Towards macrocyclic ionic liquids: novel ammonium salts based on tetrasubstituted p-tert-butylthiacalix[4]arenes

• Published in: RSC advances Vol. 7; no. 3; pp. 1671 - 1686
• Main Authors: Padnya, Pavel L., Andreyko, Elena A., Gorbatova, Polina A., Parfenov, Viktor V., Rizvanov, Ildar Kh, Stoikov, Ivan I.
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 01-01-2017
• Subjects: Alanine; Aromatic compounds; Esters; Glycine; Ionic liquids; Ions; Macrocyclic compounds; Melting points; Melts; Nitrogen atoms; Phenyls; Phthalimides; Quaternary ammonium salts; Solvents
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c6ra24734b

Water-insoluble ionic liquids based on
p-tert
-butylthiacalix[4]arenes tetrasubstituted at the lower rim with amide and quaternary ammonium groups containing alkyl, phenyl, ester, phthalimide, glycine, alanine and glycylglycine groups in cone and 1,3-alternate conformations were synthesized. It was established that macrocycles containing quaternary ammonium fragments with alkyl, phenyl and ester groups at the nitrogen atom in cone conformation melt lower by 8–31 °C than 1,3-alternate stereoisomers. It was shown that the introduction of the bis(trifluoromethylsulfonyl)imide anion as a counterion in the structure of quaternary ammonium salts based on thiacalix[4]arenes led to a substantial decrease in the melting point of the above salts.