Enhanced aggregation behavior of antimony(V) porphyrins in polyfluorinated surfactant/clay hybrid microenvironment
Enhanced aggregation behavior of antimony(V) porphyrins in polyfluorinated surfactant/clay hybrid microenvironment
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DOI：
10.1021/jp026648a
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发表时间：
2003-04-24
影响因子：
3.3
通讯作者：
Inoue, H
中科院分区：
文献类型：
--
作者：
Lucia, LA;Yui, T;Inoue, H
多氟化表面活性剂（CnF 2n +1CONH（CH 2）（2）N+（CH 3）（2）C16 H33 Br-;指定为CnF-S，其中n = 1-3）/粘土杂化化合物已显示在粘土夹层中提供具有分子尺寸的多氟化微腔。研究了水溶性卟啉（四（4-磺酸基苯基）卟啉合锑（V）; Sb（V）TSPP）与表面活性剂共插层在多氟微腔中的聚集行为。在这项研究中的关键发现之一是，Sb（V）TSPP分子的吸收光谱，插入在C3 F-S多氟表面活性剂/粘土杂化微结构的分散在苯中时急剧变化。观察到Sb（V）TSPP的单体Soret吸收带（422 nm）分裂成较长（438 nm）和较短（388 nm）波长分量。这些光谱变化取决于Sb（V）TSPP的吸附量，并可以占二聚体形成的基础上。的吸收和发射测量表明，两种类型的二聚体（J和H二聚体）中形成的多氟表面活性剂/粘土杂化夹层。还发现，当表面活性剂分子的吸附量减少时，即，随着中间层中多氟微腔体积的增大，Sb（V）TSPP的二聚化反应增强。在C2F-S和CIF-S多氟化/粘土混合化合物的情况下，观察到由二聚化引起的类似光谱行为。相反，在烃类似物（C3 H-S）和十六烷基三甲基溴化铵（CTAB）/粘土杂化化合物的情况下，Sb（V）TSPP产生的吸收和发射表明，它基本上保留了其单体特性。小角X-射线散射实验表明，间隙空间（层之间的距离）的混合化合物在苯中的增加相比，固体混合化合物。该结果表明苯分子渗透到混合层中。Sb（V）TSPP在多氟表面活性剂/粘土杂化物中的聚集机理为：（1）形成多氟界面层，界面层间的分子间相互作用很弱，（2）当苯溶剂分子渗透时，杂化物溶胀，Sb（V）TSPP在界面层中溶剂化;（3）Sb（V）TSPP分子从多氟化组装体排出到层间空间中;以及（4）Sb（V）TSPP分子迁移到微腔中，伴随着二聚体（H和J）的形成。
Polyfluorinated surfactant (CnF2n+1CONH(CH2)(2)N+(CH3)(2)C16H33Br-; designated as CnF-S, where n = 1-3)/clay hybrid compounds have been shown to provide polyfluorinated microcavities in the clay interlayers with molecular dimensions. The aggregation behavior of a water-soluble porphyrin (tetra(4-sulfonatophenyl)porphyrinatoantimony(V); Sb(V)TSPP) that cointercalates with the surfactant in the polyfluorinated microcavity was investigated. One of the key findings in this study was that the absorption spectra of Sb(V)TSPP molecules that intercalate in the C3F-S polyfluorinated surfactant/clay hybrid microstructures are drastically changed upon dispersion in benzene. The monomer Soret absorption band of Sb(V)TSPP (422 nm) was observed to split into both a longer (438 nm) and a shorter (388 nm) wavelength component. These spectral changes are dependent on the adsorbed amount of Sb(V)TSPP and can be accounted for on the basis of dimer formation. The absorption and emission measurements suggest that two types of dimers (J and H dimers) are formed in the polyfluorinated surfactant/clay hybrid interlayers. It was also found that when the adsorbed amount of surfactant molecules decreased, i.e., when the volume of the polyfluorinated microcavity in the interlayer increased, then the dimerization of Sb(V)TSPP was enhanced. In the case of C2F-S and CIF-S polyfluorinated/clay hybrid compounds, similar spectral behavior arising from dimerization was observed. In contrast, in the case of the hydrocarbon analogues (C3H-S) and cetyltrimethylammonium bromide (CTAB)/clay hybrid compounds, the absorption and emission arising from Sb(V)TSPP indicates that it essentially retains its monomer character. Small-angle X-ray scattering experiments revealed that the clearance space (distance between the layers) for the hybrid compounds in benzene increases compared to that of the solid hybrid compounds. This result indicates a penetration of the benzene molecules into the hybrid layers. It is proposed that the aggregation mechanism of Sb(V)TSPP in polyfluorinated surfactant/clay hybrid compounds obeys the following sequence: (1) formation of a polyfluorinated environment of interlayers that have very weak intermolecular interactions among the surfactant molecules; (2) upon penetration of the benzene solvent molecules, swelling of the hybrid compounds and solvation of Sb(V)TSPP in the interlayers; (3) expulsion of Sb(V)TSPP molecules from the polyfluorinated assemblies into the interlayer space; and (4) migration of Sb(V)TSPP molecules to the microcavities, with concomitant dimer (H and J) formation.