Synthesis of a bifunctional monophosphinic acid DOTA analogue ligand and its lanthanide(III) complexes. A gadolinium(III) complex endowed with an optimal water exchange rate for MRI applications.
A new bifunctional octa-coordinating ligand containing an aminobenzyl moiety, DO3APABn (H4DO3APABn = 1,4,7,10-tetraazacyclododecane-4,7,10-triacetic-1-{methyl[(4-aminophenyl)methyl]phosphinic acid}), has been synthesized. Its lanthanide(III) complexes contain one water molecule in the first coordination sphere. The high-resolution 1H and 31P spectra of [Eu(H2O) (DO3APABn)]- show that the twisted square-antiprismatic form of the complexes is more abundant in respect to the corresponding Eu(III)-DOTA complex. The 1H NMRD and variable-temperature 17O relaxation measurements of [Gd(H2O)(DO3APABn)]- show that the water residence time is short (298tauM = 16 ns) and falls into the optimal range predicted by theory for the attainment of high relaxivities once this complex would be endowed by a slow tumbling rate. The relaxivity (298r1 = 6.7 mM(-1) s(-1) at 10 MHz) is higher than expected as a consequence of a significant contribution from the second hydration sphere. These results prompt the use of [Gd(H2O)(DO3APABn)]- as a building block for the set-up of highly efficient macromolecular MRI contrast agents.
Rudovský
Jakub
J
Department of Inorganic Chemistry, Universita Karlova, Hlavova 2030, 128 40, Prague 2, Czech Republic.
Kotek
Jan
J
Hermann
Petr
P
Lukes
Ivan
I
Mainero
Valentina
V
Aime
Silvio
S
D005682:Gadolinium / Q000737:chemistry*; D006573:Heterocyclic Compounds, 1-Ring / Q000737:chemistry*; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008024:Ligands; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy / Q000379:methods / Q000592:standards; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D010103:Oxygen Isotopes; D010721:Phosphinic Acids / Q000138:chemical synthesis* / Q000737:chemistry; D011522:Protons; D012015:Reference Standards; D013696:Temperature; D014867:Water / Q000737:chemistry
D006573:Heterocyclic Compounds, 1-Ring; D028581:Lanthanoid Series Elements; D008024:Ligands; D009942:Organometallic Compounds; D010103:Oxygen Isotopes; D010721:Phosphinic Acids; D011522:Protons; D014867:Water; C071349:1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetic acid; D005682:Gadolinium