Preparation of lamellar inorganic–organic hybrids from tetraethoxysilane and a coumarin derivative containing a triethoxysilyl group and photodimerization of the interlayer coumarin groups
作者:Shintaro Nasu、Ayako Tsuchiya、Kazuyuki Kuroda
DOI:10.1039/c0jm00407c
日期:——
Lamellar inorganicâorganic hybrids were prepared as powders and films via hydrolysis and cocondensation of tetraethoxysilane (TEOS) and a coumarin derivative containing a triethoxysilyl group. The formation of lamellar structures consisting of siloxane layers and interlayer coumarin groups with ca. 4 nm periodicities, revealed by XRD and TEM, is induced by self-assembly of the oligomeric species derived from TEOS and the derivative. The UVâvis absorption spectrum of the as-synthesized hybrid film showed an absorption maximum blue-shifted from that observed for a CHCl3 solution of the monomeric coumarin derivative, which supports the formation of a face-to-face structure of the interlayer coumarin groups. Dimerization of the coumarin groups occurred by irradiation with visible light (>310 nm). The groups in the lamellar hybrid film showed faster dimerization and the yield of dimers was higher, if compared with those in a disordered hybrid film and the neat coumarin derivative, indicating the efficient dimerization of the chromophores with a controlled arrangement. The molecular design of a coumarin derivative strongly influences the property of hybrids as well as the mesostructural formation.
通过四乙氧基硅烷(TEOS)和含有三乙氧基硅烷基团的香豆素衍生物的水解和共缩聚反应,制备出片状的无机-有机杂化粉末和薄膜。XRD和TEM显示,由硅氧烷层和层间香豆素基团组成的片状结构具有约4 nm的周期性,这是由TEOS和衍生物衍生的低聚物自组装引起的。合成杂化薄膜的紫外-可见吸收光谱显示,吸收峰的最大值比单体香豆素衍生物的CHCl3溶液观察到的吸收峰最大值蓝移,这支持了层间香豆素基团面对面结构的形成。香豆素基团在可见光(>310 nm)照射下发生二聚化。与无序杂化薄膜和纯净香豆素衍生物相比,片状杂化薄膜中的基团二聚化更快,二聚体产量更高,这表明具有可控排列的色原子的二聚化效率更高。香豆素衍生物的分子设计强烈影响杂化物的性质以及中间结构的形成。