A Mn(iii) single ion magnet with tridentate Schiff-base ligands

Abstract

Single ion magnet behaviour is reported for a mononuclear Mn(III) ion with tridentate Schiff-base ligands which exhibits a tetragonal Jahn–Teller elongation along the N_amine–Mn–N_amine axis and crystallises with two crystallographically distinct Mn(III) cations (unit A and unit B). While magnetic measurements show a large and negative axial zero-field splitting (D = −4.73 cm⁻¹), HF-EPR reveal two distinct large axial Ds (D = −4.60 cm⁻¹ for unit A and D = −4.18 cm⁻¹ for unit B), thus resulting in the largest D known to date for a Mn(III) single ion magnet. AC magnetic measurements at 2000 Oe allowed determination of the energy barrier for spin reversal (10.19 K) and spin reversal relaxation time (1.476 × 10⁻⁶ s) for the Mn(III) ion. Computational studies were used to characterise the electronic structure and substantiate the zero field splitting in the Mn(III) complex.