双甘肽稀土配合物溶液结构的^(13)C^1H NMR研究

^(13)C AND ~1H NMR STUDIES OF SOLUTION STRUCTURE OF LANTHANIDE COMPLEX WITH GLYCYL-GLYCINE

关于双甘肽的^(13)C化学位移行为及其与稀土离子的配位作用前人有过报导。但有关水溶液中双甘肽稀土配合物的结构仍不清楚。本文测定了在重稀土离子Dy^(3+)、Ho^(3+)、Er^(3+)、Tm^(3+)和Yb^(3+)作用下双甘肽^(13)C和~1H的顺磁诱导位移,研究了水溶液中双甘肽稀土配合物的组成及结构。1

^(13)C and ~1H NMR technique was used to study the interaction of Gly-Gly withheavy lanthanide cations Dy^(3+), Ho^(3+), Er^(3+), Tm^(3+) and Yb^(3+) in aqueous solution. Thestability constants for the 1: 1 and 1: 2 complexes of Gly-Gly with Ho^(3+) and Yb^(3+)were determined from the titration curves of chemical shift versus concentration ratioof lanthanide to Gly-Gly. The solution structure of the Ln-Gly-Gly complex wasanalyzed based upon the ^(13)C and ~1H lanthanide-induced shifts and the results showthat in the complex Gly-Gly is coordinated to the lanthanide ion through the carboxyloxygens with the backbone of the ligand in an extended state.