%0 Journal Article %J The Journal of Physical Chemistry A %D 2006 %T Theoretical Characterization of End-on and Side-on Peroxide Coordination in Ligated Cu2O2 Models %A C.J. Cramer %A A. Kinal %A M. Wloch %A Piotr Piecuch %A L. Gagliardi %X

The relative energetics of μ-η1:η1 (trans end-on) and μ-η2:η2 (side-on) peroxo isomers of Cu2O2 fragments supported by 0, 2, 4, and 6 ammonia ligands have been computed with various density functional, coupled-cluster, and multiconfigurational protocols. There is substantial disagreement between the different levels for most cases, although completely renormalized coupled-cluster methods appear to offer the most reliable predictions. The significant biradical character of the end-on peroxo isomer proves problematic for the density functionals, while the demands on active space size and the need to account for interactions between different states in second-order perturbation theory prove challenging for the multireference treatments. In the latter case, it proved impossible to achieve any convincing convergence.

%B The Journal of Physical Chemistry A %V 110 %P 11557-11568 %8 09/15/2006 %G eng %N 40