Tuning magnetic properties using targeted structural distortion: New additions to a family of Mn6 single-molecule magnets
摘要:
We report the synthesis and magnetic properties of three hexametallic Mn clusters: [Mn6O2(Et-sao)(6)(O2C-Naphth) (2)(EtOH)(4)(H2O)(2)] (1) (HO2C-Naphth = 1-naphthoic acid, Et-saoH(2) = 2-hydroxyphenylpropanone oxime), [Mn6O2(Et-sao)(6)(O2C-Anthra)(2)(EtOH)(4)(H2O)(2)] center dot 0.66EtOH center dot 0.33H(2)O (HO2C-Anthra = anthracene-- carboxylic acid) (2 center dot 0.66EtOH center dot 0.33H(2)O) and [Mn6O2(Et-sao)(6)(O2CPhC CH)(2)(EtOH)(4)(H2O)(2)] center dot 1.7EtOH center dot 0.3H(2)O (HO2CPhC CH = 4-ethynylbenzoic acid) (3 center dot 1.7EtOH center dot 0.3H(2)O). Clusters 1-3 exhibit ferromagnetic exchange between all six Mn-III centres resulting in S = 12 ground spin states. Ac magnetic susceptibility and single crystal micro-SQUID measurements on 1-3 confirm SMM behaviour with barriers to magnetisation reversal of 60.12 (1), 60.10 (2) and 66.79 (3) K. (c) 2008 Elsevier B. V. All rights reserved.