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Accueil > Publications > Recherche par années > Années 2000 > 2007

Laus, S ; Sitharaman, B ; Tóth, E ; Bolskar, RD ; Helm, LM ; Wilson, LJ ; Merbach, AE

Understanding paramagnetic relaxation phenomena in water-soluble gadofullerenes

Journal of Physical Chemistry C 111 (15) 5633-5639

par Administrateur - publié le

Abstract :

Water-soluble, endohedral gadofullerenes exhibit considerably higher relaxivities than clinically used Gd3+-chelates and are currently explored as potential magnetic resonance imaging (MRI) contrast agents. The relaxivities of Gd@C-60(OH)(x) (x approximate to 27) and Gd@C-60[C(COOHyNa1-y)(2)](10) were previously found to vary with pH because of pH-dependent aggregation. By relaxometric measurements, we proved that aggregation can be suppressed by salt addition (75-100 equiv of sodium phosphate). In the aim of better understanding paramagnetic relaxation mechanisms in water-soluble gadofullerenes, we recorded variable-temperature and multiple-field O-17 and H-1 relaxation rates for Gd@C-60(OH)(x) and Gd@C-60[C(COOHyNa1-y)(2)](10) in both aggregated and disaggregated state (monomers). In the aggregated solutions, the O-17 T-1 and T-2 values are very different.