Eggers Paul K, Zareie Hadi M, Paddon-Row Michael N, Gooding J Justin
School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia.
Langmuir. 2009 Sep 15;25(18):11090-6. doi: 10.1021/la9012558.
Three different length rigid norbornylogous bridges with terminal ferrocene moieties were synthesized. Pure self-assembled monolayers (SAMs) of the norbornylogous bridges and SAMs with the bridges diluted using either hydroxyl-terminated or methyl-terminated diluents were formed for each length of norbornylogous bridge. The SAMs were imaged with scanning tunneling micrsocopy (STM) and the electrochemical properties were investigated. It was found that SAMs composed of only norbornylogous bridges were crystalline-like, while in mixed SAMs, where the norbornylogous bridge was diluted, the ferrocene stood above the surface of the diluent because of the rigidity of the norbornylogous bridges and were homogeneously distributed across the surface. Further, the rate of electron transfer of the norbornylogous bridges was observed to be similar to an alkanethiol-derived ferrocene whose construct was designed to be as close as possible to that of the norbornylogous bridge. Finally, the rate of electron transfer for the norbornylogous bridges in a diluted SAM was slower with a hydroxyl-terminated diluent than with a methyl-terminated diluent.
合成了三种不同长度且带有末端二茂铁基团的刚性降冰片基桥。针对每种长度的降冰片基桥，分别形成了降冰片基桥的纯自组装单分子层（SAMs）以及使用羟基封端或甲基封端稀释剂稀释桥的SAMs。用扫描隧道显微镜（STM）对SAMs进行成像，并研究其电化学性质。结果发现，仅由降冰片基桥组成的SAMs呈类晶体状，而在混合SAMs中，降冰片基桥被稀释，由于降冰片基桥的刚性，二茂铁位于稀释剂表面上方且在整个表面均匀分布。此外，观察到降冰片基桥的电子转移速率与一种烷硫醇衍生的二茂铁相似，该二茂铁的结构设计得尽可能与降冰片基桥的结构接近。最后，在稀释的SAMs中，使用羟基封端稀释剂时降冰片基桥的电子转移速率比使用甲基封端稀释剂时慢。
