Site-specific synthesis of oxo-bridged mixed-valence binuclear complexes on mesoporous silica.
Site-specific synthesis of oxo-bridged mixed-valence binuclear complexes on mesoporous silica.
复制标题
介孔二氧化硅上氧桥混合价双核配合物的位点特异性合成。
DOI：
10.1021/la704032c
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
K. Hashimoto
中科院分区：
文献类型：
--
作者：
A. Okamoto;Ryuhei Nakamura;H. Osawa;K. Hashimoto
我们报道了在有序介孔氧化硅（SBA-15）的孔内定点合成混合价TiIV-O-FeII配合物。以6-二叔丁基吡啶为钛接枝SBA-15分子中三足连接的TiIV-OH基团的选择性活化剂，FeCl_2·4 H_2 O配合物选择性地与亲核TiIV-O（-）基团反应。由于与丰富的Si-OH基团的反应，Si-O-FeII副产物的形成被成功地限制，并且形成TiIV-O-FeII络合物的选择性超过80%。TiIV/Fe Ⅱ--> TiIII/Fe Ⅲ金属-金属电荷转移带的出现证实了TiIV-O-Fe Ⅱ配合物的金属-金属相互作用，并通过漫透射紫外-可见光谱、傅里叶变换红外光谱和Fe K边X射线吸收精细结构测量表征了它们的配位、价态和自旋状态。还证实了本方法可以扩展到TiIV-O-NiII和TiIV-O-MnII的其他金属组合。氧桥混合价络合物在二氧化硅载体上的光诱导金属-金属电荷转移过程是一类新的可见光敏感氧化还原中心。因此，本合成程序允许根据分子水平设计制造各种光化学反应中心。
We report the site-specific synthesis of mixed valence TiIV-O-FeII complexes within the pores of ordered mesoporous silica (SBA-15). By using 6-di- tert-butylpyridine as the selective activator of tripodally linked TiIV-OH groups of Ti-grafted SBA-15, the FeCl2.4H2O complexes reacted selectively with the nucleophilic TiIV-O(-) groups. The formation of Si-O-FeII byproducts, due to the reaction with the abundant Si-OH groups, was successfully restricted and the selectivity for forming the TiIV-O-FeII complexes exceeded 80%. The metal-metal interaction of TiIV-O-FeII complexes was confirmed by the appearance of TiIV/FeII --> TiIII/Fe III metal-to-metal charge transfer band, and their coordination, valency, and spin state were characterized by diffuse transmission UV-vis, Fourier transform IR, and Fe K-edge X-ray absorption fine structure measurements. It was also confirmed that the present methods can be extended to other metal combinations of TiIV-O-NiII and TiIV-O-MnII. The electron transfer processes occurring under photoinduced metal-to-metal charge transfer of oxo-bridged mixed valence complexes on silica supports have recently been proven as a new class of visible-light-sensitive redox centers. Thus, the present synthetic procedure allows the fabrication of a variety of photochemical reaction centers according to the molecular-level design.