Molecular Architecture: Construction of Self-Assembled Organophosphonate Duplexes and Their Electrochemical Characterization
Molecular Architecture: Construction of Self-Assembled Organophosphonate Duplexes and Their Electrochemical Characterization
复制标题
DOI：
10.1021/la301610a
复制
发表时间：
2012-05-22
期刊：
影响因子：
3.9
通讯作者：
Tornow, Marc
中科院分区：
文献类型：
--
作者：
Cattani-Scholz, Anna;Liao, Kung-Ching;Tornow, Marc
在纳米SiO2修饰的高掺杂硅电极上合成了11-羟基十一烷基膦酸、2，6-二膦基蒽、9，10-二苯基-2，6-二膦基蒽和10，10 '-二膦基-9，9'-二蒽的自组装单分子膜和一种新型的自组装有机膦酸双分子系。通过首先处理由芳族二膦酸制备的SAMP以形成钛络合物封端的SAMP来合成双重系综;随后添加第二当量的芳族二膦酸。SAMP的均匀性，粗糙度和厚度进行了评价，通过原子力显微镜，SAMP膜的厚度和结构的贡献，每个单元中的双用X射线反射（XRR）进行了测量。将双链体与脂肪族和芳香族单层SAMP进行比较，以确定堆叠对电化学性能的影响;这些通过使用水性电解质在20 Hz至100 kHz的频率范围内进行阻抗谱测量，并使用基于等效电路的电阻电容网络分析数据。对于11-羟基十一烷基膦酸盐SAMP，C-SAMP = 2.6 +/- 0.2 μ F/cm（2），与其测得的层厚度（约0.5 μ F/cm（2））一致。1.1 nm）。对于蒽基SAMP，C-SAMP = 6-10 μ F/cm（2），这主要归因于芳族部分的较高有效介电常数（ε = 5-10）;阻抗谱测量双链体中第二芳香族单层（2ndSAMP）的附加电容为C-Ti/2ndSAMP = 6.8 +/- 0.7 μ F/cm（2），与第一个串联。
Self-assembled monolayers of phosphonates (SAMPs) of 11-hydroxyundecylphosphonic acid, 2,6-diphosphonoanthracene, 9,10-diphenyl-2,6-diphosphonoanthracene, and 10,10'-diphosphono-9,9'-bianthracene and a novel self-assembled organophosphonate duplex ensemble were synthesized on nanometer-thick SiO2-coated, highly doped silicon electrodes. The duplex ensemble was synthesized by first treating the SAMP prepared from an aromatic diphosphonic acid to form a titanium complex-terminated one; this was followed by addition of a second equivalent of the aromatic diphosphonic acid. SAMP homogeneity, roughness, and thickness were evaluated by AFM; SAMP film thickness and the structural contributions of each unit in the duplex were measured by X-ray reflection (XRR). The duplex was compared with the aliphatic and aromatic monolayer SAMPs to determine the effect of stacking on electrochemical properties; these were measured by impedance spectroscopy using aqueous electrolytes in the frequency range 20 Hz to 100 kHz, and data were analyzed using resistance capacitance network based equivalent circuits. For the 11-hydroxyundecylphosphonate SAMP, C-SAMP = 2.6 +/- 0.2 mu F/cm(2), consistent with its measured layer thickness (ca. 1.1 nm). For the anthracene-based SAMPs, C-SAMP = 6-10 mu F/cm(2), which is attributed primarily to a higher effective dielectric constant for the aromatic moieties (epsilon = 5-10) compared to the aliphatic one; impedance spectroscopy measured the additional capacitance of the second aromatic monolayer in the duplex (2ndSAMP) to be C-Ti/2ndSAMP = 6.8 +/- 0.7 mu F/cm(2), in series with the first.