High-Spin Polyphenoxyls Attached to Star-Shaped Poly(phenylenevinylene)s.
High-Spin Polyphenoxyls Attached to Star-Shaped Poly(phenylenevinylene)s.
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连接到星形聚（亚苯基亚乙烯基）上的高自旋聚苯氧基。
DOI：
10.1021/jo981090h
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
E. Tsuchida
中科院分区：
文献类型：
--
作者：
H. Nishide;M. Miyasaka;E. Tsuchida
以1，3，5-三碘苯或1，3，5-三(3‘，5’-二碘苯基)苯为核，以2-溴-4-(乙酰氧基苯基)苯乙烯为原料，经一锅Heck反应、水解、苯酚生成和多相氧化反应，合成了星形多侧基苯氧基(2和3)取代的聚(1，2-亚苯亚甲基)S(2和3)。ESR谱表明，星形分子的核心部分有离域自旋分布。在低温下，多自由基2和3处于高自旋态，且分子量越大，其铁磁性越强。虽然平均S为3/2到4/2，但多自由基2即使在自旋浓度为0.8自旋/单位的情况下也显示平均S为7/2到8/2。1，3，5-苯核起到了有效的磁偶联剂的作用，使悬挂的苯氧基的自旋通过星形的pi共轭主链排列。
Star-shaped poly(1,2-phenylenevinylene)s 4-substituted with multiple pendant phenoxyls (2 and 3) were synthesized by polymerizing 2-bromo-4-(acetoxyphenyl)styrene in the presence of 1,3,5-triiodobenzene or 1,3,5-tris(3',5'-diiodophenyl)benzene as the core via a simple one-pot Heck reaction and subsequent hydrolysis, phenolate formation, and heterogeneous oxidation. ESR spectra indicated a delocalized spin distribution into the core parts of the star-shaped molecules. The polyradicals, 2 and 3, were in a high-spin state at low temperature, and the ferromagnetic behavior was enhanced for the polyradical with a higher molecular weight. Although an average S of 3 remained at 3/2 to 4/2, the polyradical 2 even with a spin concentration of 0.8 spin/unit revealed an average S of 7/2 to 8/2. The 1,3,5-benzene core acted as an effective magnetic coupler to align the spins of the pendant phenoxyls through the star-shaped pi-conjugated backbone.