Different Antiferromagnetic Coupling between 5,5’- and 10,10’-Linked Iron(III) Corrole Dimers
Different Antiferromagnetic Coupling between 5,5’- and 10,10’-Linked Iron(III) Corrole Dimers
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5,5- 和 10,10- 连接铁 (III) Corrole 二聚体之间的不同反铁磁耦合
DOI：
10.1002/ejic.201601363
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发表时间：
2017
影响因子：
2.3
通讯作者：
Masashi Takahashi Atsuhiro Osuka
中科院分区：
文献类型：
--
作者：
Takayuki Tanaka;Shota Ooi;Yuki Ide;Takahisa Ikeue;Masaaki Suzuki;Peter P.-Y. Chen;Masashi Takahashi Atsuhiro Osuka
两个FeIIIcorrole通过不同位置的单一介观连接，即5，5 ′-连接和10，10 ′-连接，这导致了两个铁（III）corrole单元之间的位置依赖性反铁磁相互作用的观察。根据1H NMR谱、居里曲线、穆斯堡尔谱和超导量子干涉仪（SQUID）测量，在环境条件下发现铁（III）中心呈现中间自旋态，S= 3/2。在以前的报道中，联吡啶三（五氟苯基）可络铁（III）的X射线结构被指定为六配位物种，但10，10 ′-连接和5，5 ′-连接的二聚体在固态下更倾向于五配位几何构型。此外，还得到了混合的五配位/六配位二聚体，这意味着配位模式对晶体堆积力的敏感性。通过总结结果，可以得出结论，吡啶-三（五氟苯基）铁（III）可咯在甲苯中的环境条件下可以更好地描述为五配位、中间自旋（S= 3/2）物种，而在低温下与更强的轴向配体（如咪唑）配位时，六配位低自旋（S= 1/2）铁（III）络合物的主要贡献出现。作为对这些解释的补充，10，10 ′-连接的二聚体在两个铁（III）络合物之间表现出比5，5 ′-二聚体更大的反铁磁相互作用（J= -0.64 cm-1）。
Two FeIIIcorroles were connected through a singlemeso–mesolinkage at different positions, that is, 5,5′‐linkage and 10,10′‐linkage, which led to the observations of position‐dependent antiferromagnetic interactions between the two iron(III) corrole units. The iron(III) centers were found to exhibit an intermediate‐spin state,S= 3/2, under ambient conditions on the basis of1H NMR spectra, Curie plots, Mössbauer spectroscopy, and super‐conducting quantum interference device (SQUID) measurements. In previous reports, the X‐ray structure of dipyridine tris(pentafluorophenyl)corrolato iron(III) was assigned as a six‐coordinate species, but the 10,10′‐linked and 5,5′‐linked dimers preferred five‐coordinate geometry in the solid state. In addition, a mixed five‐coordinate/six‐coordinate dimer was also obtained, implying a susceptibility of the coordination mode to the crystal packing force. By summarizing the results, it can be concluded that pyridinate–iron(III) tris(pentafluorophenyl)corroles can be better described as five‐coordinate, intermediate‐spin (S= 3/2) species under ambient conditions in toluene, whereas a dominant contribution of six‐coordinate low‐spin (S= 1/2) iron(III) complex appears when coordinated with stronger axial ligands such as imidazole at low temperature. Complementary to these interpretations, the 10,10′‐linked dimer exhibited a larger antiferromagnetic interaction between the two iron(III) corroles (J= –2.04 cm–1) than that of the 5,5′‐dimer (J= –0.64 cm–1).