Calculation of hydration enthalpies of aqueous transition metal cations using two coordination shells and central ion substitution

Density functional theory has been used to calculate hydration enthalpy for nine of the 10 fourth-period transition metal cation complexes with 6 and 18 water molecules. Two different approaches for calculation of solvation energy were compared. For the charges 2+ the difference between calculated and experimental enthalpy was −208 to −85 and −142 to −10 kJ/mol, for the charges 3+ the difference was −223 to −97 and −55 to 70 kJ/mol for complexes with 6 and 18 water molecules, respectively.