Electrochemically grafted single molecule junctions exploiting a chemical protection strategy

详细信息    查看全文

• 作者：Jinghong Liang^a ; Robert E.G. Smith^b ; Andrea Vezzoli^b ; Liqiang Xie^a ; David C. Milan^b ; Ross Davidson^c ; Andrew Beeby^c ; Paul J. Low^d ; Simon J. Higgins^b ; Bingwei Mao^a ; ^{bwmao@xmu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Richard J. Nichols^b ; ^{nichols@liv.ac.uk" class="auth_mail" title="E-mail the corresponding author}
• 关键词：STM ; single molecule conductance ; diazonium grafting ; SHINERS ; Raman spectroscopy
• 刊名：Electrochimica Acta
• 出版年：2016
• 出版时间：1 December 2016
• 年：2016
• 卷：220
• 期：Complete
• 页码：436-443
• 全文大小：1512 K

文摘

Diazonium grafted oligo(phenylene ethynylene) (OPE) monolayers suitable for single molecule conductance studies have been prepared. The surface-bound OPE is prepared from the amino tolan, 4-(2-(4-(2-(triisopropylsilyl)ethynyl)phenyl)ethynyl)benzamine, which is converted to the diazonium derivative in situ, and subsequently attached to a gold substrate using conventional cathodic electrochemical grafting. Multilayer formation is avoided by the presence of the bulky triisopropylsilyl (TIPS) protected ethynyl group. After removal of the TIPS group by treatment with fluoride, the film, now bearing exposed terminal acetylene moieties, is further functionalised by reaction with 1-iodo-4-acetylthiobenzene using Sonogashira coupling chemistry, to create sites bearing a strongly aurophilic top-contacting group. The success of these surface reactions is confirmed using Raman spectroscopy (gap-mode and SHINERS, employing gold nanoparticles and SiO₂ coated gold nanoparticles, respectively). It is shown that such thiolate-modified, diazonium-grafted monolayers are suitable for STM-based molecular junction conductance measurements.