Study on the Electronic Structure of the Excited States and its Reaction of Triple Bond Conjugated Molecules

三键共轭分子激发态电子结构及其反应的研究

• 批准号: 11440210
• 负责人: TERO Shozo
• 金额: $ 5.7万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 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/en/grant/KAKENHI-PROJECT-11440210/
• 关键词: Triple-bond conjugated molecules; Diphenylpolyynes; Triplet states; Zero-field splitting constants; Spin-orbit interaction; 励起一重項状態; 三重結合共役; 時間分解EPR; リン光スペクトル; けい光スペクトル; 三重結合共役分子(ポリイン); フーリエ変換EPR測定; 電子スピン密度; ジフェニルポリイン

The following are the main results obtained in the present study.(1) Diphenylpolyynes (DPY) have a linear planar structure belonging to the D_<2h> point group in the T_1 states, which were assigned to ^3B_<1u> (π_xπ_x^*) in character.(2) The T_1 (π_xπ_x^*) states of DPY have unusually large negative D values for the ZFS parameters that increase with increasing the molecular size.(3) The large negative D value was interpreted in terms of the spin-orbit interaction between the T_1(^3π_xπ_x^*) state and the upper-lying ^3Au (π_xπ_y^*) state.(4) The energy gap between these two states was determined from the observed D values and the calculation of the spin-orbit matrix, indicating that the value decreases with increasing the number of triple bonds.(5) The rapid radiationless transition was also found in the decay from the T_1 state to the S_0 state. The k_<nr> value increases with the decrease in the energy separation between the T_1 and S_0 states, indicating the importance of the Franck-Condon factor between them for the nonradiative deactivation.(6) The appearance of the satellites due to the b_<1g> vibronic bands in the phosphorescence spectra of DPY suggests that the potential surface in the T_1 states would be shallow along the b_<1g> coordinate by the vibronic coupling between the T_1 (π_xπ_x^*) and the ^3π_xπ_y states promoted by the ring twisting motion.(7) Therefore, it is concluded that the energy proximity between the T_1 (^3B_<1u>:π_xπ_y^*) and Tu(^3Au:π_xπ_y^*) states in DPY not only increases the negative D values of the ZFS parameters by the spin-orbit interaction but also accelerates the nonradiative decay from the T_1 state by the vibronic interaction.

本研究取得的主要结果如下：（1）二苯基多炔（DPY）在T_1态下具有属于D_<2h>点群的线性平面结构，被分配给^3B_<1u>（π_xπ_x^ *) 特征。(2) DPY 的 T_1 (π_xπ_x^*) 状态对于 ZFS 参数具有异常大的负 D 值，该值随着分子的增加而增加(3) 大的负 D 值是根据 T_1(^3π_xπ_x^*) 态和上层 ^3Au (π_xπ_y^*) 态之间的自旋轨道相互作用来解释的。(4) 能隙从观测到的D值和自旋轨道矩阵的计算确定了这两种状态之间的值，表明该值随着三键数量的增加而减小。（5）在衰变中也发现了快速无辐射跃迁k_<nr>值随着T_1和S_0态之间能量分离的减小而增大，表明它们之间的Franck-Condon因子对于非辐射失活的重要性。(6)由于 DPY 磷光光谱中的 b_<1g> 电子振动带，卫星的变化表明 T_1 态中的势表面沿着 b_<1g> 坐标会很浅环扭转运动促进的 T_1 (π_xπ_x^*) 和 ^3π_xπ_y 态之间的振动耦合。(7) 因此，可以得出 T_1 (^3B_<1u>:π_xπ_y^*) 和 ^3π_xπ_y^* 之间的能量接近度DPY 中的 Tu(^3Au:π_xπ_y^*) 状态不仅通过自旋轨道相互作用增加了 ZFS 参数的负 D 值，而且还通过电子振动相互作用加速 T_1 态的非辐射衰变。

项目成果

Y.Nagano, T.Ikoma, K.Akiyama, S.Tero-Kubota: "Electronic and Molecular Structure of α,ω-Diphenylpolyynes in the Lowest Excited Triplet States"Chem. Phys. Lett.. 303. 201-208 (1999)

Y.Nagano、T.Ikoma、K.Akiyama、S.Tero-Kubota：“最低激发三重态下 α,ω-二苯基多炔的电子和分子结构”Chem. Phys. 303. 201-208 (1999) ）

H.Oshio, M.Yamamoto, T.Ito, N.Koga, T.Ikoma, S.Tero-Kubota: "Experimental and Theoretical Studies on Ferromagnetically Coupled Metal Complexes with Imino Nitroxides"Inorg. Chem.. 40(22). 5518-5525 (2001)

H.Oshio、M.Yamamoto、T.Ito、N.Koga、T.Ikoma、S.Tero-Kubota：“亚氨基氮氧化物铁磁耦合金属配合物的实验和理论研究”Inorg。

手老 省三, 真嶋 哲朗: "フリーラジカル"米田出版. 196 (1999)

Shozo Tero、Tetsuro Mashima：“自由基”米田出版 196（1999）。

H. Oshio, M. Yamamoto, T. Ito, H. Kawauchi, N. Koga, T. Ikoma, and S. Tero-Kubota: "Experimental and Theoretical Studies on Ferromagnetically Coupled Metal Complexes with Imino Nitroxides"Inorg. Chem.. 40(22). 5518-5525 (2001)

H. Oshio、M. Yamamoto、T. Ito、H. Kawauchi、N. Koga、T. Ikoma 和 S. Tero-Kubota：“亚氨基氮氧化物铁磁耦合金属配合物的实验和理论研究”Inorg。

S.Tero-Kubota: "Singlet and Triplet Energy Splitting in Radical Ion Pairs Generated by Photoinduced Electron Transfer Reactions"Pure & Applied Chem.. (印刷中). (2001)

S.Tero-Kubota：“光诱导电子转移反应产生的自由基离子对中的单线态和三线态能量分裂”Pure & Applied Chem..（印刷中）。