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Synthesis, alkali metal picrate extraction, and alkali metal cation binding selectivities of some new cage‐annulated polyoxamacrocyclic crown ethers
Author(s) -
Marchand Alan P.,
Huang Zilin,
Chen Zhibing,
Hariprakasha H. K.,
Namboothiri I. N. N.,
Brodbelt Jennifer S.,
Reyzer Michelle L.
Publication year - 2001
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570380618
Subject(s) - picrate , chemistry , alkali metal , extraction (chemistry) , inorganic chemistry , solvation , calixarene , metal , alkaline earth metal , molecule , organic chemistry , ion
Five new cage‐annulated crown ethers, i.e. , 4a, 4b, 6b, 11a, and 11b, have been synthesized and their respective alkali metal picrate extraction profiles along with that of a previously synthesized host molecule, 6a, have been obtained. These results are compared with the corresponding results obtained for electrospray ionization mass spectrometric (ESI‐MS) measurements of relative binding selectivities displayed by the same hosts toward a series of alkali metal chlorides. Among the crown‐5 hosts studied, 6a displays enhanced avidity toward complexation with K + picrate in liquid‐liquid extraction experiments. Among the three crown‐6 hosts, 4b proved to be the best alkali metal picrate extractant and displayed significant levels of avidity toward complexation with the larger alkali metal cations ( i.e. , K + , Rb + , and Cs + ). The trends in the picrate extraction and the ESI‐MS results obtained herein show several notable similarities and some differences. The similarities generally stem from size‐selective binding properties that are intrinsic to the different cavity sizes of the cage‐annulated macrocycles, whereas the differences reflect the important influence of solvation effects on the binding properties of the macrocycles.