Berg, Nelly2; Hooper, Thomas N.6; Liu, Junjie4; Beedle, Christopher C.4; Singh, Saurabh Kumar5; Rajaraman, Gopalan5; Piligkos, Stergios7; Hill, Stephen4; Brechin, Euan K.6; Jones, Leigh F.2
1 Administration, Department of Chemistry, Faculty of Science, Københavns Universitet2 National University of Ireland3 University of Edinburgh4 Florida State University5 Indian Institute of Technology6 University of Edinburgh7 Administration, Department of Chemistry, Faculty of Science, Københavns Universitet
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.