Abstract
Electrospray ionization (ESI) was used in conjunction with quadrupole ion trap mass spectrometry to measure metal binding selectivities of bis-crowned clefts in methanol solution. Each of the three cleft compounds contained two 15-crown-5 rings separated by different quinoline spacers. Binding selectivities were compared qualitatively with previous extraction results obtained for three bis-crown clefts complexing with the alkali metals sodium, potassium and rubidium in aqueous solution. The bis-crowned cleft molecules were found to form 1:1 and 2:1 metal—cleft complexes, and, in a few cases where larger alkali metals were involved, two cleft molecules were able to form 2:2 metal–cleft complexes cooperatively. The binding selectivity is greatly affected by the size of the alkali metal and by the flexibility of the quinoline bridge, factors that influence the degree of electrostatic repulsion between the two crown ether rings. © 1998 John Wiley & Sons, Ltd.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call