稀土夹心双酞菁铥的LB膜及其光谱特性

采用表面压-面积(π～A)等温曲线和紫外-可见吸收光谱研究了稀土夹心双酞菁铥(TmPc2)分子在Langmuir膜及其Langmuir-Blodgett(LB)膜中分子的排列状态和光谱特性。发现TmPc2分子在纯膜中以edge-on方式面对面的排列,在与花生酸(AA)的混合膜中TmPc2分子以face-on方式平躺排列。纯的TmPc2分子在亚相表面可以形成稳定的Langmuir膜,但不易转移到固体基片上,加入花生酸混合后不仅可以在亚相表面形成稳定的Langmuir膜,而且可以较好地转移到固体基片上,制成多层LB膜。TmPc2氯仿溶液和LB膜的紫外-可见吸收光谱具有明显的Soret吸收带和Q吸收带,Soret吸收带有2个吸收峰,分别对应184—187*和178—186的轨道电子跃迁。而Q吸收带有4个吸收峰,分别对应于186—189*,190*和185—187*,188*的轨道电子跃迁。由于分子间的相互作用,TmPc2分子在LB膜中紫外-可见吸收谱的各个吸收峰与氯仿溶液中的吸收峰相比较都发生了红移。层内分子的相互作用比层间分子的相互作用强。

Spectrum Properties of Thulium Bisphthalocyanine Langmuir-Blodgett Films

The configuration state and spectral properties of sandwiched thulium bisphthalocyanine (TmPc2) molecule in Langmuir films and Langmuir-Blodgett (LB) films were investigated by using the surface pressure-area (pi-A) isotherm and UV-Vis absorption spectra. The experimental results indicated that the sandwiched thulium bisphthalocyanine molecules form well-ordered stable monolayer films on the water/air interface, and the sandwiched thulium bisphthalocyanine molecules take the face to face orientation for the macrocycles and edge-on configuration in pure films, with the collapse pressure being 56 mN x m(-1). But the sandwiched thulium bisphthalocyanine molecules take the face-on configuration in the sandwiched thulium bisphthalocyanine films mixed with arachidic acid (AA), and the collapse pressure is more than 60 mN x m(-1). The sandwiched thulium bisphthalocyanine molecule could form well stable Langmuir films on sub-phase surface. The mixed TmPc2/arachidic acid not only could form well stable Langmuir films, but also could be transferred to solid substrate and deposited LB multilayers. In the chloroform solution and LB films of sandwiched thulium bisphthalocyanine, the UV-Vis absorption spectra have two absorption bands, namely Soret-bands and Q-bands. The electron orbit of sandwiched metal bisphthalocyanines was calculated by using absorption spectra VEH (Valence effective Hamiltonian) theory, and the electron transition orbit corresponding to the absorption peaks was analyzed. The Soret absorption band has two absorption peaks that are correlated with the electron orbital transitions of 184-187* and 178-186, and four absorption peaks of the Q absorption band are correlated with the electron orbital transitioned of 186-189*, 190* and 185-187*, 188*. In the LB films, the absorption peaks were red-shifted compared with those in the solution because of the interaction of molecules. The interaction of intra-layer molecules was stronger than that of interlayer molecules.