Ion Pair Cooperative Binding of Potassium Salts by New Rhenium(I) Bipyridine Crown Ether Receptors
2001; American Chemical Society; Volume: 40; Issue: 12 Linguagem: Inglês
10.1021/ic001450v
ISSN1520-510X
AutoresLindsay H. Uppadine, James E. Redman, Simon W. Dent, Michael G. B. Drew, Paul D. Beer,
Tópico(s)Analytical Chemistry and Sensors
ResumoThe new rhenium(I) bipyridine crown ether receptors 1−4 have been prepared and their ion pair recognition properties examined. The crystal structure of [1·KCl]2·2H2O demonstrates that potassium is coordinated by benzo-18-crown-6 and chloride is hydrogen bonded to the amide groups. Receptor 3 extracts solid KCl and KOAc into chloroform via ion pair complexation. NMR and emission titration studies with receptors 1−4 and KCl/KOAc show that cobound potassium enhances anion binding strength by electrostatic and conformational effects. Significant cooperative interactions are observed between the anion and cation sites for host 4 in CH3CN. This molecule coordinates potassium to form a 1:1 intramolecular sandwich complex, which preorganizes the host for acetate binding.
Referência(s)