫戊环，得到开环产物，这些产物可能是二硫戊环的自由基阳离子的产物.阳离子的衰减速率与烷氧基有关，说明衰减是通过氧杂蒽鎓离子和烷氧基阴离子的离子对进行的，9-苄基氧杂蒽在9 CA存在下的光解产生复杂的产物混合物，而在K_2S_2O_8水溶液中的光解则通过氧杂蒽酚生成氧杂蒽酮。9-苄基氧杂蒽的激光光解过程中，有氧杂蒽鎓离子的瞬时生成。结果表明，反应机理为氧杂蒽与SO_ ·发生电子转移<4->，裂解生成5个苄基自由基和氧杂蒽鎓离子，氧杂蒽鎓离子水合生成氧杂蒽酚。形成的吨烯醇可以迅速氧化为吨酮。

项目成果

奥山 格: "Kinetics and mechanism of 2-aryl-1,3-dithiolan-2-ylium ions in aqueous solution" Bull.Chem.Soc.Jpn.67(発表予定). (1994)

Itaru Okuyama：“水溶液中 2-aryl-1,3-dithiolan-2-ylium 离子的动力学和机理”Bull.Chem.Soc.Jpn.67（待提交）。

奥山 格: "Flash Photolytic Generation of a dithio Carbocation from 1,3-Dithiolane Derivatives" Bulletin of the Chemical Society of Japan. 64. 2751-2756 (1992)

Itaru Okuyama：“从 1,3-二硫杂环戊烷衍生物中快速光解生成二硫代碳阳离子”，日本化学会通报 64. 2751-2756 (1992)。

Tadashi Okuyama, Tonoki Takino, Takuya Sueda, and Masahito Ochiai: "Solvolysis of a cyclohexenyliodonium salt. Remakable nucleofuge and return form intimate ion pair" J.Am chem Soc.(in press).

Tadashi Okuyama、Tonoki Takino、Takuy​​a Sueda 和 Masahito Ochiai：“环己基碘鎓盐的溶剂分解。Remakable 离核并返回形成亲密离子对”J.Am chem Soc.（出版中）。

奥山 格: "Solvolysis of a cyclohexenyliodonium salt:Remarkable nucleofuge and return from intimate ion pair" J.Am.Chem.Soc.116(発表予定). (1994)

Itaru Okuyama：“环己基碘鎓盐的溶剂分解：显着的离核和从亲密离子对返回”J.Am.Chem.Soc.116（待提交）。

Tadashi Okuyama and Hitomi Jinsenji: "kinetics and mechanism of 2-aryl-1,3-dithiolan-2-ylium ions in aqueous slution" Bull. chem. Soc. Jpn.(in press).

Tadashi Okuyama 和 Hitomi Jinsenji：“水溶液中 2-芳基-1,3-二硫杂环戊烷-2-基鎓离子的动力学和机理”公牛。