title: Theoretical characterization of end-on and side-on peroxide coordination in ligated Cu2O2 models.
abstract: The relative energetics of mu-eta1:eta1 (trans end-on) and mu-eta2:eta2 (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.
authors.affiliation: Department of Chemistry and Supercomputer Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Cramer
authors.forename: Armagan
authors.initials: A
authors.lastname: Kinal
authors.forename: Marta
authors.initials: M
authors.lastname: Włoch
authors.forename: Piotr
authors.initials: P
authors.lastname: Piecuch
authors.forename: Laura
authors.initials: L
authors.lastname: Gagliardi
mesh_terms: D002413:Cations, Divalent / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D007536:Isomerism; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure; D010087:Oxides / Q000737:chemistry; D010545:Peroxides / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry
chemical_list: D002413:Cations, Divalent; D010087:Oxides; D010545:Peroxides; D000644:Quaternary Ammonium Compounds; C470086:dihydrogen trioxide; D003300:Copper; C030973:cupric oxide