Strange behaviour of transport properties in novel metal thiocyanate based ionic liquids

In a previous paper some of us presented the structure and properties new family ionic liquids, ILs, with common cation, 1-butyl-3-methyl imidazolium (the popular [C4C1Im]+ or [BMIM]+) variety anions based in thiocyanate (SCN)−: one reference sample ten anionic metal complexes different valences: AlIII, MnII, FeIII, CrIII, NiII, HgII, ZnII, CoII CuI, resulting, respectively, [BMIM](SCN), [BMIM]3 Al(SCN)6, [BMIM]4 Mn(SCN)6, Fe(SCN)6, Cr(SCN)6, Ni(SCN)6, [BMIM]2 Hg(SCN)4, Zn(SCN)4, Co(SCN)4 Cu(SCN)4. this we show experimental measurements electrical conductivity these ILs broad temperature range (about 90 K). Viscosity has been measured for six compounds wide range. addition, diffusion coefficient both ions forming IL samples using NMR-Dosy technique. spite being very similar from chemical point view, they present transport property values. Thus, viscosity varies more than two orders magnitude among those highest compound Al lowest that Hg. Moreover, differences between values extend order ILs. These three will be related pairs, thus through Walden’s rule compare molar fluidity, while Kohlrausch’s law Nerst-Einstein equation are related. Also, fluidity inverse viscosity) compared by means Stokes-Einstein relationship. calculate Laity interionic friction coefficients Finally, theoretical model is suggested to explain all evidences reported.