Abstract
Herein the strategy of deliberate assembly of stable soluble macrocyclic single-molecule magnets (SMMs), using appropriately chosen linkers to bridge the axial sites, as a controlled way of forming single-chain magnets (SCMs) is tested. First, the manganese(III) macrocyclic complex, [Mn III (L Pr)(NCS) 2 ] (1), of the monoanionic tetradentate equatorial-N4-donor macrocyclic (L Pr) − ligand (formed from [1 + 1] Schiff base condensation of 2,2′-iminobisbenzaldehyde and dipropylenetriamine) is shown to be an SMM. Then, the 1:1 reaction of SMM 1 with sodium terephthalate linkers in H 2 O/DMF is shown, by X-ray structure determination, to form dark red single crystals of the desired one-dimensional (1D) coordination polymer, [Mn III (L Pr)(tpa)] n ·nH 2 O· 0.5nDMF (2), of alternating dicationic macrocycles [Mn III (L Pr)] 2+ (from 1) linked by the bridging dianionic linkers [tpa] 2−. Despite having the desired structural features, magnetic measurements show that 2 is an SMM, not an SCM, as the coupling along the 1D coordination polymer is negligible (with Δ eff /k B = 13.7(5) K and τ 0 = 1.4(5) × 10 −7 s). Future attempts to use this strategy of linking macrocyclic SMMs together to access SCMs will clearly require the use of linkers that are able to more efficiently relay the magnetic information along the resulting chain.