Abstract
The reactions of the diacylhydrazine ligands N,N'-bisalicyl-2,6-pyridine dicarbohydrazide (H(6)sphz) and N,N'-bis(3-methoxysalicyl)-2,6-pyridine dicarbohydrazide (H(6)msphz) with various 3d metal salts, afforded a series of coordination clusters, namely, [Mn(III) (2)Mn(II)(sphz)(acac)(2)(CH(3)OH)(4)] (1, acac(-) = acetylacetone anions), [Ni(II) (3)(msphz)(Py)(4)] (2, Py = pyridine), [Cu(II) (6)(sphz)(2)(Py)(4)] (3) and [Cu(II) (6)(msphz)(2)(Py)(4)]·2DMF·2H(2)O (4). Cluster 1 and 2 are single ligand assembled quasi-linear trinuclear structures. Both 3 and 4 consist a pair of quasi-linear {Cu(3)} 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.