Bushby, Richard J.; Gooding, Daniel, Journal of the Chemical Society. Perkin Transactions 2 (2001), 1998, # 5, p. 1069 - 1075
作者:Bushby, Richard J.、Gooding, Daniel
DOI:——
日期:——
p-Doped high spin polymers1
作者:Richard J. Bushby、David R. Mcgill、Kai M. Ng、Norman Taylor
DOI:10.1039/a705076c
日期:——
High spin polymers have been created from p-doping of networked polyaryl and polyarylamine polymers which were synthesized using the Pd0 mediated coupling reaction of aryl di- and tri-bromides with aryl bis- and tris-boronic acids. The doping procedures produce polyradical polycations in which (in the limit of 100% doping) each spin is coextensive in its spatial distribution with three neighbouring spins. Magnetic susceptibility studies show the expected ferromagnetic spin-coupling. In this respect the best of these systems is the polymer obtained by the Pd0 mediated coupling of 1,3-dibromo-5-tetradecylbenzene with tris(4-boronic acid-2-hexyloxyphenyl)amine which was subsequently p-doped with NO+BF4– . A Brillouin function fit to the field dependence of the magnetization of this doped polymer at 2 K corresponds to an average spin S of 5/2. The best levels of doping achieved so far are about 15% of the theoretical maximum. These are sufficient to demonstrate the genuine high-spin nature of these polymers but are well short of the ca. 70% percolation limit needed for bulk superparamagnetic or ferromagnetic behaviour. The low doping levels are attributed to steric rather than coulombic effects.
高自旋聚合物是通过网络化聚芳基和聚芳胺聚合物的 p 掺杂制备的,这些聚合物是使用 PdO 介导的芳基二溴化物和三溴化物与芳基二硼酸和三硼酸的偶联反应合成的。掺杂过程产生多自由基聚阳离子,其中(在 100% 掺杂的限制下)每个自旋在其空间分布上与三个相邻自旋共同延伸。磁化率研究显示了预期的铁磁自旋耦合。在这方面,这些系统中最好的是通过 PdO 介导的 1,3-二溴-5-十四烷基苯与三(4-硼酸-2-己氧基苯基)胺的偶联获得的聚合物,随后用 NO+BF4 进行 p 掺杂– .适合该掺杂聚合物在 2 K 下磁化强度场依赖性的布里渊函数对应于 5/2 的平均自旋 S。迄今为止实现的最佳掺杂水平约为理论最大值的 15%。这些足以证明这些聚合物真正的高自旋性质,但远远低于大约。块体超顺磁或铁磁行为需要 70% 的渗透限制。低掺杂水平归因于空间效应而不是库仑效应。