title: Copper(II) hexaaza macrocyclic binuclear complexes obtained from the reaction of their copper(I) derivates and molecular dioxygen.
abstract: Density functional theory (DFT) calculations have been carried out for a series of Cu(I) complexes bearing N-hexadentate macrocyclic dinucleating ligands and for their corresponding peroxo species (1c-8c) generated by their interaction with molecular O2. For complexes 1c-7c, it has been found that the side-on peroxodicopper(II) is the favored structure with regard to the bis(mu-oxo)dicopper(III). For those complexes, the singlet state has also been shown to be more stable than the triplet state. In the case of 8c, the most favored structure is the trans-1,2-peroxodicopper(II) because of the para substitution and the steric encumbrance produced by the methylation of the N atoms. Cu(II) complexes 4e, 5e, and 8e have been obtained by O2 oxidation of their corresponding Cu(I) complexes and structurally and magnetically characterized. X-ray single-crystal structures for those complexes have been solved, and they show three completely different types of Cu(II)2 structures: (a) For 4e, the Cu(II) centers are bridged by a phenolate group and an external hydroxide ligand. The phenolate group is generated from the evolution of 4c via intramolecular arene hydroxylation. (b) For 5e, the two Cu(II) centers are bridged by two hydroxide ligands. (c) For the 8e case, the Cu(II) centers are ligated to terminally bound hydroxide ligands, rare because of its tendency to bridge. The evolution of complexes 1c-8c toward their oxidized species has also been rationalized by DFT calculations based mainly on their structure and electrophilicity. The structural diversity of the oxidized species is also responsible for a variety of magnetic behavior: (a) strong antiferromagnetic (AF) coupling with J = -482.0 cm(-1) (g = 2.30; rho = 0.032; R = 5.6 x 10(-3)) for 4e; (b) AF coupling with J = -286.3 cm(-1) (g = 2.07; rho = 0.064; R = 2.6 x 10(-3)) for 5e; (c) an uncoupled Cu(II)2 complex for 8e.
authors.affiliation: Departament de Química and Institut de Química Computacional, Universitat de Girona, Campus de Montilivi, E-17071 Girona, Spain. miquel.costas@udg.es
authors.forename: Miquel
authors.initials: M
authors.lastname: Costas
authors.forename: Xavi
authors.initials: X
authors.lastname: Ribas
authors.forename: Albert
authors.initials: A
authors.lastname: Poater
authors.forename: Josep Maria
authors.initials: JM
authors.lastname: López Valbuena
authors.forename: Raül
authors.initials: R
authors.lastname: Xifra
authors.forename: Anna
authors.initials: A
authors.lastname: Company
authors.forename: Miquel
authors.initials: M
authors.lastname: Duran
authors.forename: Miquel
authors.initials: M
authors.lastname: Solà
authors.forename: Antoni
authors.initials: A
authors.lastname: Llobet
authors.forename: Montserrat
authors.initials: M
authors.lastname: Corbella
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Usón
authors.forename: José
authors.initials: J
authors.lastname: Mahía
authors.forename: Xavier
authors.initials: X
authors.lastname: Solans
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Shan
authors.forename: Jordi
authors.initials: J
authors.lastname: Benet-Buchholz