No abstract

Uma série de líquidos iônicos 1-alquil éter (e 1-alquil)-3-metilimidazólio 2-4 ([C x O y MIm] + [Ânion] ou [C x MIm] + [Ânion] , onde MIm = 3-metilimidazólio; C x O y = 1-alquil éter, C 7 O 3 = -(CH 2 ) 2 O(CH 2 ) 2 O(CH 2 ) 2 OCH 3 (A), C 3 O 1 = -(CH 2 ) 2 OCH 3 (B); C x = 1-alquil, C 10 = C 10 H 21 (C), C 4 = C 4 H 9 (D); e [Ânion] = H 3 CSO 3 (2), BF 4 (3) ou PF 6 (4)) foram preparados e caracterizados. A força da ligação de hidrogênio entre o cátion e o ânion dos líquidos iônicos 2-4 depende principalmente do ânion e diminui na ordem H 3 CSO 3 > BF 4 > PF 6 . Todos os líquidos iônicos metanosulfonatos 2 possuem uma forte desblindagem para o próton H 2 do ciclo imidazólio. Os líquidos iônicos funcionalizados com um grupo 1-alquil éter mostram densidades mais altas em comparação com seus equivalentes do grupo 1-alquil. Os sais 2a-b, 3a-d e 4a-b são líquidos iônicos à temperatura ambiente. E, todos os líquidos iônicos 1-alquil éter funcionalizados (exceto 4b) são completamente amorfos. As maiores faixas líquidas foram obtidas com os líquidos iônicos tetrafluoroborato devido as suas solidificações a temperaturas baixas e excelente estabilidade térmica. Estes dados fornecem informações importantes para o entendimento sobre possíveis aplicações e a preparação de líquidos iônicos com tarefas específicas.A set of 1-alkyl ether (and 1-alkyl)-3-methylimidazolium ionic liquids 2-4 ([C x O y MIm] + [Anion] or [C x MIm] + [Anion] , where MIm = 3-methylimidazolium; C x O y = 1-alkyl ether, C 7 O 3 = -(CH 2 ) 2 O(CH 2 ) 2 O(CH 2 ) 2 OCH 3 (A), C 3 O 1 = -(CH 2 ) 2 OCH 3 (B); C x = 1-alkyl, C 10 = C 10 H 21 (C), C 4 = C 4 H 9 (D); and [Anion] = H 3 CSO 3 (2), BF 4 (3) or PF 6 (4)) was prepared and characterized. The cation-anion hydrogen bonding strength showed to be mainly anion dependent and decreased in the order H 3 CSO 3 > BF 4 > PF 6 . All methanesulfonate ionic liquids 2 possessed a strongly deshielded H 2 imidazolium ring proton. 1-Alkyl ether functionalized ionic liquids showed higher densities in comparison to their 1-alkyl equivalents. The salts 2a-b, 3a-d and 4a-b are room-temperature ionic liquids. All 1-alkyl ether functionalized ionic liquids (except 4b) are completely amorphous. The widest liquid ranges were obtained with the tetrafluoroborate ionic liquids due to their late solidification and excellent thermal stability. These data provide important information for the understanding of their application scope and the preparation of task-specific ionic liquids.Keywords: imidazolium ionic liquids, ether-functionalized, hydrogen bonding, physicochemical properties, task-specific IntroductionRoom-temperature ionic liquids (RTILs), ionic salts that melt at and below ambient temperature, typically comprise of an organic cation and an organic or inorganic anion. The class of imidazolium RTILs is used in a wide variety of applications due to their attractive physical and chemical properties, 1-3 which include: air and moisture stability, low flammability, thermal stability, a neglectable vapor pressure, bei...

The hexafluorophosphate anion of 1-alkyl-3-methylimidazolium ionic liquids is responsible for their poor water miscibility. Transformation of the hexafluorophosphate ionic liquids into water miscible liquids by structural modifications in the imidazolium cation could result in new applications. Improved water miscibilities were achieved with 1-alkyl ether-3-methylimidazolium hexafluorophosphate ionic liquids. Especially, ionic liquid 1-triethylene glycol monomethyl ether-3-methylimidazolium hexafluorophosphate 5 showed a strongly increased water miscibility range at 30 °C, which was further enhanced in the presence of ethanol as cosolvent. Besides, a complete water miscibility of 5 was observed at an elevated temperature of 50 °C. This knowledge may facilitate the predictive development of new task-specific ionic liquids.

No abstract

Candida species have great ability to colonize and form biofilms on medical devices, causing infections in human hosts. In this study, poly(l-lactide) films with different imidazolium salt (1-n-hexadecyl-3-methylimidazolium chloride (C16MImCl) and 1-n-hexadecyl-3-methylimidazolium methanesulfonate (C16MImMeS)) contents were prepared, using the solvent casting process. Poly(l-lactide)-imidazolium salt films were obtained with different surface morphologies (spherical and directional), and the presence of the imidazolium salt in the surface was confirmed. These films with different concentrations of the imidazolium salts C16MImCl and C16MImMeS presented antibiofilm activity against isolates of Candida tropicalis, Candida parapsilosis, and Candida albicans. The minor antibiofilm concentration assay enabled one to determine that an increasing imidazolium salt content promoted, in general, an increase in the inhibition percentage of biofilm formation. Scanning electron microscopy micrographs confirmed the effective prevention of biofilm formation on the imidazolium salt containing biomaterials. Lower concentrations of the imidazolium salts showed no cytotoxicity, and the poly(l-lactide)-imidazolium salt films presented good cell adhesion and proliferation percentages with human mesenchymal stem cells. Furthermore, no acute microscopic lesions were identified in the histopathological evaluation after contact between the films and pig ear skin. In combination with the good morphological, physicochemical, and mechanical properties, these poly(l-lactide)-based materials with imidazolium salt additives can be considered as promising biomaterials for use in the manufacturing of medical devices.