S the halide salts are regarded as precursors for the preparation of ILCs observed by following metathesis as a result of envisaged LC properties. Actually, the alkylation with alkyl halides is effective and feasible to acquire the precursors salts, because the halides act as excellent leaving groups. Importantly, the metathesis resulting in [Tf2 N- ] as the counterion is essential to decrease the melting point with the salts and tension the structure to be able to observe ionic liquid crystalline phase behavior. In our preliminary metathesis experiments with various counterions like hexafluorophosphate, we did not detect in any case ionic liquid or liquid crystal behavior. We observed thermal degradation of the samples, and this observation lead us to exclude these different counterions from this study set. A doable explanation for the thermal instability could be connected to the coordinating capability in the anion: the decomposition temperature is following the order of Cl- [BF4 – ] [PF6 – ] [Tf2 N- ], which is inversely proportional towards the tendency to form a steady alkyl-X species. In addition, growing the anion size reduces the Coulombic attraction contributions to the lattice power in the crystal, which leads to reduced melting points and explains the selection in the bigger anion [Tf2 N- ] [22]. After the metathesis, the six salts 1d-f and 2d-f with [Tf2 N- ] because the counterion had been investigated by suggests of DSC. While the precursor salts, except of 2a, were identified as not mesomorphic, the DSC traces for all salts with [Tf2 N- ] because the counterion show relevant events on heating (endotherm) and cooling (exotherm) asAppl. Sci. 2021, 11,7 ofshown in the second heating and cooling cycle for all six salts in Figure 1. All salts possess, at least, three reversible transitions within the cooling and heating cycles. Concentrating on the cooling cycles, three relevant events are observed for each salt, whereby the second transition appears to become by far the most pronounced. Contemplating the temperatures of your second transition, they look to not shift drastically within each in the salt series 1d-f and 2d-f. The temperatures of your initially and third transition instead shift to higher temperatures for the longer alkyl chain within the series. Concentrating around the heating cycles, at least three transitions is often observed for all salts and some of the salts (1d, 1f, 2e, 2f) show an more transition at reduce temperatures. The second transition would be the most MNITMT Inhibitor pronounced and PF-06454589 custom synthesis doesn’t shift considerably in temperature inside the series. In contrast, the very first and third Appl. Sci. 2021, 11, x FOR PEER Evaluation 8 of 14 transition shifts to larger temperatures with the increasing alkyl chain inside the series. A modest hysteresis is visible for all salts comparing the cooling and heating transitions.Figure 1. Differential scanning calorimetry (DSC) recorded for 1d-f and 2d-f displaying second Figure 1. Differential scanning calorimetry (DSC) recorded for 1d-f and 2d-f displaying thethe seccooling and heating curves with ten min-1 under nitrogen atmosphere. Exothermic peaks point ond cooling and heating curves with 10 C min-1 beneath nitrogen atmosphere. Exothermic peaks upward. point upward.As these salts exhibit numerous transitions upon heating and cooling, is affordable to As these salts exhibit quite a few transitions upon heating and cooling, it it really is affordable assume that they show atat leastone liquid crystalline phase. As a result, the first transition to assume that they show least 1 liquid cr.