Formation of a Non-solvated Complex Anion

The following displacement reaction of the type [2] has been investigated for different donor solvents D  

The plot of the log Ksbcu-values versus DNsbCh of the respective donor moleculesi 26 D revealed the existence of the relationship  

Thus the qualitative prediction has been confirmed that the formation constant of the anionic complex formed by the addition of the competitive anionic ligand X will increase with decrease in the donor number of the solvent usedi 2,26 (Table 8 and Fig. 8). 

Propanediol-1,2-carbonate. . Phenylphosphonic difluoride Phenylphosphonic dichloride 

With a given formation constant of the anionic complex K3, strong donor properties of the solvent D will lead to low values of KsbCU- since the formation constant of the solvate complex Ki will be high. On the other hand high values for KsbCie are expected in a solvent of low DNsbcu- If is apparent that efforts must be made in order to estimate, in at least a semi quantitative way, the donor properties of a number of competitive ligands. 

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