Magnetic Property of Polymer-Rare Earth Complexes

目的是制备具有稀土离子的聚合物配合物，其中聚合物结合离子之间预期存在自旋-自旋相互作用，并研究其与基质结构相关的磁性。用电位滴定法研究了稀土离子Eu、Tb、Sm与甲基丙烯酸丙烯酰胺共聚物和聚氧乙烯接枝聚甲基丙烯酸的络合作用。共聚物形成的[稀土离子（羧酸根）3]配合物具有较大的配合物形成常数。络合过程中的熵变很大，有利于稳定络合物的形成。络合作用受配位距离、聚合物链的柔性和水合作用的影响。与甲基丙烯酸和丙烯酸酯共聚物的复合物得到透明和柔性的膜。可见吸收光谱和荧光光谱表明，稀土离子在薄膜中形成了三配位配合物，且配合离子均匀分散在薄膜中。Gd配合物薄膜具有顺磁性。为了改善聚合物配合物的结构，合成了具有共轭结构的聚吡啶亚甲基三氮和聚吡咯啉配体，并与Eu、Gd、Fe离子进行了配合。<alpha>Gd配合物是顺磁性的。另一方面，相应的铁配合物显示出较强的铁磁性。穆斯堡尔参数表明，痕量的铁氧化物污染的聚合物复合物和明确的聚合物基体保护铁氧化物作为超细颗粒在其域。如上所述，通过使用高分子-稀土配合物，获得了接近高分子磁性物质的新结果。

The objective is to prepare polymer complexes with rare earth ions in which a spin-spin interaction is expected between the polymer-bound ions and to study their magnetic property in connection with the matrix structure. Complexation of copolymer of methacrylic acid and acrylamide and of polyethyleneoxide-grafted polymethacrylic acid with rare earth ions such as Eu, Tb, and Sm was studied by potentiometric titration using modified Bjerrum's method. The copolymers formed the [rare earth ion (carboxylate)3] complex with large complex formation constants. Very large entropy change in the complexation contributed to the stable complex formation. The complexation was affected by distance between coordination sites and flexibility and hydration of the polymer chain. The complexes with the copolymers of methacrylic acid and acrylate gave transparent and flexible films. Visible absorption and fluorescent spectroscopy indicated that the rare earth ions formed the tris-coordinate complexes even in the films and the complexed ion were uniformly dispersed in the films. The Gd complex films showed paramagnetism. In order to improve the structure of polymer complexes, polypyridilenemethylidenenitrio and poly- <alpha> -pyrralenine were synthesized as polymer ligands with conjugated structure and were complexed with Eu, Gd, and Fe ion. The Gd complexes were paramagnetic. On the other hand, the corresponding Fe complexes showed strong ferromagnetism. Moessbauer parameters suggested that a trace ofiron oxides contaminated the polymer complexes and that the definite polymer matrices protectediron oxides as ultra fine particles in their domain. As mentioned above, new results to approach a polymeric magnetic substance were obtained by using the polymer-rare earth complexes.