Structures and magnetic properties of MnIII4LnIII4aggregates with a “square-in-square” topologyThis paper is dedicated to the memory of Dr Ian J. Hewitt.Electronic supplementary information (ESI) available: X-ray powder diffraction spectra, field dependence of magnetization and ac susceptibility measurements. CCDC reference numbers 756232, 756233, 756234, 756235, 756236and 765670. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/b926899e

The structures and magnetic properties of a family of new octanuclear heterometallic 3d-4fcomplexes [MnIII4LnIII4(μ3-OH)4(μ2,η1-X)4(O2CBut)8(t-bdea)4]·solv, where X = N3−, Ln = Y (1), Eu (2), Gd (3), Tb (4), Dy (5), Ho (6); X = OCN−, Ln = Dy (7); X = NO3−, Ln = Gd (8), Tb (9), Dy (10), Ho (11), Er (12); solv = MeCN or toluene, are reported. The metal topology in the aggregates can be described as consisting of a “Ln4-square inscribed in a Mn4-square”. Complexes 1-7are prepared by the reactions of t-butyldiethanolamine (t-bdeaH2) with a preformed hexanuclear manganese pivalate complex [Mn6], the respective lanthanide salt and either NaN3or NaNCO, while 8-12are obtained from the direct reaction of Mn(OAc)2, Ln(NO3)3·xH2O and t-butyldiethanolamine. The magnetic properties of all the complexes were investigated using variable temperature magnetic susceptibility and magnetisation measurements. Similar magnetic behaviour was observed for compounds containing the same lanthanide, indicating that changing the bridging ligand X does not have a significant effect on the magnetic behaviour. The TbIIIand DyIIIcompounds 4, 5, 7, 9and 10all show frequency-dependent acsusceptibilities indicative of a slow relaxation of magnetisation and are therefore considered as Single-Molecule Magnets. [ABSTRACT FROM AUTHOR]