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Lower Ligand Denticity Leading to Improved Thermodynamic and Kinetic Stability of the Gd 3+ Complex: The Strange Case of OBETA
Author(s) -
Baranyai Zsolt,
Botta Mauro,
Fekete Marianna,
Giovenzana Giovanni B.,
Negri Roberto,
Tei Lorenzo,
PlatasIglesias Carlos
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201200265
Subject(s) - ethylamine , ligand (biochemistry) , chemistry , lanthanide , denticity , chemical stability , kinetic energy , ether , crystallography , molecule , ethylene glycol , gadolinium , medicinal chemistry , ion , inorganic chemistry , stereochemistry , crystal structure , organic chemistry , biochemistry , physics , receptor , quantum mechanics
OBETA, OBETA, you bet : Thermodynamic and kinetic measurements show an apparent paradox. The stability of complexes of lanthanide trivalent ions is higher with the heptadentate ligand OBETA (ethylene glycol‐bis(2‐aminoethyl ether)‐ N , N , N′ , N′ ‐tetraacetic acid) than with its octadentate homologue EGTA (2,2′‐oxybis(ethylamine)‐ N , N , N′ , N′ ‐tetraacetic acid). The unusual properties of Gd(OBETA) − (see structure), combined with the presence of two fast exchanging coordinated water molecules, candidates this complex as an MRI contrast agent.