Distributions of Electron-Densities of Organic Magnetic Crystals

有机磁性晶体的电子密度分布

基本信息

批准号：
08454180
负责人：
IWASAKI Fujiko
金额：
$ 4.86万
依托单位：
The University of Electro-Communications
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08454180/
关键词：
crystal structure analysis electron-density distribution low temperature x-ray diffraction organic magnets organic radical crystals transition metal complexes multipole expansion method

项目摘要

The electron-density distributions of organic radical crystals and transition-metal complexes have been investigated using X-ray diffraction data measured at 100 K.Deformation electron-density distributions were calculated from the structure factors refined by the multipole expansion method.1. Some of the 4-Ar-CH=N-TEMPO radicals (TEMPO=2,2,6,6-tetramethylpiperidyl-1-oxyl), showed intermolecular ferromagnetic interactions at an extremely low temperature. In these crystals, the ferromagnetic interactions are transferred through O--- H van der Waals' interactions of beta-H atoms of the neighboring TEMPO rings. From the electron-density distributions, it was suggested that the unpaired electron of the 0 radical atom was located on the of the N-O bond. The beta-H atoms of the neighboring TEMPO rings contact with the 0 atom from the directions to avoid the lonepairs of the O atom and to prefer to the pi*-orbital.2. An unusually long radical N-O bond and a short intermolecular & O-O contact … More were observed in the crystals of 6,6-bis-(p-tolyl)-5,6-dihydro-phenanthridin-N-oxyl from the batch I . In the D-maps, significant peaks were observed on the O-O line. From the detailed refinements, a disordered structure, which contained a radical N-O bond and N-O-H bond forming an intermolecular O-H O hydrogen bond, were obtained, In the crystals from the batch II, the molecules showed the geometry of typical radicals, not showed a disordered structure. It is very interesting that the structure of the pure radical crystals are isomorphous with those constructed by the hydrogen-bonding.3. The electron density distributions of [Cu(II)(NO_3) _2 (pm) _3] (1) (ferromagnetic interaction) and [Cu(II)(NO_3)_2(pm)_2(H_2O)_2] (2) (antiferromagnetic interaction) (pm=pyrimidine) were investigated. The Cu atom in 1 is coordinated square pyramidally by two 0 atoms and three N atoms. In 2, it is coordinated octahedrally by four 0 atoms and two N atoms. For 2, six peaks are observed around the Cu atom, which show 3d electrons. Electron densities for lone-pairs of ligands are also clearly observed. Less

利用100 K下测量的X射线衍射数据研究了有机自由基晶体和过渡金属配合物的电子密度分布。通过多极展开法细化的结构因子计算了形变电子密度分布。 1． 4-Ar-CH=N-TEMPO 自由基（TEMPO=2,2,6,6-四甲基哌啶基-1-氧基），显示分子间在这些晶体中，铁磁相互作用通过邻近 TEMPO 环的 β-H 原子的 O--- H 范德华相互作用转移。 0基原子的不成对电子位于N-O键上，相邻TEMPO环的β-H原子从避免接触的方向与0原子接触。 O 原子的孤对原子，并且优先于 pi* 轨道。2. 在 6,6-bis-(p-tolyl)- 晶体中观察到了异常长的自由基 N-O 键和短的分子间 & O-O 接触……更多来自批次 I 的 5,6-二氢菲啶-N-氧基在 D-图中，在 O-O 线上观察到显着的峰。获得了含有自由基N-O键和形成分子间O-H O氢键的N-O-H键的无序结构，在来自批次II的晶体中，分子表现出典型自由基的几何形状，而不表现出非常无序的结构。有趣的是，纯自由基晶体的结构与氢键形成的结构是同晶的。3．[Cu(II)(NO_3) _2 (pm) _3]的电子密度分布。研究了 (1) (铁磁相互作用) 和 [Cu(II)(NO_3)_2(pm)_2(H_2O)_2] (2) (反铁磁相互作用) (pm=嘧啶) 1 中的 Cu 原子配位为四角锥体。在 2 中，它由四个 0 原子和两个 N 原子以八面体配位。对于 2，在 2 周围观察到六个峰。 Cu 原子，显示出孤对配体的电子密度。