Multiple Bistability in Quinonoid-Bridged Diiron(II) Complexes: Influence of Bridge Symmetry on Bistable Properties.
Multiple Bistability in Quinonoid-Bridged Diiron(II) Complexes: Influence of Bridge Symmetry on Bistable Properties.
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DOI：
10.1021/acs.inorgchem.6b02097
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发表时间：
2016-11
影响因子：
4.6
通讯作者：
Margarethe van der Meer;Yvonne Rechkemmer;Frauke D. Breitgoff;Raphael Marx;P. Neugebauer;Uta Frank;J. van Slageren;B. Sarkar
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文献类型：
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作者：
Margarethe van der Meer;Yvonne Rechkemmer;Frauke D. Breitgoff;Raphael Marx;P. Neugebauer;Uta Frank;J. van Slageren;B. Sarkar
五连桥非常适合于产生可能显示各种不同性质的双核组装体。在这篇文章中，我们提出了两种二铁（II）配合物，其中铁（II）中心要么通过对称取代的醌桥的双去质子形式2，5-双[4-]桥来桥接（异丙基）苯胺基]-1，4-苯醌（H2 L2 '）与[O，N，O，N]供体组，或与双去质子化形式的不对称取代的醌桥，2-[4-（异丙基）苯胺基]-5-羟基-1，4-苯醌（H2 L5 '）与[O，O，O，N]供体组。这两种配合物显示温度诱导的自旋交叉（SCO）。SCO的性质强烈依赖于桥连配体，只有具有[O，O，O，N]供体组的配合物显示出约55 K的显著滞后回线。重要的是，只有后者复合物也显示出明显的光诱导自旋状态变化。此外，这两种络合物都可以被氧化为混合价铁（II）-铁（III）形式，并且桥的性质决定了这些形式的Robin和Day分类。这两种配合物已被探测的电池的电化学，光谱和磁性的方法，这种结合的方法是用来阐明的电子结构的配合物和双稳态。因此，这里提出的结果表明，使用相对较新的类的不对称取代的桥接quinidine配体产生有趣的pinidine性能和进行特定位点的磁开关的潜力。
Quinonoid bridges are well-suited for generating dinuclear assemblies that might display various bistable properties. In this contribution we present two diiron(II) complexes where the iron(II) centers are either bridged by the doubly deprotonated form of a symmetrically substituted quinonoid bridge, 2,5-bis[4-(isopropyl)anilino]-1,4-benzoquinone (H2L2') with a [O,N,O,N] donor set, or with the doubly deprotonated form of an unsymmetrically substituted quinonoid bridge, 2-[4-(isopropyl)anilino]-5-hydroxy-1,4-benzoquinone (H2L5') with a [O,O,O,N] donor set. Both complexes display temperature-induced spin crossover (SCO). The nature of the SCO is strongly dependent on the bridging ligand, with only the complex with the [O,O,O,N] donor set displaying a prominent hysteresis loop of about 55 K. Importantly, only the latter complex also shows a pronounced light-induced spin state change. Furthermore, both complexes can be oxidized to the mixed-valent iron(II)-iron(III) form, and the nature of the bridge determines the Robin and Day classification of these forms. Both complexes have been probed by a battery of electrochemical, spectroscopic, and magnetic methods, and this combined approach is used to shed light on the electronic structures of the complexes and on bistability. The results presented here thus show the potential of using the relatively new class of unsymmetrically substituted bridging quinonoid ligands for generating intriguing bistable properties and for performing site-specific magnetic switching.