Anion and cation binding by a new indole/pyridine/amine-based ion-pair receptor

✍ Scribed by Kristin N. Skala; Katelyn G. Perkins; Amna Ali; Robert Kutlik; Addie M. Summitt; Satyanarayana Swamy-Mruthinti; Farooq A. Khan; Megumi Fujita

• Book ID: 104098427
• Publisher: Elsevier Science
• Year: 2010
• Tongue: French
• Weight: 581 KB
• Volume: 51
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/j.tetlet.2010.10.012

✦ Synopsis

A new ion-pair receptor bis(3-bromoindol-2-ylmethyl)(2-pyridylmethyl)amine (1) was synthesized and studied for its anion and cation binding behavior using ESI-MS and 1 H NMR spectroscopy. Among halides, 1 exhibits the strongest binding with Cl À to form a 1:1 adduct (K a = 1042 ± 21 in CD 3 CN). Among alkali metal ions, Li + and Na + showed the strongest binding in the formation of a 1ÁM + complex. The simultaneous binding of Cl À and Li + to 1 was confirmed by 1 H NMR titration of a 1:1 mixture of 1 and Cl À with LiPF 6 in 83:17 v/v mixture of CDCl 3 and DMSO-d 6 . DFT-optimized structures of 1ÁCl À , 1ÁLi + , and 1ÁLi + ÁCl À are consistent with the chemical shift changes observed in 1 H NMR studies.