Controlled Storage of Ferrocene Derivatives as Redox-Active Molecules in Dendrimers
Controlled Storage of Ferrocene Derivatives as Redox-Active Molecules in Dendrimers
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DOI：
10.1021/ja9064377
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发表时间：
2010-04-14
影响因子：
15
通讯作者：
Yamamoto, Kimihisa
中科院分区：
文献类型：
--
作者：
Ochi, Yousuke;Suzuki, Mana;Yamamoto, Kimihisa
树突状多苯基甲基亚胺（DPA）可以通过与DPA亚胺的供电子骨架络合包裹二茂铁。将二茂铁加入到一系列枝状多苯基甲基亚胺（DPAGX，其中X为代数，X= 1-4）中，紫外-可见光谱的变化与金属离子与DPAGX络合时的变化相似。第4代树状大分子（DPAG4）的第1层和第2层亚胺基团的数量一致地观察到等共吸点的逐步变化。DPAG2和DPAG3也捕获了6等量的二茂铁。采用紫外可见光谱、Fe-57穆斯堡尔光谱、电喷雾电离质谱（ESI-MS）、循环伏安法（CV）和荧光光谱研究络合作用。我们证实了中性二茂铁不能与亚胺基络合，而二茂铁可以。利用二茂铁的氧化还原特性，我们能够电化学控制二茂铁的包封和释放到DPA中，其方式类似于氧化还原反应蛋白（如铁蛋白）。除了二茂铁外，低二茂铁也可以被捕获在DPA中。双二茂离子（1+）具有稳定的混合价态，特别适合于电化学开关。封装在DPAG4中的二茂铁二价态（2+）可以制成薄膜，薄膜表现出价间电荷转移（IV-CT）带的近红外吸收，为该体系在材料科学中的应用指明了方向。
Dendritic polyphenylazomethines (DPA) could encapsulate ferroceniums by complexation of the electron-donating skeleton of the DPA imines. Upon addition of ferroceniums to a series of dendritic polyphenylazomethines (DPAGX, where Xis the generation number, X= 1-4), the UV-vis spectra showed changes in a manner similar to that observed for the complexation of metal ions with DPAGX. Stepwise shifts in the isosbestic point were consistently observed with the number of imine groups in the first and second layers of the generation-4 dendrimer (DPAG4). DPAG2 and DPAG3 were also found to trap 6 equiv of ferroceniums. To investigate the complexation, UV-vis spectroscopy, Fe-57 Mossbauer spectroscopy, electrospray ionization-mass spectroscopy (ESI-MS), cyclic voltammetry (CV), and fluorescence spectroscopy were performed. We confirmed that neutral ferrocenes cannot complex with the imine group while ferroceniums can. Utilizing the redox property of ferrocenes, we were able to electrochemically control the encapsulation and release of ferrocenes into the DPA in a manner similar to redox-responsive proteins such as ferritin. In addition to ferrocenes, oligoferrocenes could also be trapped in the DPA. The biferrocene cation(1+) was particularly suitable for electrochemical switching due to its stable mixed valence condition. The terferrocene dication(2+) encapsulated into DPAG4 could be fabricated into a thin film, which exhibited the near-infrared absorption of an intervalence charge-transfer (IV-CT) band, pointing the way toward the use of such systems in material science.