Phosphorus-31 contact shifts as a measure of weak ligand affinities. Interaction between alkali metal fluorenone radical anions and certain phosphorus(III or V) ligands
✍ Scribed by Constantinos G. Screttas; George A. Heropoulos; Barry R. Steele; Donald Bethell
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 199 KB
- Volume
- 36
- Category
- Article
- ISSN
- 0749-1581
No coin nor oath required. For personal study only.
✦ Synopsis
The nuclear magnetic resonance shifts, induced to 31P in and by d obs , P h 3 P, (MeO) 3 P (MeO) 3 PO alkali metal Ñuorenone radical anions in tetrahydrofuran solutions were measured. These parameters, which depend signiÐcantly on the cation for a given ligand, and also on the ligand for a given cation, were used to extract the corresponding 31P contact shifts,
The latter parameters are proposed as a measure of the ligand affinity d c (M). of a given phosphorus compound for a particular alkali metal. Trimethyl phosphate exhibits the greatest affinity for the lithium cation. The magnitudes of imply some covalency between the cation and the radical anion and d c (M) the "paradoxÏ of a heavier alkali metal such as potassium being covalently bonded to Ñuorenone radical anion has been explained. The transferability of the reported ligand affinities of Li, Naand K`is discussed.