Thermodynamic p K 1 and p K 2 values of 36 arylphosphonic acids have been determined. The p K values of the meta and para compounds are correlated well by the σ n parameter, suggesting that there is little conjugation between the phosphonic group and the aromatic ring; the ρ values of the first and second dissociations are 0.923 and 1.140, respectively. The- PO3H-group itself appears to be electron donating, contrary to earlier literature reports. ...
[Michaelis Justus Liebigs Annalen der Chemie, 1896 , vol. 293, p. 265 Full Text Show Details Michaelis; Paneck Justus Liebigs Annalen der Chemie, 1882 , vol. 212, p. 203]
