Solution Equilibria in YbDOTMA, a Chiral Analogue of One of the Most Successful Contrast Agents for MRI, GdDOTA
✍ Scribed by Lorenzo Di Bari; Guido Pintacuda; Piero Salvadori
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 421 KB
- Volume
- 2000
- Category
- Article
- ISSN
- 1434-1948
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✦ Synopsis
The structure and the conformational equilibria in aqueous conformation of the macrocycle ring. No evidence is obtained of a reorientation of the methyl acetate substituents. The and methanolic solutions of YbDOTMA (DOTMA = (1R,4R,7R,10R)-α,αЈ,αЈЈ,αЈЈЈЈ-tetramethyl-1,4,7,10-tetraaza-protons switch between positions with the same geometrical factors, i.e. positions that would have the same cyclododecane-1,4,7,10-tetraacetic acid) are investigated and the dynamics studied by means of NMR methods. The pseudocontact shifts were it not for the different magnetic susceptibility anisotropies of the two species; steady-state presence of two isomeric forms in slow exchange is confirmed and quantitatively characterized by EXSY. The NOE spectra on the major form allow unequivocal assignment of the conformations of the two isomers. exchange peaks are assigned to the inversion of the of the dynamics in solution of DOTMA complexes has so [a] Centro di Studio del CNR per le Macromolecole ParkerЈs Eu-naphthylethyl amide. [12] Stereoordinate ed Otticamente Attive, These two structures actually correspond to two main in-