Toward Optimized High-Relaxivity MRI Agents:  The Effect of Ligand Basicity on the Thermodynamic Stability of Hexadentate Hydroxypyridonate/Catecholate Gadolinium(III) Complexes

  • 10.1021/ic026240s
  • Inorganic Chemistry
  • p 4930-4937, Volume 42, Issue 16,
  • journal-article
The thermodynamic stabilities of the Gd III complexes of five hexadentate ligands which incorporate catecholate and hydroxypyridonate subunits with a range of basicities have been determined. The most stable Gd III complex at a physiological pH of 7.4 was observed for a ligand of intermediate basicity. The stability of this complex is comparable to that of Gd III complexes that feature eight-coordinate ligands and are currently used as magnetic resonance imaging contrast agents in diagnostic medicine. The accompanying bar chart shows pGd (= −log [Gd III free ]; total concentrations:  [Gd III ] = 10 - 6 M, [L] = 10 - 5 M) for five hexadentate ligands which incorporate catecholate and hydroxypyridonate subunits at a physiological pH of 7.4. The basicity of the ligands increases in going from 1 to 5.

Review

Tweaks Necessary to Improve Yield

Summary:

This paper describes the synthesis of a new hydroxypyridinone applicable for MRI technology. The basicity was measured and related to the thermodynamic stability with Gd.

 

Reaction of interest:

Our interest was the formation of the ring 6- methyl...

Add Review