Accueil > Publications > Recherche par années > Années 1990 > 1997

Toth, E ; Burai, L ; Brucher, E ; Merbach, AE

Tuning water-exchange rates on (carboxymethyl)iminobis(ethylenenitrilo)tetraacetate (dtpa)-type gadolinium(III) complexes

Journal of The Chemical Society-Dalton Transactions (9) 1587-1594

par Administrateur - publié le , mis à jour le

Abstract :

A variable-temperature and -pressure, multiple-field O-17 NMR study has been performed on the gadolinium(III) complexes of an ethoxybenzyl (L-1) and symmetric (L-2) and asymmetric (L-3) mono(methylamide) derivatives of (carboxymethyl)iminobis(ethylenenitrilo)tetraacetate (dtpa) in order to study water exchange and rotational dynamics. Electronic relaxation parameters were obtained from EPR measurements. The water-exchange rates on the [GdL2(H2O)](-) and [GdL3(H2O)](-) complexes [k(ex)(298) = (1.9 +/- 0.1) x 10(6) and (1.3 +/- 0.1) x 10(6) S-1] are smaller than observed for [Gd(dtpa)(H2O)](2-) ; that of the ethoxybenzyl derivative [GdL1(H2O)](-) is k(ex)(298) = (3.6 +/- 0.1) x 10(6) S-1.