Biomedical subjects
Publications and source records attributed to Bang Sook Lee.
Asymmetric electrostatic interactions dependent on pH between the redox molecules and the terminal group on the top of the self-assembled monolayer (SAM) afford control of the electron transfer property of the SAM having the imidazole terminal group.
1,3-Dialkylimidazolium salts, known as one of the ionic liquids, are very attractive molecules because their physicochemical properties can easily be tuned by the variation of the alkyl appendages of the imidazolium cations and counteranions. In this paper we report that the self-assembled monolayers (SAMs) terminating in 1,3-dialkylimidazolium salts with various counteranions [except Fe(CN)6(3-)] on a gold substrate exhibited a selective electron-transfer toward redox-probe molecules: the electron transfer occurred in the presence of Fe(CN)6(3-) (anionic redox-probe molecule) but did not occur in the presence of Ru(NH3)6(3+) (cationic redox-probe molecule). The SAM having Fe(CN)6(3-) as an anion showed the electron-transfer toward Ru(NH3)6(3+), and the Ru3+/2+ redox-switchable SAM was generated by reversible anion exchange between Fe(CN)6(3-) and SCN (or OCN-).
Self-assembled monolayers presenting imidazolium ions at the tail ends (SAMIMs) having different counteranions have been prepared on Au, and the measurement of water contact angles of the surfaces proved to be an extremely valuable simple technique for quantifying the effects of counteranions on hydrophilicity and hydrophobicity of SAMIMs, which will be extrapolated to the water miscibility of the related ionic liquids.