Department of Organic Chemistry, Weizmann Institute of Science, 76100 Rehovot, Israel.
Chemistry. 2013 Jul 1;19(27):8821-31. doi: 10.1002/chem.201300034. Epub 2013 May 16.
Molecular assemblies (MAs) of oligofurans and oligothiophenes were formed from solutions on various substrates. These films were obtained by alternating deposition of organic chromophores (oligofurans or oligothiophenes) and a palladium salt. These coordination-based MAs were characterized by UV/Vis spectroscopy, spectroscopic ellipsometry, atomic force microscopy (AFM), X-ray reflectivity (XRR), X-ray photoelectron spectroscopy (XPS), and electrochemistry. The MAs exhibit similar electrochemical behavior and their growth and structure are apparently not affected when different organic template layers are used. The density of the MAs is a function of the structure of the molecular component. The oligothiophene density is approximately 50% higher than that observed for the oligofuran-based assemblies. The optical and electrochemical properties of the MAs scale linearly with their thickness. The UV/Vis data indicate that upon increasing the film thickness, there is no significant conjugation between the metal-separated organic chromophores. DFT calculations confirmed that the HOMO-LUMO gap of the surface-bound oligofuran and oligothiophene metal oligomers do not change significantly upon increasing their chain length. However, electrochemical measurements indicate that the susceptibility of the MAs towards oxidation is dependent on the number of chromophore units.
寡呋喃和寡噻吩的分子组装体（MAs）从各种基底上的溶液中形成。这些薄膜是通过交替沉积有机发色团（寡呋喃或寡噻吩）和钯盐获得的。这些基于配位的 MAs 通过紫外/可见光谱、光谱椭圆偏振术、原子力显微镜（AFM）、X 射线反射率（XRR）、X 射线光电子能谱（XPS）和电化学进行了表征。这些 MAs 表现出相似的电化学行为，当使用不同的有机模板层时，其生长和结构显然不受影响。MAs 的密度是分子组成部分结构的函数。寡噻吩的密度比基于寡呋喃的组装体观察到的密度高约 50%。MAs 的光学和电化学性质与其厚度呈线性关系。紫外/可见数据表明，随着膜厚度的增加，金属分离的有机发色团之间没有明显的共轭。DFT 计算证实，表面结合的寡呋喃和寡噻吩金属寡聚物的 HOMO-LUMO 能隙在增加其链长时不会发生显著变化。然而，电化学测量表明，MAs 对氧化的敏感性取决于发色团单元的数量。
