Structural Characterization of Novel Ionic Salts Incorporating Trihalide Anions

Abstract

The crystal structures of several low-melting salts containing trihalide ions, namely 1-ethyl-3-methylimidazolium tribromide ([C 2 mim][Br 3 ]), 1-ethyl-1-methylpyrrolidinium tribromide ([C 2 mpyr][Br 3 ]), and 1-propyl-1-methylpyrrolidinium triiodide ([C 3 mpyr][I 3 ]), are reported for the first time. Thermal analysis reveals that the tribromide salts are lower-melting than their monohalide analogues. Analysis of the crystal structures allows examination of the influence of the anions on the physical properties of the salts.

3-Methylpiperidinium ionic liquids

“…The mean CH•••Br distance is 2.96(6) Å, marginally shorter than the sum of van der Waals radii and, as in the case of chlorides discussed above, and in the range of those for related pyrrolidinium bromides. 59 Imidazolium chlorides 61,62 and bromides 59,62,63 show average contacts of 2.73(12) and 2.88(12) Å, respectively, although these figures are heavily weighted by very short contacts to the acidic C 2 H ring proton: the rest of the contacts are close to the distances for the piperidinium and pyrrolidinium systems already discussed (see Table 3). Therefore, imidazolium halides show distinguishably stronger hydrogen bonds to C 2 H, whereas in the structures of related piperidinium and pyrrolidinium analogues, a number of weak interionic hydrogen bonds dominate the structures.…”

“…i #EBUDOV, #EBUDUB, #JIRBUI, #JIRCAP, #JIRCAP01, #TAJDAK, #TAJDAK01, #TAJDAK02, #ZIBHUN, #ZIBHUN01, #ZIBHUN02 (refs. 59,62,63 ).…”

Halocyclization of 3-{[2-methyl(bromo)prop-2-en-1-yl]-sulfanyl}-5H-[1,2,4]triazino[5,6-b]indoles

“…The 1 H NMR spectra of 5 and 6 in that mixture are given below. (7). A solution of 0.609 g (2.4 mmol) of iodine in 3 mL of isopropyl alcohol was added to a solution of 0.300 g (1.2 mmol) of compound 3 in 5 mL of isopropyl alcohol, and the mixture was left to stand for 24 h at room temperature.…”

“…The Br 4 atom in the Br 3 anion is characterized by the largest deviation from the heterocycle plane (0.615 Å). The Br 2 -Br 3 and Br 3 -Br 4 bonds have different lengths (2.73 and 2.39 Å, respectively), which is sometimes observed for tribromide ions [6,7]. The reason is that the Br 2 atom is involved in short contacts with H 10 and N 10 of the cation.…”

The 3rd Australasian Symposium on Ionic Liquids (ASIL-3)

“…Dean et al [1] report the synthesis and crystal structure analysis of a series of novel ionic liquids utilizing trihalide anions. By studying a series of ionic liquids with systematic changes in either the cation or the anion the role of different interactions can be assessed.…”