Acidities of the Metal Aqua Ions. A DFT Study (pp. 97-104)
Authors: Michael G. B. Drew, Samik Nag, and Dipankar Datta
Abstract: The experimental pKa values for some 30 metal aqua ions are found to correlate linearly (coefficient of determination r2 = 0.941) with the gas phase enthalpy changes ˘Ho for reaction (i) calculated by Density Functional Theory with TZP basis set. It is
[M(H2O)n]Z+ + m H2O ⎯¨ [M(H2O)n+m-1(OH)](Z-1)+ + H+ (i)
concluded that in exceptional cases, some metal ions (e. g. Sn2+, Hg2+, Tl3+) undergo expansion of the coordination sphere upon deprotonation.