The effect of alkyl chain length in a series of novel N-alkyl-3-benzylimidazolium iodide salts

The crystal structures of a series of low-melting N-alkyl-2-methyl-3-benzylimidazolium iodide salts with a range of alkyl chain lengths, from n = 1 to 5 and including both n- and s-butyl chains, are reported for the first time. Thermal analysis shows that the methyl- and (s-)butyl substituted salts have significantly higher melting points than the rest of the series. Analysis of the crystal structures allows examination of the influence of the substituents on the different cation-anion and cation–cation interactions and thus the physical properties of the salts.