Quantum-mechanics based molecular dynamics simulations were used to investigate mono-, di-, tri- and tetraamino Ni2+ complexes in water. The simulations show an enormous influence of heteroligands on the reactivity of the first solvation shell of the Ni2+ ion. Comparing 17O-NMR measurements of identical systems with our simulation results shows a 10(4) times higher mobility of water molecules in the first solvation shell obtained from QM/MM MD simulations strongly affecting biochemically important properties of Ni2+ in the aqueous environment in living organisms.