Hydration of copper(II): New insights from density functional theory and the COSMO solvation model

Vyacheslav S. Bryantsev, Mamadou S. Diallo, Adri C.T. Van Duin, William A. Goddard

Research output: Contribution to journalArticle

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Abstract

The hydrated structure of the Cu(II) ion has been a subject of ongoing debate in the literature. In this article, we use density functional theory (B3LYP) and the COSMO continuum solvent model to characterize the structure and stability of [Cu(H2O)n]2+ clusters as a function of coordination number (4, 5, and 6) and cluster size (n = 4-18). We find that the most thermodynamically favored Cu(II) complexes in the gas phase have a very open four-coordinate structure. They are formed from a stable square-planar [Cu(H2O)8]2+ core stabilized by an unpaired electron in the Cu(II) ion dx2-y2 orbital. This is consistent with cluster geometries suggested by recent mass-spectrometric experiments. In the aqueous phase, we find that the more compact five-coordinate square-pyramidal geometry is more stable than either the four-coordinate or six-coordinate clusters in agreement with recent combined EXAFS and XANES studies of aqueous solutions of Cu(II). However, a small energetic difference (∼1.4 kcal/mol) between the five- and six-coordinate models with two full hydration shells around the metal ion suggests that both forms may coexist in solution.

Original languageEnglish (US)
Pages (from-to)9104-9112
Number of pages9
JournalJournal of Physical Chemistry A
Volume112
Issue number38
DOIs
StatePublished - Sep 25 2008

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Solvation
Hydration
Density functional theory
solvation
hydration
Copper
Ions
density functional theory
copper
Geometry
Metal ions
Gases
Electrons
Experiments
geometry
coordination number
metal ions
ions
vapor phases
continuums

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry

Cite this

Bryantsev, Vyacheslav S. ; Diallo, Mamadou S. ; Van Duin, Adri C.T. ; Goddard, William A. / Hydration of copper(II) : New insights from density functional theory and the COSMO solvation model. In: Journal of Physical Chemistry A. 2008 ; Vol. 112, No. 38. pp. 9104-9112.
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Hydration of copper(II) : New insights from density functional theory and the COSMO solvation model. / Bryantsev, Vyacheslav S.; Diallo, Mamadou S.; Van Duin, Adri C.T.; Goddard, William A.

In: Journal of Physical Chemistry A, Vol. 112, No. 38, 25.09.2008, p. 9104-9112.

Research output: Contribution to journalArticle

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