Non-ionic Ln(III) chelates as MRI contrast agents: Synthesis, characterisation and 1H NMR relaxometric investigations of bis(benzylamide)diethylenetriaminepentaacetic acid Lu(III) and Gd(III) complexes

Paramagnetic liposomes containing amphiphilic bisamide derivatives of Gd-DTPA with aromatic side chain groups as possible contrast agents for magnetic resonance imaging

“…60 cm À1 to lower energy were observed for the carbonyl stretching frequencies upon complexation, indicating amide oxygen coordination to gadolinium(III) ion. These findings are consistent with previous studies which have shown that DTPA bisamide derivatives coordinate to lanthanide(III) ions via three acetate oxygens, three nitrogen atoms and two carbonyl oxygens of the amide group, while the ninth coordination site is occupied by a water molecule (Geraldes et al 1991;Ehnebom et al 1992;Bligh et al 1995;Aime et al 1997;Wang et al 1999).…”

Bis(phenylethylamide) Derivatives of Gd‐DTPA as Potential Receptor‐Specific MRI Contrast Agents

“…These findings are consistent with previous studies which have shown that DTPA-bis(amide) derivatives coordinate to trivalent lanthanide ions by three acetate oxygen atoms, three nitrogen atoms and two carbonyl oxygen atoms of the amide groups, while the ninth coordination site is occupied by a water molecule. [22][23][24][25] In the case of DTPA-(TA) 2 and DTPA-(HTA) 2 ligands, no evidence for the coordination of phenol oxygen to gadolinium(III) was observed. Positive-mode electrospray ionization mass spectroscopy (ESI-MS) of the Gd-DTPA-(TA) 2 , Gd-DTPA-(HTA) 2 and Gd-DTPA-(PAE) 2 complexes indicate the presence of fully complexed species in the solution (see Experimental Section and Scheme 1).…”

Potential MRI Contrast Agents Based on Micellar Incorporation of Amphiphilic Bis(alkylamide) Derivatives of [(Gd−DTPA)(H2O)]2−

“…These findings are consistent with previous studies, which have shown that DTPA bis(amide) derivatives coordinate to Ln III through three acetate oxygens, three nitrogen atoms and two carbonyl oxygens of the amide group, while the ninth coordination site is occupied by a water molecule. [9,10,14,16] The coordination polyhedron of the nine-coordinate lanthanide complexes can best be described as a tricapped trigonal prism, [33] with the bis-amide-DTPA ligand arranged around lanthanide ion in such a way that eight different enantiomers are possible. The eight possible enantiomers of the bound ligand give rise to the complex geometries, in which four are the mirror images of the other four.…”

“…[9,10,14,16] In solution, the presence of H 2 O molecule in the inner sphere was detected in the europium() complex by luminescence lifetime measurements [3,20] and for some dysprosium() complexes by 17 O NMR studies. [11] In attempt to achieve higher proton relaxivity, the Gd III complexes of (DTPA-bisamide) alkyl copolymers with alkyl chains containing six, ten, or twelve ϪCH 2 groups have been synthesized.…”