Cationic self-assembled monolayers composed of gemini-structured dithiol on gold: A new concept for molecular recognition because of the distance between adsorption sites

Shinobu Yokokawa, Kaoru Tamada, Eisuke Ito, Masahiko Hara

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

Cationic self-assembled monolayers (SAMs) composed of quaternary ammonium (QA) sulfur derivatives have been synthesized to control the distance between charged headgroups on gold substrates. Two molecules bearing resembling molecular structures, "gemini"-structured didodecyl dithiol (HS-gQA-SH) and didodecyl disulfide (QA-SS-QA), were utilized in this study, and the formation and structure of the SAMs were characterized by surface plasmon resonance spectroscopy (SPR), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared-reflection adsorption spectroscopy (FTIR-RAS). In the HS-gQA-SH SAM, the orientation and distance between QA groups are specified by the covalent bonding with ethylene spacer, while those of the QA-SS-QA SAM are determined by the electric repulsion between charged headgroups, that is, QA groups in the QA-SS-QA SAM are more randomly located, being more distant than with those in the HS-gQA-SH SAM. We found that L-tartaric acid, a probe molecule with two carboxyl groups having the distance of an ethylene unit, exhibits a strong affinity on the HS-gQA-SH SAM. In contrast, no specific binding was observed on the QA-SS-QA SAM. These results imply the possibility to build up a molecular recognition system on surfaces because of the control of the distance between the charged headgroups by using the gemini-structured molecular design.

Original languageEnglish
Pages (from-to)3544-3551
Number of pages8
JournalJournal of Physical Chemistry B
Volume107
Issue number15
DOIs
Publication statusPublished - Apr 17 2003
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Surfaces, Coatings and Films
  • Physical and Theoretical Chemistry
  • Materials Chemistry

Fingerprint Dive into the research topics of 'Cationic self-assembled monolayers composed of gemini-structured dithiol on gold: A new concept for molecular recognition because of the distance between adsorption sites'. Together they form a unique fingerprint.

  • Cite this