配合物型自由基间的磁耦合性质研究

发布时间：2018-04-24 07:16

本文选题：配合物 + 自由基　；参考：《山东师范大学》2017年硕士论文

【摘要】：自由基间磁耦合性质的研究是近年来分子基磁学领域的前沿课题之一。鉴于自由基类配合物显示了特殊的双稳态自旋跃迁的性质而使其在分子器件领域具有潜在的广泛应用前景,因此,进行配合物型自由基间的磁耦合机理的研究具有重要的理论与现实应用意义。本论文设计合成了以dmit(1,3-dithiole-1,2-thione-4,5-dithiolate)和mnt(cis-1,2-dicyanothylene-1,2-dithiolate)为配体的四个文献尚未报道的新型自由基配合物,即[N-MePhen-OCH3][Ni(dmit)2]、[Ni(phen)3][Ni(dmit)2]2CH3COCH3、[Ni(2,2’-bpy)3][Ni(mnt)2]2和[Ni(phen)3][Ni(mnt)2]2CH3CN。对这些配合物进行了红外表征、XRD表征、元素分析表征;使用X-射线单晶衍射法分别测定它们在室温和低温时不同温度下的晶体结构;测试了前三个配合物的变温磁化率;根据其晶体结构数据获得了其在不同温度条件下配阴离子间存在的短距离接触相互作用;通过理论计算的方法获得了自由基配阴离子间短距离接触相互作用中的各原子上的电子自旋密度以及其短距离接触原子间的重叠积分;探讨了短距离接触原子上的电子自旋密度及短距离接触原子间的重叠积分与相应的实验磁耦合强度的关联,获得了如下有意义的研究结果:1.首次揭示了:自由基短距离接触原子间的重叠积分绝对值越大其反铁磁耦合强度则越大。2.首次揭示了:自由基间π-π重叠短距离接触原子对上的自旋密度和相关的重叠积分是导致其反铁磁耦合强度的主要两关键因素。3.进一步证实了:短距离接触的一对原子上电子自旋密度同时大于0.1是导致相邻自由基间产生强反铁磁耦合的必要条件之一。本论文的研究结果将对设计合成具有理想的分子基磁性功能器件具有一定的理论和实验指导意义。
[Abstract]:The study of magnetic coupling between free radicals is one of the frontier topics in the field of molecular-based magnetism in recent years. In view of the special bistable spin-transition properties of free radical complexes, which make them have a potential wide application in the field of molecular devices, therefore, The study of magnetic coupling mechanism among complex free radicals has important theoretical and practical significance. In this paper, we have designed and synthesized four novel free radical complexes, [N-MePhen-OCH3] [Ni(dmit)2], [Ni(phen)3] [Ni(dmit)2] 2CH3COCH3, [Ni(mnt)2] 2 and [Ni(phen)3] [Ni(mnt)2] 2CH3COCH3, which are ligands of dmiton 1a 3-dithiole-1n (2-thione-4) and mntntccis-1n (2-dicyanothylene-1n 2-dithiolate), which are not reported in this paper. The complexes are as follows: [N-MePhen-OCH3] [Ni(dmit)2], [Ni(phen)3] [Ni(dmit)2] 2CH3COCH3, [Ni(mnt)2] 2 and [Ni(phen)3] [Ni(mnt)2] 2CH3CN. The complexes were characterized by XRD and elemental analysis. The crystal structures of these complexes at room temperature and low temperature were determined by X-ray single crystal diffraction, and the magnetic susceptibility of the first three complexes at different temperatures were measured. According to the crystal structure data, the short-distance contact interaction between the anions at different temperatures was obtained. The electron spin density of each atom in the short distance contact interaction between free radical and anions and the overlap integral between their short distance contact atoms are obtained by theoretical calculation. The correlation between the electron spin density on the short distance contact atom and the overlap integral between the short distance contact atoms and the corresponding experimental magnetic coupling strength is discussed. The results are as follows: 1. It is shown for the first time that the greater the absolute value of the overlap integral between the atoms in short distance contact, the greater the antiferromagnetic coupling strength is. 2. It is revealed for the first time that the spin density and the relative overlap integral on the 蟺-蟺 overlap short distance contact pairs between free radicals are the two key factors leading to the antiferromagnetic coupling strength. It is further confirmed that the spin density of electrons on a pair of atoms in short distance contact is at the same time greater than 0.1, which is one of the necessary conditions for strong antiferromagnetic coupling between adjacent free radicals. The results of this paper will be helpful to the design and synthesis of molecular magnetic functional devices.
【学位授予单位】：山东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O641.4

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