Organized 3D-alkyl imidazolium ionic liquids could be used to control the size of in situ generated ruthenium nanoparticles?

Abstract

The synthesis of ruthenium nanoparticles, RuNPs from the organometallic complex (η4-1,5-cyclooctadiene)(η6-1,3,5-cyclooctatriene)ruthenium(0), Ru(COD)(COT) in various imidazolium derived ionic liquids, ILs: [RMIm][NTf2] (R = CnH2n + 1 with n = 2; 4; 6; 8; 10), and [R2Im][NTf2] (RBu) and [BMMIm][NTf2] has been performed, under 0.4 MPa of H2, at 25 °C or at 0 °C with or without stirring. A relationship between the size of IL non-polar domains calculated by molecular dynamics simulation and the RuNP size measured by TEM has been found, suggesting that the phenomenon of crystal growth is probably controlled by the local concentration of Ru(COD)(COT) and consequently is limited to the size of the non-polar domains. Moreover, the rigid 3D organization based on C2–H⋯anion bonding and chosen experimental conditions, could explain the non-aggregation of RuNPs.