Figure 4.

All possible HB donor sites in [C₄MIM] cation to coordinate anions denoted as filled black circles with a white X. Different HB types are color coded and numbered as primary (1) with C(2) of imidazolium ring (black), ring (2) with C(4) and C(5) at rear part of imidazolium ring (red), first methylene (3a) or first methyl (3b) with C(6) or C(7) groups in alkyl chain (dark blue), secondary (4) with lateral methylene groups in alkyl chain (green), and terminal methyl (5) with terminal C(6) or C(10) methyl groups in alkyl chain (light blue). Reproduced with permission from ref (17). Copyright 2015 Royal Society of Chemistry.