Photo-Induced Spin Alignment Using Photo-Excited High-Spin State of π-Conjugated Stable Radicals

本项目的目的是为了阐明π共轭有机多自旋体系的电子结构和光激发态自旋取向的主导机制。通过该项目获得了以下新的发现。（1）根据上述方案，我们研制了瞬态吸收光谱仪和时间分辨荧光测量系统，并配以变温系统。光激发的高自旋有机体系的寿命约为100。在77K下，该装置的测量时间为10 - 20 μ s。（2）首次发现了Verdazyl自由基体系的光激发四重态和五重态高自旋态。芘-verdazyl自由基的光激发四重态高自旋态也被检测到。在此基础上，详细阐明了获得光激发高自旋态的必要条件，为有机自旋聚合物的分子设计奠定了指导性原则 ...更多信息 n系统的高自旋光激发态。（3）通过研究蒽-叔丁基氮氧自由基的光激发态，证明了π拓扑在光激发态自旋排列中的作用。(4)A通过考虑π拓扑结构的适当分子设计，首次发现了由四个未成对电子构成的独特的最低三重态光激发态。反铁磁分子内自旋取向降低了精细结构参数的大小。（5）合成了具有光激发高自旋态的稳定自由基，并通过引入二甲氨基改善了其给电子性质，研究了它们的电子态和物理性质。解决了其中一个问题，即利用具有光激发高自旋态的π共轭有机自旋体系构建电荷转移复合物。(6)In为了探索利用有机自旋体系进行LIESST的可能性，我们合成了几种由π共轭有机自旋体系与光激发高自旋态和合适的电子受体构成的电荷转移配合物。通过ESR、时间分辨ESR、光吸收和SQUID测量，阐明了它们的基本物理和光学性质以及电子结构。少

This project was carried out in order to clarify the electronic structure and the dominant mechanism of the spin alignment in the photo-excited states of π-conjugated organic multi-spin systems. The following new findings were obtained through this project.(1)According to the proposal, we make up the transient absorption spectroscopy apparatus as well as the time-resolved fluorescence measurement system attached with variable temperature system. The life-times of the photo-excited high-spin organic systems were determined to be ca. 10-20 μs at 77 K using this apparatus.(2)The photo-excited quartet and quintet high-spin states of the verdazyl radical systems have been first detected. The photo-excited quartet high-spin state was also detected for the pyrene-verdazyl radical. Based on these results, the necessary conditions to obtain the photo-excited high-spin state have been clarified in detail and succeeded to establish the guiding principles for the molecular designing of organic spi … More n system with the high-spin photo-excited state.(3)The role of π-topology in the spin alignment on the photo-excited state has been proven by studying the photo-excited states of π-conjugated Anthracene-t-Butyl-Nitroxide radicals.(4)A unique lowest triplet photo-excited state constructed from four unpaired electrons was detected for the first time by the proper molecular design taking π-topology into account. The magnitude of the fine-structure parameters is reduced by the antiferromagnetic intramolecular spin alignment.(5)The stable radicals with photo-excited high-spin states, which electron donor property was improved by attaching dimethylamino group were synthesized and their electronic states and physical properties were investigated. One of the problems was solved, which are concerned with the construction of the charge-transfer complexes using the π-conjugated organic spin systems with the photo-excited high-spin states.(6)In order to investigate the possibility of LIESST using organic spin systems, we synthesized several charge-transfer complexes constructed from the π-conjugated organic spin systems with the photo-excited high-spin states and the proper electron accepters. Their basic physical and optical properties as well as the electronic structures were clarified by ESR, time-resolved ESR, optical absorption, and SQUID measurements. Less