Ferromagnetic spin alignment in head-to-tail coupled oligo(1, 4-phenyleneethynylene)s and Oligo(1,4-phenylenevinylene)s bearing pendant p-phenylenediamine radical cations
Ferromagnetic spin alignment in head-to-tail coupled oligo(1, 4-phenyleneethynylene)s and Oligo(1,4-phenylenevinylene)s bearing pendant p-phenylenediamine radical cations
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头尾耦合寡聚(1, 4-亚苯基乙炔基) 和带有悬垂对苯二胺自由基阳离子的寡聚(1,4-亚苯基亚乙烯基) 中的铁磁自旋排列
DOI：
10.1021/jo000548o
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Janssen
中科院分区：
文献类型：
--
作者：
van Meurs PJ;Janssen
描述了对苯基二胺自由基阳离子在分子内和分子间的远端铁磁偶联（1,4-苯基乙烯）s和对苯基二胺（1,4-苯基乙烯）s的头尾偶联。紫外/可见/近红外实验表明，自由基阳离子定位在共轭低聚物的对苯二胺上。这些低聚（1,4-苯乙烯）和低聚（1,4-苯乙烯）二（自由基阳离子）的ESR光谱与三态相一致。DeltaM(s) = +/-1和DeltaM(s) = +/-2信号的双积分ESR强度与逆温度（I约为1/T）呈线性关系，符合居里定律。这种行为表明具有较大的三重态-单线态能隙的三重态基态双自由基，或者可能是单线态和三重态的简并。
The intramolecular and long-range ferromagnetic coupling between p-phenylenediamine radical cations in head-to-tail coupled oligo(1, 4-phenyleneethynylene)s and oligo(1,4-phenylenvinylene)s between neighbors and next-nearest neighbors is described. UV/vis/near-IR experiments show that the radical cations are localized in the pendant p-phenylenediamine units of the conjugated oligomers. The ESR spectra of these oligo(1,4-phenyleneethynylene) and oligo(1, 4-phenylenvinylene) di(radical cation)s are consistent with those of a triplet state. A linear behavior is observed for the doubly integrated ESR intensity of the DeltaM(s) = +/-1 and DeltaM(s) = +/-2 signals with the inverse temperature (I approximately 1/T), consistent with Curie's law. This behavior indicates a triplet ground-state diradical with a large triplet-singlet energy gap or possibly a degeneracy of singlet and triplet states.