Protic Ionic Liquids Based on BIS‐TRIS Carboxylates: Synthesis, Structural Characterization and Buffer Activity

Ionic liquids, which have their own buffer capacity, have been classified as Good's buffer ionic liquids (GB‐ILs). GB‐ILs have demonstrated their potential in biotechnology due to their biocompatibility and profitable self‐buffering properties. A number of new GB‐ILs based on BIS‐TRIS (bis(2‐hydroxyethyl)‐amino‐tris(hydroxymethyl)methane) carboxylates have been synthesized. IR, NMR (¹H, ¹³C) spectroscopy, and thermal analysis data confirming the formation of new BIS‐TRIS salts are presented. The crystal structure of three BIS‐TRIS salts with salicylate, hydrogen oxalate, and oxalate anions was determined by single‐crystal X‐ray diffraction. Screening of synthesized BIS‐TRIS carboxylates as buffers in ⁶⁸Ga‐radiolabeling reactions of the model chelator p‐SCN−Bn‐DOTA, which is prototype of DOTA‐modified (1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid) peptides, was carried out.