| Autor: |
T. Spoormaker, A. Sinnema, J. M. Van Der Toorn, Antonius P.G. Kieboom, H. van Bekkum |
| Rok vydání: |
1975 |
| Předmět: |
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| Zdroj: |
Recueil des Travaux Chimiques des Pays-Bas. 94:53-59 |
| ISSN: |
0165-0513 |
| DOI: |
10.1002/recl.19750940209 |
| Popis: |
Complexation of ten alditols with praseodymium(III) [isosteric with calcium(II)] as the model cation has been studied in aqueous solution by 1H-NMR. The paramagnetic praseodymium ion shifted the resonances downfield in a regular way and allowed the identification of all the signals and the determination of the coupling constants. The following configurational sequence of tridentate ligands (H-COH), with respect to complex formation with PrIII has been established: xylo > threo > arabino (lyxo) > glycerol > erythro, ribo. Two major effects appear to be operative: (i) secondary hydroxyl groups show better complexation than primary hydroxyl groups; (ii) gauche butane and 1,3-dihydroxyl repulsions introduced upon complexation cause a decrease of the complex stability. Conformational data of both the uncomplexed and the complexed state in aqueous solution have been obtained from the vicinal coupling constants. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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