Comparison of Cation Basicity Scales

It seems obvious that the nine MCA and nine MCB scales in this chapter are interdependent to some extent. A systematic exploration of the similarities and differences between two given scales requires 72 correlations (36 for basicity and 36 for affinity) to be performed. If two given scales are found to be not, or poorly, correlated, further statistical work is necessary to understand the chemistry underlying the differences, for example by splitting up the sample of bases into families. 

only MCB scales will be compared since MCA is related to MCB. Moreover, the correlation analysis will be limited to the comparison of alkali metals, the comparison of aluminium with alkali metals and with transition metals, and the comparison of ttansition metals. The results are summarized in Table 6.19. 

The comparison of alkali metals shows that NaCB is well correlated with LiCB. Such a good correlation indicates that the blend of interactions contributing to LiCB and NaCB is similar for the two alkali metals within the wide range of studied ligands. As expected, the similarity decreases on going from Na+ to K+. 

Caldin, E. and Gold, V. (eds) (1975) Proton-Transfer Reactions, Chapman and HaU, London. 

(1983) Protonic acidities and basicities in the gas phase and in solution substituent and solvent effects. Prog. Phys. Org. Chem., 14, 247-350. 

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