Alkylpyridinium Tetrahalidometallate Ionic Liquids and Ionic Liquid Crystals: Insights into the Origin of Their Phase Behavior

Abstract

Six N-alkylpyridinium salts [C n Py] 2 [MCl 4 ] (n = 4 or 12 and M = Co, Cu, Zn) were synthesized, and their structure and thermal properties were studied. The [C 4 Py] 2 [MCl 4 ] compounds are monoclinic and crystallize in the space group P2 1 /n. The crystals of the longer chain analogues [C 12 Py] 2 [MCl 4 ] are triclinic and crystallize in the space group P1. Above the melting tem-[a]5640 perature, all compounds are ionic liquids (ILs). The derivatives with the longer C12 chain exhibit liquid crystallinity and the shorter chain compounds only show a melting transition. Consistent with single-crystal analysis, electron paramagnetic resonance spectroscopy suggests that the [CuCl 4 ] 2ions in the Cubased ILs have a distorted tetrahedral geometry.

The crystal structure ofN-butylpyridinium bis(μ2-dichlorido)-tetrachloridodicopper(II), C18H28N2Cu2Cl6

“…[5][6][7][8]. To a solution of N-butylpyridinium chloride (0.342 g, 2 mmol) in dry acetonitrile (6 mL) copper(II) chloride (0.34 g, 2 mmol) was added.…”

The Use of Liquids Ionic Fluids as Pharmaceutically Active Substances Helpful in Combating Nosocomial Infections Induced by Klebsiella Pneumoniae New Delhi Strain, Acinetobacter Baumannii and Enterococcus Species

“…The bactericidal and fungicidal activities of the compounds depend primarily on the structure of the cation, and in particular, on the length of the alkyl or alkoxymethyl substituents [ 56 ]. The antimicrobial activity starts when the alkyl chain contains eight and more carbon atoms [ 66 , 67 , 68 ].…”

“…Extending the chain with subsequent carbon atoms results in an increase in the activity between 12–18 carbon atoms, where the maximum activity is observed, and usually falling with an increase to 16 carbon atoms [ 66 , 67 , 68 ]. The change of anions for the same cations usually does not affect the biological activity.…”

“…The process of obtaining the alkyl chain in the TPA molecule is extremely important, as the MIC decreases for all Gram (+) cocci as the chain length increases. The MIC of TPA 22 for S. aureus is eight mg/L and 16 mg/L for E. faecium , while the MIC for TPA with a chain length of 24–27 is two mg/L for S. aureus and ranges from two up to eight mg/L for Enterococcus [ 66 , 80 , 99 ]. The presence of a counter ion in the molecule does not affect the antimicrobial activity.…”

“…* ILs, which belong to APIs, were identified. ** The inhibitory concentration is equivalent to the bactericidal concentration [ 38 , 50 , 51 , 66 , 69 , 80 , 86 , 89 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 103 ].…”