Tunable Aryl Alkyl Ionic Liquids Research Articles

Synthesis, Toxicity, and Biodegradation of Tunable Aryl Alkyl Ionic Liquids (TAAILs)

TAAILs (Tunable Aryl Alkyl Ionic Liquids) are a new class of ionic liquids with an entirely new cationic substructure and a completely different charge distribution. They have a broad potential for applications, e.g., in metal extraction. In compliance with the basic principles of green chemistry, the optimization of the technological properties of chemicals should be investigated in parallel with the minimization of their (eco)toxicological hazard potential. In this study, we therefore synthesized and assessed the environmental effects of seven congeneric cations with different substitution patterns. In vitro assays with the isolated enzyme acetylcholinesterase and the cytotoxicity assay with IPC-81 cells were used, in conjunction with two in vivo tests using the marine bacteria Vibrio fischeri and the limnic green algae Scenedesmus vacuolatus, to assess the biological activity of these ionic liquids. Their biodegradability was tested using available procedures. Throughout this manuscript, special emphas...

Electronic Effects of para‐Substitution on the Melting Points of TAAILs

Owing to numerous new applications, the interest in "task-specific" ionic liquids increased significantly over the last decade. But, unfortunately, the imidazolium-based ionic liquids (by far the most frequently used cations) have serious limitations when it comes to modifications of their properties. The new generation of ionic liquids, called tunable aryl-alkyl ionic liquids (TAAILs), replaces one of the two alkyl chains on the imidazolium ring with an aryl ring which allows a large degree of functionalization. Inductive, mesomeric, and steric effects as well as potentially also π-π and π-π(+) interactions provide a wide range of possibilities to tune this new class of ILs. We investigated the influence of electron-withdrawing and -donating substituents at the para-position of the aryl ring (NO(2), Cl, Br, EtO(CO), H, Me, OEt, OMe) by studying the changes in the melting points of the corresponding bromide and bis(trifluoromethanesulfonyl)imide, (N(Tf)(2)(-)), salts. In addition, we calculated (B3LYP/6-311++G(d,p)) the different charge distributions of substituted 1-aryl-3-propyl-imidazolium cations to understand the experimentally observed effects. The results indicated that the presence of electron-donating and -withdrawing groups leads to strong polarization effects in the cations.

Tunable Aryl Alkyl Ionic Liquids (TAAILs): The Next Generation of Ionic Liquids

Tunable Aryl Alkyl Ionic Liquids (TAAILs): The Next Generation of Ionic Liquids