卟啉类L-B膜分子间相互作用的光谱研究

STUDIES ON SPECTRA OF PORPHYRIN INTERMOLECULAR INTERACTIONS IN L-B FILM

以无取代的meso-四-(4-N)-吡啶基卟啉及其过渡族金属(主要Cu^(2+)、Zn^(2+))络合物制备L-B膜,以近紫外-可见吸收光谱和荧光光谱为手段,研究叶啉类分子在氯仿溶液中,L-B膜状态下以及固态状态下的相互作用。探讨分子聚集体的存在对光谱性质的影响。 为了研究叶咻类分子间的相互作用及其对光谱性质的影响,我们首先分析了叶啉在CHCl_3溶液中及固态状态下的近紫外-可见吸收光谱和荧光光谱。并将其与叶啉类分子的L-B膜作比较。结果表明,卟啉类的Soret吸收带带宽及峰位置在三种状态下均不相同,L-B膜的情况介于溶液中的和固体下的情况之间,说明了在L-B膜中,卟啉分子存在着某种形式的聚集体,且在这种聚集体中分子间的相互作用程度比固体弱,可以认为L-B膜上的分子呈准晶体状态。

Pure Lanpmuir-Blodgett film of non-alkyl-substituted porphyrins-such as meso-tetra-(4-N)-pyridyl-porphyrin (H2TPyP) and its Zn2+, Cu2+ complexes (ZnTPyP), (CuTPyP) are described. The porphyrin intermolecular interactions in chloroform solution, in L-B film and in the solid state were investigated by means of near UV absorption spectroscopy and fluorescence spectroscopy. The molecular aggregate effect on the spectra was discussed.We first analyzed near-UV absorption and fluorescence spectra of porphytins in chloroform solution and in the solid state and compared them with that in L-B film so as to study the porphyrin intermolecular interactions and their effects on the spectra. It was shown that the Soret band of porphyrins has different half band width and peak wavelength in the three cases. The case in the L-B film is just situated between the other two. It may be considered that there is some form of porphyrin molecular aggregate in the L-B film, and the intermolecular interactions within the aggregate are weaker than that in the solid state. Therefore, it could be concluded that the porphyrin molecules exist in a state of quasi-crystal in the L-B film.