N-Phenyliminodiacetic acid

The solution stabilities of the rare earth complexes with N-methyliminodiacetic acid, N-henzyliminodiacetic acid, N-phenyliminodiacetic acid, N-methoxyethyliminodiacetic acid, and N-methylmercaptoethyliminodiacetic acid have been measured at 25°C. and /x = 0.1 (KNOj). The linear relationship between the pk values for the ionization of the ammonium proton and the log Kj values for terdentate iminodiacetate ligands is demonstrated. This relationship is used to provide a measure of the free energy of formation of the third chelate ring in quadridentate iminodiacetates. 

Preparation of Ligands. The ligands used in this study were prepared by methods given in the literature N-methyliminodiacetic acid (4) N-benzyliminodiacetic acid (4) N-phenyliminodiacetic acid (7) ... 

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