title: A novel hexanuclear mixed oxidation state Cu(II)(4)Cu(I)(2) cluster complex exhibiting weak ferromagnetic exchange.
abstract: The complex [(PAH)(4)Cu(II)(4)Cu(I)(2)Br(10)] (1) (PAH = picolinamide hydrazone) containing a Cu(II)(4)Cu(I)(2) hexanuclear cluster, with two well-separated Cu(II)(2) dinuclear centers, results from a redox reaction involving a hydrolytically unstable ligand, salicilyl picolinamide hydrazone, and CuBr(2) in aqueous acetonitrile. The Cu(II) centers are axially bridged via long bromine contacts, leading to ferromagnetic exchange (2J = 4.04 cm(-)(1)). Density functional calculations have been carried out, giving a comparable singlet-triplet splitting energy. 1 crystallizes in the triclinic system, space group Ponemacr;, with a = 9.253(3) A, b = 18.159(3) A, c = 7.199(5) A, alpha = 91.31(3) degrees, beta = 107.35(4) degrees, gamma = 104.22(2) degrees, and Z = 2.
authors.affiliation: Department of Chemistry, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X7, Canada.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Xu
authors.forename: Laurence K
authors.initials: LK
authors.lastname: Thompson
authors.forename: David O
authors.initials: DO
authors.lastname: Miller
authors.forename: Eliseo
authors.initials: E
authors.lastname: Ruiz
authors.forename: Santiago
authors.initials: S
authors.lastname: Alvarez