Two chain-based TbIII/DyIII complexes derived from m-nitrobenzoic acid with totally different structures and magnetic properties

Two Ln III complexes derived from one aromatic monocarboxylate ligand, namely [Tb 2 (mnba) 6 (H 2 O) 4 ] n ( 1 ) and [Dy 2 (mnba) 4 ( μ 3 -OH) 2 (H 2 O)] n ( 2 ) (Hmnba =  m -nitrobenzoic acid), have been prepared by similar synthetic procedures and structurally characterized. Complex 1 contains two identical one-dimensional (1D) chains with the syn,syn -carboxylate as linkers, while complex 2 takes the 1D chain structure with μ 3 - - OH and carboxylate as bridge. Magnetic studies indicate that ferromagnetic interactions between intra-chain metal centers exist in 1 and 2 and only complex 2 exhibits field-induced slow magnetic relaxation behavior.