Langmuir-Blodgett films of a clay mineral and ruthenium(II) complexes with a noncentrosymmetric structure.
Langmuir-Blodgett films of a clay mineral and ruthenium(II) complexes with a noncentrosymmetric structure.
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DOI：
10.1021/ja016005t
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发表时间：
2002-01
影响因子：
15
通讯作者：
Y. Umemura;A. Yamagishi;R. Schoonheydt;A. Persoons;F. D. De Schryver
中科院分区：
文献类型：
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作者：
Y. Umemura;A. Yamagishi;R. Schoonheydt;A. Persoons;F. D. De Schryver
用改进的Langmuir-Blodgett法制备了粘土矿物杂化的两亲分子[Ru(Phen)(2)(DcC12bpy)](2+)(phen=1，10-邻菲咯啉，dcC12bpy=4，4‘-羧氧基-2，2’-联吡啶双十二烷基酯)的单层和多层膜，并对其结构和性能进行了研究。通过表面压-分子面积(pi-A)等温线和原子力显微镜(AFM)观察，证实了Ru(II)络合阳离子与粘土片在空气-粘土悬浮液界面形成杂化单分子膜。通过在玻璃衬底上沉积杂化单分子膜来制备多层膜。多层膜中Ru(II)络合阳离子在492 nm处的吸光度随膜层数的增加而线性增加，表明杂化单层膜是逐层沉积的。由于多层膜的二次谐波(SHG)信号没有随膜层数的增加而增加，因此Ru(II)配位阳离子在膜中的取向会受到干扰。转移的杂化单层的亲水表面可以通过将其浸泡在十八烷基氯化铵(Odah(+)Cl(-))的水溶液中而转化为疏水表面。Odah(+)修饰的多层膜的倍频强度与层数呈二次曲线关系。这意味着通过表面性质的转换，多层膜中的Ru(II)配位阳离子成功地以非中心对称的方式取向。用外消旋混合物和Ru(II)络合阳离子的对映体考察了手性对膜性能的影响。Odah(+)修饰的多层膜增强了手性对倍频信号的贡献。
Mono- and multilayers of amphiphilic [Ru(phen)(2)(dcC12bpy)](2+) (phen = 1,10-phenanthroline, dcC12bpy = 4,4'-caboxyl-2,2'-bipyridyl didodecyl ester) hybridized with a clay mineral have been prepared by a modified Langmuir-Blodgett method, and their structures and properties have been investigated. Formation of a hybrid monolayer of the Ru(II) complex cations and the clay platelets at an air-clay suspension interface was confirmed by surface pressure-molecular area (pi-A) isotherm measurement and atomic force microscopic (AFM) observation. Multilayers were fabricated by depositing the hybrid monolayers onto glass substrates. The absorbance at 492 nm due to the Ru(II) complex cation in the multilayer increased linearly with the increase in the layer number, indicating layer-by-layer deposition of the hybrid monolayers. Because no increase in the second-harmonic generation (SHG) signal from the multilayers against the layer number was observed, the orientation of the Ru(II) complex cations in the layer would be disturbed. The hydrophilic surface of the transferred hybrid monolayer can be converted to a hydrophobic surface by dipping it in an aqueous solution of octadecylammonium chloride (ODAH(+)Cl(-)). The multilayers modified with ODAH(+) showed a quadratic relation between the SHG intensity and the layer number. This means that the Ru(II) complex cations in the multilayer are successfully oriented in a noncentrosymmetric way by the conversion of the surface property. Both a racemic mixture and an enantiomer of the Ru(II) complex cations were employed to examine the chiral effect on the film properties. The chiral contribution to the SHG signal was enhanced in the multilayer modified with ODAH(+).