Synthesis of ferrocenethiols containing oligo(phenylenevinylene) bridges and their characterization on gold electrodes
Synthesis of ferrocenethiols containing oligo(phenylenevinylene) bridges and their characterization on gold electrodes
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DOI：
10.1021/ja0043340
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发表时间：
2001-08-22
影响因子：
15
通讯作者：
Chidsey, CED
中科院分区：
文献类型：
--
作者：
Dudek, SP;Sikes, HD;Chidsey, CED
通过苯单体的正交偶联制备了二茂铁封端的低聚（苯撑乙烯撑）（OPV）甲基硫醇。苯环上的乙氧基取代基改善了OPV的溶解度，使得能够合成较长的低聚物。将含有二茂铁OPV甲基硫醇和稀释剂烷醇的混合物的自组装单分子膜沉积在金上。含有相同长度的低聚物的单分子膜的循环伏安法研究与乙氧基增溶基团和不增溶的低聚物显示，溶解和不溶解的低聚物形成良好的包装自组装单分子膜。改变增溶基团在低聚物链上的位置并不妨碍低聚物在单层中的堆积。传统的计时电流法可用于测量高达10（4）s（-1）的速率常数，但太慢而不能测量在高达35埃的距离内通过这些低聚物的电子转移速率。预期OPV桥是高度共辄的，不像低聚（亚苯基亚乙炔基）桥，低聚（亚苯基亚乙炔基）桥由于苯环围绕亚乙炔基键旋转而可能仅部分共辄。由于其高共轭性，OPV可能被证明可用作分子导线。
Ferrocene-terminated oligo(phenylenevinylene) (OPV) methyl thiols have been prepared by orthogonal coupling of phenylene monomers. Ethoxy substituents on the phenyl rings improve the solubility of OPV, enabling the synthesis of longer oligomers. Self-assembled monolayers containing a mixture of a ferrocene OPV methyl thiol and a diluent alkanethiol were deposited on gold. A cyclic voltammetric study of monolayers containing oligomers of the same length with and without ethoxy solubilizing groups reveals that both solubilized and unsolubilized oligomers form well-packed self-assembled monolayers. Changing the position of the solubilizing groups on an oligomer chain does not preclude packing of the oligomer in the monolayer. Conventional chronoamperometry, which can be used to measure rate constants up to similar to 10(4) s(-1), is too Slow to measure the electron-transfer rate through these oligomers over distances up to 35 Angstrom. OPV bridges are expected to be highly conjugated unlike oligo(phenyleneethynylene) bridges, which may be only partially conjugated because of rotation of the phenyl rings about the ethynylene bonds. Because of its high conjugation, OPV may prove useful as a molecular wire.