Second Coordination Sphere Water Molecules and Relaxivity of Gadolinium(III) Complexes: Implications for MRI Contrast Agents

Step by Step Assembly of Polynuclear Lanthanide Complexes with a Phosphonated Bipyridine Ligand

“…Phosphonate functions also display a very versatile coordination chemistry, potentially acting as monodentate, bidentate, or bridging coordination units. Finally, phosphonated complexes often display important second-sphere interactions, particularly with water surroundings in aqueous media …”

Dynamic Quantum Sensing of Paramagnetic Species Using Nitrogen-Vacancy Centers in Diamond

“…44 The nonuniform packing of the ions at the interface would affect the exchange rate of water molecules in the outer coordination sphere which significantly affects the spin properties of Gd 3+ ions. [48][49][50][51] The effect is not observed with chelated Gd 3+ as evidenced by the titration data recorded for titrations of Gadobutrol (Figures 3c and 3d) which exhibits a linear concentration dependency of the normalized contrast throughout the entire concentration range studied. Differences in the absolute values of contrast between the chelated Gd 3+ and free Gd are also seen for concentrations above 0.1 M with Gadobutrol producing contrast greater than 1.04 compared to lower contrast observed for free Gd 3+ (1.02 to 1.04).…”

Amplifying the Sensitivity of Zinc(II) Responsive MRI Contrast Agents by Altering Water Exchange Rates

“…This likely reflects the presence of multiple coordination isomers in solution, perhaps one with q = 0 (60%) and one with q = 1 (40%). Complexes with q = 0 have been observed previously in a variety of phosphonate and phosphinate complexes . To confirm the q values measured from 17 O NMR, q was also evaluated by luminescence lifetime measurements on the corresponding Eu­(III) complexes.…”