Seo Kyoungja, Jeon Il Cheol, Yoo Dong Jin
Department of Chemistry, Chonbuk National University, Jeonju, Chonbuk 561-756, Korea.
Langmuir. 2004 May 11;20(10):4147-54. doi: 10.1021/la0208068.
The electrochemical characteristics of the modified electrodes with ferrocenecarboxylate-coupled aminoundecylthiol monolayers prepared in two sequential steps were studied. The self-assembled monolayer (SAM) was prepared through the covalent attachment of ferrocenecarboxylate in an activation solution containing N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide coupling agent to aminoundecylthiol SAMs formed on a substrate. In the ferrocenecarboxylate-coupled aminoundecylthiol monolayers, the ferrocene moieties were expected to be packed regularly with enhanced ordering compared with those in the FcCOO(CH2)11SH monolayer. As the ferrocene coverage increases, the formal potential for the ferrocene-ferricenium (Fc/Fc+) couple shifts to the positive potential and the full width at half-maximum (deltaE(fwhm)) increases also. The maximum coverage is found to be about 3 x 10(-10) mol cm(-2), which is considered to be a value obtained from a well-ordered ferrocene-tethered SAM. As for the mass change, the increase in ferrocene coverage caused the enhancement in ion association between the ferricenium cations and perchlorate anions resulting in a mass increase upon oxidation; however, the mass change per mole electron decreases. The results obtained from the ferrocenecarboxylate-coupled aminoundecylthiol monolayers were explained to be due to the well-ordered packing with regular spacing compared with those of the FcCOO(CH2)11SH monolayer.
研究了分两步制备的、具有二茂铁羧酸盐偶联氨基十一烷基硫醇单层的修饰电极的电化学特性。通过在含有N-(3-二甲基氨基丙基)-N'-乙基碳二亚胺偶联剂的活化溶液中，将二茂铁羧酸盐共价连接到在基底上形成的氨基十一烷基硫醇自组装单层（SAM）上，制备了自组装单层。在二茂铁羧酸盐偶联氨基十一烷基硫醇单层中，与FcCOO(CH2)11SH单层中的二茂铁部分相比，预期二茂铁部分会以增强的有序性规则排列。随着二茂铁覆盖率的增加，二茂铁-二茂铁鎓（Fc/Fc+）电对的形式电位向正电位移动，半高宽（deltaE(fwhm)）也增加。发现最大覆盖率约为3×10(-10) mol cm(-2)，这被认为是从有序的二茂铁连接的SAM获得的值。至于质量变化，二茂铁覆盖率的增加导致二茂铁鎓阳离子与高氯酸根阴离子之间的离子缔合增强，从而在氧化时导致质量增加；然而，每摩尔电子的质量变化减小。从二茂铁羧酸盐偶联氨基十一烷基硫醇单层获得的结果被解释为是由于与FcCOO(CH2)11SH单层相比，具有规则间距的有序排列。
