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Supramolecular selective transport of Ca 2+ /Na + by dicarboxylic ligands across bulk liquid membranes
Author(s) -
Biancardi Alberto,
Marchelli Rosangela,
Dossena Arnaldo
Publication year - 1992
Publication title -
journal of molecular recognition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.401
H-Index - 79
eISSN - 1099-1352
pISSN - 0952-3499
DOI - 10.1002/jmr.300050404
Subject(s) - chemistry , selectivity , membrane , ligand (biochemistry) , supramolecular chemistry , ion transporter , ion , inorganic chemistry , stereochemistry , molecule , organic chemistry , receptor , biochemistry , catalysis
Bulk liquid membrane transport of Ca 2+ and Na + ions was performed with dicarboxylic type ligands containing ( S )‐phenylalanine (Phe‐2‐O) and ( S )‐benzyltyrosine (Bz‐Tyr‐2‐O) in pH gradients. With Bz‐Tyr‐2‐O, calcium was generally favoured at every pH, the transport rate strongly depending upon the ligand concentration. At pH 8, a reversal of selectivity (Na + /Ca 2+ ) was observed for the first time at low ligand concentration, thus suggesting that a supramolecular‐type of transport occurs as a consequence of the different assemblages formed by the ligand according to pH and concentration. This is the first case of M 2+ /M + selectivity induced by the carrier concentration.