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A valence bond model for aqueous Cu(II) and Zn(II) ions in the AMOEBA polarizable force field
Author(s) -
Xiang Jin Yu,
Ponder Jay W.
Publication year - 2012
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.23190
Subject(s) - chemistry , aqueous solution , solvation , polarizability , valence (chemistry) , molecular dynamics , ion , metal ions in aqueous solution , computational chemistry , bond length , crystallography , molecule , crystal structure , organic chemistry
A general molecular mechanics (MM) model for treating aqueous Cu 2+ and Zn 2+ ions was developed based on valence bond (VB) theory and incorporated into the atomic multipole optimized energetics for biomolecular applications (AMOEBA) polarizable force field. Parameters were obtained by fitting MM energies to that computed by ab initio methods for gas‐phase tetra‐ and hexa‐aqua metal complexes. Molecular dynamics (MD) simulations using the proposed AMOEBA‐VB model were performed for each transition metal ion in aqueous solution, and solvent coordination was evaluated. Results show that the AMOEBA‐VB model generates the correct square‐planar geometry for gas‐phase tetra‐aqua Cu 2+ complex and improves the accuracy of MM model energetics for a number of ligation geometries when compared to quantum mechanical (QM) computations. On the other hand, both AMOEBA and AMOEBA‐VB generate results for Zn 2+ –water complexes in good agreement with QM calculations. Analyses of the MD trajectories revealed a six‐coordination first solvation shell for both Cu 2+ and Zn 2+ ions in aqueous solution, with ligation geometries falling in the range reported by previous studies. © 2012 Wiley Periodicals, Inc.