Study of the Spin Alignment in the Photo-Excited States of Organic High-Spin Molecules and Magnetic Polymers

有机高自旋分子和磁性聚合物光激发态自旋排列的研究

• 批准号: 07454191
• 负责人: TEKI Yoshio
• 金额: $ 4.99万
• 依托单位: Osaka City University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07454191/
• 关键词: organic high-spin molecule; molecular magnetism; spin chemistry; stable radical; spin alignment; photo-excited high-spin state; Zero-field ODMR; optical spectra; 多スピン系有機分子; 光検出磁気共鳴; 蛍燐光スペクトル; 蛍光スペクトル; organic high-spin molecule; molecular magnetism; spin chemistry; stable radical; spin alignment; photo-excited high-spin state; Zero-field ODMR; optical spectra; 多スピン系有機分子; 光検出磁気共鳴; 蛍燐光スペクトル; 蛍光スペクトル

This project has been carried out in order to clarify the electronic states and the spin alignment on the photo-excited states of multi-spin open-shell organic molecules in which the spin correlation among the unpaired spins exists. We have succeeded to construct a high-sensitivity zero-field optically detected magnetic resonance apparatus (ODMR) which is very useful and dispensable to study the excited spin states. We have synthesized several model compounds for the study of their ground and excited spin states. I have investigated the magnetic and optical properties of a series of thioaminyl radical crystals, stable nitronylnitroxide radicals and the spin alignment of the organic high-spin molecules. The tree stable thioaminyls show ferromagnetic behaviors described using the one-dimentional Heisenberg model with the large ferromagnetic interaction of 2J/kbeta = 28.0, 11.4 and 3.6 K.The low-temperature susceptibility and heat capacity measure-ments of the crystal showing 2J/kbeta = 2 … More 8.0 reveals a magnetic phase transition at 0.4 K.For the unique organic high-spin molecule, 4T4'Q-ether, a quantum spin contraction phenomena has been discovered in its triplet ground state with, low-lying quintet and septet excited states. Using the above-mentioned ODMR apparatus and low-temperature optical spectroscopy, We have studied the photo-excited spin states of these compounds. We have succeeded to detect the phosphorescence spectra for biphenyl-3,3'-bisphenylmethylene, naphthalene-nitronylnitroxide radical, and Br-substituted, pyrene-nitronylnitroxide radical. This finding indicates that the existence of the photo-excited high-spin (S<greater than or equal>3/2) states, leading to the determination of the location of the excited high-spin states above the ground states. An ODMR spectrum was observed for Br-substituted pyrene-nitronylnitroxide radical. The detail study of the photo-excited high-spin state is in progress. The problems of the low efficiency of the intersystem-crossing and a strong spin forbidden effect between the excited doublet and excited quartet states were revealed. These findings lead to an important research subject for "the photo-excited spin science and spin chemistry". We also find out a clue to solving the low-efficiency intersystem crossing problem by the heavy atom substitution. The detail study of the titled research subject is now going in progress. This project has lead to a new development in the field of the spin chemistry as well as revealing the problem of the strong spin forbidden between the excited doublet and quarte Less

为了澄清电子状态和在光启用的多旋转开放式有机分子的光启动状态下，该项目进行了，其中不成对旋转之间的自旋相关性。我们成功地构建了高灵敏的零视场光学检测到的磁共振设备（ODMR），该设备非常有用且可用于研究激发自旋状态。我们已经合成了几种模型化合物，用于研究其地面和激发自旋状态。我已经研究了一系列硫氨基自由基晶体，稳定的硝基氧化物自由基和有机高旋转分子的自旋比对的磁性和光学特性。树木稳定的硫氨基氨基示出了使用一维的海森堡模型描述的铁磁行为，其高铁磁相互作用为2J/kbeta = 28.0、11.4和3.6 K.低调的易感性和热能度测量值，显示2J/kbeta = 2…kbeta = 2…更多地显示了一个均值。高自旋分子，4T4'Q-埃克，在其三重态基态以低洼的Quantetet和Septet激发态下发现了量子自旋收缩现象。使用上述ODMR设备和低温光谱学，我们研究了这些化合物的光激发自旋态。我们已经成功地检测了双苯基-3,3'-三苯基甲基烯，萘硝基硝基氧化物自由基的磷光光谱，以及BR取代的，吡啶 - 硝基硝基氧化物自由基。这一发现表明，光激发的高旋转（s <大于或等于> 3/2）状态的存在，导致确定激发的高旋转状态在基础状态上方的位置。对于BR取代的吡啶 - 硝基硝基氧化物自由基观察到ODMR光谱。照片激发的高旋转状态的详细研究正在进行中。揭示了激发双线和激发四重奏状态之间的低效率和强旋转效应的低效率的问题。这些发现导致了“光激发旋转科学和自旋化学”的重要研究主题。我们还发现了通过重原子替代解决低效率的跨系统交叉问题的线索。标题为“研究主题”的详细研究正在进行中。该项目已导致自旋化学领域的新发展，并揭示了激发双线和Quarte之间禁止强烈自旋的问题。