J. S. Alper, R. I. Gelb, M. H. Schwartz
Dec 1, 1991
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Influential Citations
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Journal
Journal of inclusion phenomena and molecular recognition in chemistry
Abstract
Complexation stoichiometries and formation constants of tri- and tetra-protonated forms of 1,4,8,12-tetraazacyclopentadecane with NO3−, Cl−, IO3− and SO42− ions are determined by pH potentiometric and13C NMR spectrometric measurements. Estimates of ΔH and ΔS are obtained from the values of the temperature dependent formation constants and acid dissociation constants. All four anions form only 1 : 1 complexes with the triprotonated amine species. NO3− and Cl− form 1 : 1 complexes only with the tetraprotonated amine, while IO3− and SO42− form both 1 : 1 and 2 : 1 complexes. The complexation behavior is interpreted in terms of solvation and internal hydrogen bonding interactions.