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Nuclear Magnetic Resonance Study of the Stoichiometry and Stability of Several Li + ‐Crown Ether Complexes in Various Acetonitrile‐Nitrobenzene Mixtures
Author(s) -
Karkhaneei Ebrahim,
Zebrajadian Mohammad Hasan,
Shamsipur Mojtaba
Publication year - 2001
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200100104
Subject(s) - chemistry , acetonitrile , nitrobenzene , crown ether , stoichiometry , lithium (medication) , solvent , stability constants of complexes , ether , inorganic chemistry , 15 crown 5 , solvation , 18 crown 6 , ion , organic chemistry , medicine , endocrinology , catalysis
Lithium‐7 NMR spectrometry was used to study the complexation reaction between lithium ions and several 12‐, 15‐ and 18‐membered crown ethers in a number of binary acetonitrile‐nitrobenzene mixtures. Formation constants of the resulting 1:1 complexes in different solvent mixtures were determined by computer fitting of the chemical shift‐mole ratio data. There is an inverse relationship between the complex stability and the amount of acetonitrile in the mixed solvent. Among different sized crown ethers used, 15‐crowns were found to form the most stable Li + complexes in the series. The influence of substitution on the macrocyclic rings on the stability of the resulting complexes is discussed.