The reactions of the diacylhydrazine ligands N,N'-bisalicyl-2,6-pyridine dicarbohydrazide (H6sphz) and N,N'-bis(3-methoxysalicyl)-2,6-pyridine dicarbohydrazide (H6msphz) with various 3d metal salts, afforded a series of coordination clusters, namely, [MnIII 2MnII(sphz)(acac)2(CH3OH)4] (1, acac- = acetylacetone anions), [NiII 3(msphz)(Py)4] (2, Py = pyridine), [CuII 6(sphz)2(Py)4] (3) and [CuII 6(msphz)2(Py)4]·2DMF·2H2O (4). Cluster 1 and 2 are single ligand assembled quasi-linear trinuclear structures. Both 3 and 4 consist a pair of quasi-linear {Cu3} cores, which are linked together by two crossed ligands. The adjacent 3d metal ions in all trinuclear cores of 1-4 are bridged by N-N single bonds of ligands, which convey ferromagnetic (FM) interactions between 3d metal centers of 1, and antiferromagnetic (AFM) interactions between those of 2-4. In particular, the FM interactions and linear arrangement of mixed-valence Mn centers in 1 result in a large spin ground states value (S T) of 13/2, as well as single-molecule magnet (SMM) behavior of slow relaxation and hysteresis of magnetization.
This journal is © The Royal Society of Chemistry.