title: Synthetic, structural, spectroscopic and theoretical study of a Mn(III)-Cu(II) dimer containing a Jahn-Teller compressed Mn ion.
abstract: The heterobimetallic complex [Cu(II)Mn(III)(L)(2)(py)(4)](ClO(4))·EtOH (1) built using the pro-ligand 2,2'-biphenol (LH(2)), contains a rare example of a Jahn-Teller compressed Mn(III) centre. Dc magnetic susceptibility measurements on 1 reveal a strong antiferromagnetic exchange between the Cu(II) and Mn(III) ions mediated through the phenolate O-atoms (J = -33.4 cm(-1)), with magnetisation measurements at low temperatures and high fields suggesting significant anisotropy. Simulations of high-field and high frequency powder EPR data suggest a single-ion anisotropy D(Mn(III)) = +4.45 cm(-1). DFT calculations also yield an antiferromagnetic exchange for 1, though the magnitude is overestimated (J(DFT) = -71 cm(-1)). Calculations reveal that the antiferromagnetic interaction essentially stems from the Mn(d(x(2)-y(2)))-Cu(d(x(2)-y(2))) interaction. The computed single-ion anisotropy and cluster anisotropy also correlates well with experiment. A larger cluster anisotropy for the S = 3/2 state compared to the single-ion anisotropy of Mn(III) is rationalised on the basis of orbital mixing and various contributions that arise due to the spin-orbit interaction.
authors.affiliation: School of Chemistry, National University of Ireland, Galway, University Road, Galway, Ireland.
authors.forename: Nelly
authors.initials: N
authors.lastname: Berg
authors.forename: Thomas N
authors.initials: TN
authors.lastname: Hooper
authors.forename: Junjie
authors.initials: J
authors.lastname: Liu
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Beedle
authors.forename: Saurabh Kumar
authors.initials: SK
authors.lastname: Singh
authors.forename: Gopalan
authors.initials: G
authors.lastname: Rajaraman
authors.forename: Stergios
authors.initials: S
authors.lastname: Piligkos
authors.forename: Stephen
authors.initials: S
authors.lastname: Hill
authors.forename: Euan K
authors.initials: EK
authors.lastname: Brechin
authors.forename: Leigh F
authors.initials: LF
authors.lastname: Jones