荧光发色团插层镁铝水滑石的制备和光物理性质

Preparation and Photophysical Properties of Chromophores Pillared Mg-Al-LDH

以层状镁铝水滑石[Mg 0.66 Al 0.34(OH)2](CO3)0.17.0.67H2O为主体,通过离子交换法,分别将乙基橙(EO-)和4-氨基偶氮苯基-4-磺酸阴离子(4A-)插入到层状镁铝水滑石层间和吸附在镁铝水滑石表面.插层产物及表面吸附产物分别采用XRD、IR、TG-DTA等测试技术进行结构表征,采用UV-Vis吸收光谱和荧光光谱研究其光谱特征.并用G03w软件包中ab initio分子轨道法(HF/6-31G)计算了客体分子结构和电荷分布,认为客体阴离子以单层形式垂直排布于层板之间.结果表明,客体进入层间后,由于客体与主体的相互作用,在限域空间内客体微环境的改变造成荧光发射强度发生改变,与纯客体相比EO插层产物的荧光强度提高,而4A插层产物的荧光发射强度却大大减弱,EO与4A的吸附产物荧光发射强度均降低,说明通过主体与客体或客体与客体的相互作用可以改变客体的光物理性质.

Ethyl orange （EO-） and 4-aminoazobenzene-4-sulfonic anion（4A-） were intercalated into the layered double hydroxide （LDH）, [Mg0.66Al0.34（OH）2]（CO3）0.17·0.67H2O or exchanged on the external surface of the host by the method of ion-exchange procedures. The obtained compounds were characterized by X-ray diffraction, infrared and thermogravimetry techniques. The photophysical properties of the obtained compounds were studied by UV-Vis absorption and fluorescence spectroscope. The guest molecular sizes and structures were investigated util- izing an ab initio （HF/6-31G） method by G03w. These anions were arranged in the interlayer space as a monolayer of species with the main axis perpendicular to the layer plane. These results indicated that the fluorescence of intercalated sample of Mg-A1-EO-LDH increased greatly due to a more rigid and constrained environment of the host. However, the fluorescence of intercalated sample of Mg-Al-4A-LDH decreased due to the concentration quenching. Compared with those observed in the pure microcrystalline EO and 4A, the fluorescence intensity of the samples containing only surface-exchanged EO or 4A reduced because the charge transfer between EO or 4A molecules was enhanced. It suggests that the photophysical properties of guests can be changed by the guest-host interaction or guest-guest interaction.