Properties of ionic liquids containing silver(I) or protic alkylethylenediamine cations with a bis(trifluoromethanesulfonyl)amide anion

Masayasu Iida; Sayaka Kawakami; Emi Syouno; Hua Er; Eiji Taguchi

doi:10.1016/j.jcis.2011.01.070

Properties of ionic liquids containing silver(I) or protic alkylethylenediamine cations with a bis(trifluoromethanesulfonyl)amide anion

J Colloid Interface Sci. 2011 Apr 15;356(2):630-8. doi: 10.1016/j.jcis.2011.01.070. Epub 2011 Jan 27.

Authors

Masayasu Iida¹, Sayaka Kawakami, Emi Syouno, Hua Er, Eiji Taguchi

Affiliation

¹ Division of Material Science, Graduate School of Humanities and Sciences, Nara Women's University, Nara, Japan. iida@cc.nara-wu.ac.jp

PMID: 21324468
DOI: 10.1016/j.jcis.2011.01.070

Abstract

Ionic liquids of an N-alkylethylenediamine-silver(I) complex cation (alkyl=hexyl, 2-ethylhexyl, and octyl) or a protic N-alkylethylenediaminium cation (alkyl=butyl, hexyl, 2-ethylhexyl, octyl, decyl, and dodecyl) with a bis(trifluoromethanesulfonyl)amide counter anion (Ag-ILs and PILs, respectively) were prepared and their physicochemical properties were investigated. The trend of solidification decreased in the order octyl≫hexyl>2-ethylhexyl for the Ag-ILs, and butyl>dodecyl>decyl>octyl>hexyl≫2-ethylhexyl for the PILs. The diffusion coefficients of the cations indicated stronger intermolecular interactions in PILs than in the Ag-ILs because of hydrogen-bonding networks, and it has been revealed that the intermolecular interactions increase in the order, hexyl<octyl<2-ethylhexyl for the Ag-ILs, and hexyl≈2-ethylhexyl<butyl≈octyl<decyl≈dodecyl for the PILs. The ionicity of the PILs was nearly independent (0.38-0.43) of the lengths of the alkyl chain. The octyl Ag-IL provided uniform silver(0) nanoparticles upon reaction with aqueous NaBH(4) solution, whereas the 2-ethylhexyl and hexyl complexes did not form silver(0) sols. This difference can be attributed to the ordering of the nanostructures in the Ag-ILs.