Urea-based receptors, containing electron-withdrawing chromogenic substituents, in a DMSO solution, in the presence of varying excess of fluoride, do not form H-bond complexes, but undergo stepwise deprotonation of the two N-H fragments, an event which is signaled by the development of vivid colors. Double deprotonation is also observed in the presence of hydroxide. Less basic anions (CH3COO-, H2PO4 -) induce deprotonation of only one N-H.
Why, on Interaction of Urea Based Receptors with Fluoride, Beautiful Colors Develop.
ESTEBAN GOMEZ, DAVID;FABBRIZZI, LUIGI;LICCHELLI, MAURIZIO
2005-01-01
Abstract
Urea-based receptors, containing electron-withdrawing chromogenic substituents, in a DMSO solution, in the presence of varying excess of fluoride, do not form H-bond complexes, but undergo stepwise deprotonation of the two N-H fragments, an event which is signaled by the development of vivid colors. Double deprotonation is also observed in the presence of hydroxide. Less basic anions (CH3COO-, H2PO4 -) induce deprotonation of only one N-H.File in questo prodotto:
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