One-Dimensional Coordination Polymers of MnII, CuII, and ZnII Supported by Carboxylate-Appended (2-Pyridyl)alkylamine Ligands - Structure and Magnetism

Four new complexes [Mn-II((LOO)-O-1)(H2O)][ClO4]center dot 2H(2)O (1), [Zn-II((LOO)-O-1)][ClO4]center dot 2H(2)O (2), [Cu-II((LOO)-O-3)][CF3SO3]center dot H2O (3), and [Zn-II((LOO)-O-3)][ClO4] (4) ((LOO-)-O-1 = 3-[2-(pyridine-2-yl)ethyl) {2-(pyridine-2-yl)methyl}amino]propionate; (LOO-)-O-3 = 3-[(2-(pyridine-2-yl)ethyl){(dimethylamino)ethyl}amino]propionate) have been synthesized and characterized by elemental analysis, IR, and UV/Vis spectroscopy. Structural analysis revealed that 1, 3, and 4 are one-dimensional chain-like coordination polymers. In 1 distorted octahedral MnN3O3 and in 3 square-pyramidal CuN3O2 coordination is satisfied by three nitrogen atoms and an appended carboxylate oxygen atom of the ligand, and an oxygen atom belonging to the carboxylate group of an adjacent molecule. In 4 trigonal bipyramidal ZnN3O2 coordination environment is provided by two nitrogen atoms and an appended carboxylate oxygen atom of the ligand in the equatorial plane, and the two axial positions are satisfied by a tertiary amine nitrogen and an oxygen atom belonging to the carboxylate group of an adjacent molecule. In 1 the Mn-II center is coordinated by an additional water molecule. In these complexes each monomeric unit is sequentially connected by syn-anti carboxylate bridges. Temperature-dependent magnetic susceptibilities for 1 and 3 are measured, revealing antiferromagnetic interactions through syn-anti carboxylate bridges between the M-II centers. Analysis of the crystal packing diagram reveals that in 1 extensive pi-pi stacking involving alternate pyridine rings of adjacent 1D chain exists, which eventually lead to the formation of a 2D network structure. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)