The widely used 12−6 Lennard-Jones (LJ) nonbonded metal ion models often fail to simultaneously reproduce the structural and thermodynamic properties of metal ion solvation, which restricts its applicability. Our newly developed 12−6−4 LJ-type nonbonded model that includes a 1/r4 term to incorporate charge-induced dipole interactions reproduces multiple experimental properties of highly charged metal ions. 1-3 Herein, we discuss the optimization of pairwise parameters for Cd2+, Ni2+, Fe2+, and Zn2+ binding ethylenediamine (en) to capture the detailed structural and mechanistic insights in the chelate effect.4 With these parameters we perform the first MD study exploring the structural details of chelate ring opening/closure. We find the water molecules in the first solvation shell of the metal ion are found to facilitate the chelate ring formation. The optimized parameters further simulate the formation of bis and tris(en) complexes representing the wide applicability of the model to simulate coordination chemistry and self- assembly processes.

Simulating the chelate effect

2019 Spring National Meeting

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