title: Lower ligand denticity leading to improved thermodynamic and kinetic stability of the Gd3+ complex: the strange case of OBETA.
abstract: 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.
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Debrecen, H-4010, Debrecen, Egyetem tér 1., Hungary.
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Baranyai
authors.forename: Mauro
authors.initials: M
authors.lastname: Botta
authors.forename: Marianna
authors.initials: M
authors.lastname: Fekete
authors.forename: Giovanni B
authors.initials: GB
authors.lastname: Giovenzana
authors.forename: Roberto
authors.initials: R
authors.lastname: Negri
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Tei
authors.forename: Carlos
authors.initials: C
authors.lastname: Platas-Iglesias
mesh_terms: D002614:Chelating Agents / Q000737:chemistry*; D003287:Contrast Media / Q000737:chemistry; D004533:Egtazic Acid / Q000031:analogs & derivatives* / Q000737:chemistry*; D005682:Gadolinium / Q000737:chemistry*; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008024:Ligands; D008279:Magnetic Resonance Imaging; D008968:Molecular Conformation; D015394:Molecular Structure; D013237:Stereoisomerism; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D002614:Chelating Agents; D003287:Contrast Media; D028581:Lanthanoid Series Elements; D008024:Ligands; D014867:Water; D004533:Egtazic Acid; D005682:Gadolinium