Field-induced slow relaxation in a monometallic manganese(III) single-molecule magnet.

Gavin A Craig,Jonathan J Marbey,Stephen Hill,Simon Parsons,Mark Murrie,Olivier Roubeau

doi:10.1021/ic5024136

Abstract

High-field electron paramagnetic resonance spectroscopy shows that the structurally distorted Mn(III) ion in Na5[Mn(L-tart)2]·12H2O (1; L-tart = L-tartrate) has a significant negative axial zero-field splitting and a small rhombic anisotropy (∼1% of D). Alternating-current magnetic susceptibility measurements demonstrate that 1, which contains isolated Mn(III) centers, displays slow relaxation of its magnetization under an applied direct-current magnetic field.

Highlights

Of the 3d monometallic complexes, manganese(III) is perhaps underexplored, given its paramount contribution to the magnetic properties of Mn12ac
Inorganic Chemistry surrounded by two fully deprotonated, symmetry-equivalent Ltart ligands, each coordinating to the central metal through three O atoms (O12, O21, and O31), leading to an {MnO6} firstcoordination sphere
In the absence of an applied dc field, no frequency dependence was observed for the real component of the susceptibility, χM′, nor were any signals observed for the outof-phase component, χM′′ (Figure S8 in the SI), perhaps because of the small rhombic component allowing quantum tunneling (QTM), as indicated by the electron paramagnetic resonance (EPR) measurements

Summary

Introduction

Of the 3d monometallic complexes, manganese(III) is perhaps underexplored, given its paramount contribution to the magnetic properties of Mn12ac. To the best of our knowledge, only three examples exist to date of monometallic manganese(III) complexes that display slow relaxation of magnetization.[12] In all of them, the central metal ion is six-coordinate with a significant tetragonal elongation arising from the Jahn−Teller effect. In this Communication, we describe the static and dynamic magnetic properties of Na5[Mn(L-tart)2]· 12H2O (1; L-tart = L-tartrate),[13] finding it to be one of the few known examples of monometallic manganese(III) compounds that display field-induced slow magnetic relaxation.

Results

Conclusion