Explorer Synthetic , structural , spectroscopic and theoretical study of a Mn ( III ) - Cu ( II ) dimer containing a Jahn - Teller compressed Mn ion

and theoretical study of a Mn(III)-Cu(II) dimer containing a Jahn-Teller compressed Mn ion' Dalton Transactions, vol 42, no. 1, pp. 207-216. General rights Copyright for the publications made accessible via the Edinburgh Research Explorer is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policy The University of Edinburgh has made every reasonable effort to ensure that Edinburgh Research Explorer content complies with UK legislation. If you believe that the public display of this file breaches copyright please contact [email protected] providing details, and we will remove access to the work immediately and investigate your claim. 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.