Syntheses, crystal structures, and magnetic properties of cyanido-bridged one- and two-dimensional Ln(III)-Fe(III) coordination polymers

Two new heterometallic coordination polymers, [Dy(TPA)Fe(CN6)(H2O)2]center dot 4H2O (1-Dy) and [Gd2(TPA)2Fe2 (CN6)2(CH3OH)2]center dot 8.5H2O (2-Gd) were synthesized by reacting DyCl3 center dot 6H2O with K3[Fe(CN)6] and tri[(2-pyridyl) methyl]amine (TPA). The structures of both complexes were established by single crystal X-ray diffraction. Polymer 1-Dy exhibits a one-dimensional (1D) chain structure formed by [Fe(CN)6]3- bridging the [Dy(TPA) (H2O)2]3+ units. For polymer 2-Gd, each [Fe(CN)6]3- unit is connected to three [Gd(TPA)(CH3OH)]3+ units through three nearly coplanar CN groups, forming a near-rectangular grid Gd2Fe2. These Gd2Fe2 extend to generate a 2-dimensional (2D) monolayered topology, which represents a cyclic formation of a novel grid structure. Hydrogen bonding interactions via water molecules stabilize both structures. Magnetic susceptibility measurements indicate weak antiferromagnetic interactions between Ln(III) and Fe(III) ions, with Fe(III) and Ln (III) centers behaving as nearly isolated magnetic entities.