Spin Alignment of π-Conjugated Spin Systems Using the Dynamics

在这个项目中，我们得到了以下两个有代表性的结果。(1)首次获得了通过离子对态（电荷分离态）产生独特动态电子极化（DEP）的光激发四重奏态的证据。离子对状态是由分子内光诱导电子从蒽基团转移到体功能组分而产生的。这种独特的DEP模式只在光系统I、II和模型化合物的三重态中被报道过。这是首次在四重奏高自旋态中检测到独特的DEP模式。(2)我们还成功地探测到由四个未成对电子产生的一种新的最低光激发三重态（S=1）。低洼五态（S=2）光激发态位于光激发态之上。通过激发态自旋耦合器在两个自由基自旋之间进行反铁磁自旋排列，降低了独特的三重态的D值。给出了自旋取向和减少自由基-三重自由基体系精细结构分裂的一般理论预测。除上述结果外，我们还研究了几种电子给体部分为π自由基且具有光激发四重奏高自旋态的电荷转移配合物。我们还用光激发的高自旋有机分子作为配体，澄清了一些金属配合物的磁性能。此外，我们利用脉冲ESR技术结合脉冲激光激发，研究了π自由基光激发高自旋态的自旋动力学。

In this project, we have obtained the following two representative results.(1)We have obtained the first evidence of the photo-excited quartet state with a unique dynamic electron polarization (DEP) generated through the ion-pair state (charge separated state). The ion-pair state is generated by the intramolecular photo-induced electron transfer from the anthracene moiety to the bodipy functional component. Such a unique DEP pattern has been reported only for the triplet states of the photosystems I, II and the model compounds. This is the first detection of the unique DEP pattern detected in the quartet high-spin state.(2)We have also succeeded to detect a novel lowest photo-excited triplet (S=1) state arising from four unpaired electrons. The low-lying quintet (S=2) photo-excited state was located above the photo-excited triplet state. The unique triplet state has D value reduced by the antiferromagnetic spin alignment between two radical spins through the excited triplet spin coupler. The general theoretical predictions of the spin alignment and the reduction of the fine-structure splitting of the radical-triplet-radical system are presented.In addition to the above results, we investigated several charge-transfer complexes, in which the electron donor parts are the π-radicals with the photo-excited quartet high-spin states. We also clarified the magnetic properties of the some metal complexes using the photo-excited high-spin organic molecules as ligands. Furthermore, we studied the spin dynamics of the photo-excited high-spin states of the π-radicals using a pulsed ESR technique combined with a pulsed LASER excitation.