- PREPARATION OF COMPLEXING AGENTS AND METAL ION COMPLEXES IN AQUEOUS MEDIA
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The invention relates to methods of preparation for bis-amide complexing agents, as well as paramagnetic metal ion complexes that include such agents. To prepare these complexing agents, a reaction mixture is formed that includes a bis-anhydride, a nitrogen-containing compound, and an aqueous solvent system. The nitrogen-containing compound reacts with the bis-anhydride in the reaction mixture to form the bis-amide complexing agent. The molar ratio of water to the nitrogen containing compound in the reaction mixture is greater than 3:1, respectively. In addition, the molar ratio of the nitrogen-containing compound to the bis-anhydride in the reaction mixture is no greater than 2.5:1, respectively. In some embodiments, a base other than the nitrogen-containing compound may be included in the reaction mixture (e.g., to buffer the reaction mixture). In some embodiments, the bis-amide complexing agent may be contacted with a paramagnetic metal ion salt to form a paramagnetic metal ion complex of the invention.
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Page/Page column 24
(2010/11/29)
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