Effects of Structural Changes in the Amino group on the Relaxation Processes of Elecronically Excited Aromatic Amines

氨基结构变化对电子激发芳香胺弛豫过程的影响

• 批准号: 11640496
• 负责人: TOBITA Seiji
• 金额: $ 1.92万
• 依托单位: Gunma University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640496/
• 关键词: aromatic amines; internal conversion; fluorescence; radiationless transitions; solvent effects; substituent effects; transient absorption; photoionization; アミノナフタレン; 無輻射過程

Effects of structural changes in the amino group on the relaxation processes of N,N-dimethyl-1- aminonaphthalenes and aniline derivatives were investigated by time-resolved fluorescence, transient absorption and time-resolved photothermal measurements. For N,N-dimethyl-1-aminonaphthalenes it was revealed that structural changes from trwisted to quasi-planar from in the excited state induce vibronic coupling between closely-lying S_1 and S_2 states, resulting in very fast internal conversion in nonpolar solvents. Such a fast nonradiative process was also found for aniline derivatives which have a twisted amino group in the ground state. This work showed that characteristic solvent effects on the relaxation processes of excited aromatic amines could be attributed to structural changes of the amino group in the excited state.The structural change of the amino group from a pyramidal to quasi-planar upon electronic excitation results in intramolecular charge transfer from the nitrogen atom into the ring. As a result photoionization threshold is lowered and one-photon ionization upon 266 or 308nm photon excitation was found to become possible for aniline derivatives in water.

通过时间分辨荧光，瞬时吸收和时间分辨的光热测量，研究了氨基组对N，N-二甲基-1-氨基乙烯和苯胺衍生物的松弛过程的影响。对于N，N-二甲基-1-氨基酰胺乙酰苯二甲甲烯烃揭示了从激发态中从TRWIST到准平面的结构变化会诱导紧密散落的S_1和S_2状态之间的振动耦合，从而导致非极性溶液中非常快速的内部转化率。还发现了在基态呈扭曲氨基的苯胺衍生物中，也发现了这种快速的非生育过程。这项工作表明，对激发芳香胺的松弛过程的特征性溶剂作用可以归因于激发态下氨基群的结构变化。氨基基团在电子激发后从金字塔到到准平面的氨基群的结构变化导致从硝基原生体进入环的片内电荷转移。结果，发现光电离子阈值被降低，并在266或308nm的光子激发上进行单光子电离是水中苯胺衍生物的可能性。

项目成果

M.Moriyama, M.Kosuge, S.Tobita, and H.Shizuka: "Excited-state Intramolecular Proton Transfer Followed by Cis-trans Isomerization of (1-Hydroxy-2-naphthyl)-s-triazine Derivatives"Chem.Phys. 253. 91-103 (2000)

M.Moriyama、M.Kosuge、S.Tobita 和 H.Shizuka：“激发态分子内质子转移随后进行（1-羟基-2-萘基）-s-三嗪衍生物的顺反异构化”Chem.Phys。

S.Tajima,S.Tobita,andH.Shizuka: "Electron Transfer Reastion from Triplet 1,4-Dimethoxybenzene to Hydronium Ion in Aqueous Solution"J.Phys.Chem.. 103. 6097-6105 (1999)

S.Tajima、S.Tobita 和 H.Shizuka：“水溶液中从三重态 1,4-二甲氧基苯到水合氢离子的电子转移反应”J.Phys.Chem.. 103. 6097-6105 (1999)

K.Suzuki,A.Demeter,W.kuhnle,E.tauer,A.Zachariasse,,S.Tobita,andH.Shizuka: "Internal Conversion In 4-Substituted(Dimethylamino)naphthalenes.Influence of the Electron Donor/Acceptor Substituent Charaster"Phys.Chem.Chem.Phys.. 2. 981-993 (2000)

K.Suzuki、A.Demeter、W.kuhnle、E.tauer、A.Zachariasse、S.Tobita 和 H.Shizuka：“4-取代（二甲氨基）萘的内部转换。电子供体/受体取代基特征的影响

S.Tobita,K.Ida,and S.Shiobara: "Water-induced Fluorescence Quenching of Aniline and Its Derivatives in Aqueous Solution"Res.Chem.Intermed.. (in press). (2001)

S.Tobita、K.Ida 和 S.Shiobara：“苯胺及其衍生物在水溶液中的水诱导荧光猝灭”Res.Chem.Intermed..（出版中）。

K.Suzuki, A.Demeter, W.Kuhnle, E.Tauer, K.A.Zachariasse, S.Tobita, and H.Shizuka: "Internal Conversion in 4-Substituted 1-Naphthylamines. Influence of the Electron Donor/Acceptor Substituent Character"Phys.Chem.Chem Phys.. 2. 981-991 (2000)

K.Suzuki、A.Demeter、W.Kuhnle、E.Tauer、K.A.Zachariasse、S.Tobita 和 H.Shizuka：“4-取代 1-萘胺的内部转化。电子供体/受体取代基特征的影响”Phys