The Synthesis and Crystal Structures of New One- and Two-Dimensional Fe(II) Coordination Polymers Using Imidazole Derivatives

We studied the synthesis and crystal structures of a new two-dimensional (2D) coordination polymer, {FeII(1-Ethyl-imidazole)2[NiII(CN)4]}n (1), and one-dimensional (1D) coordination polymers, {FeII(1-benzyl-imidazole)4[NiII(CN)4]}n (2) and {FeII(1-Allyl-imidazole)4[NiII(CN)4]}n (3). Compound 1 has a 2D sheet structure, which is a traditional Hofmann-like structure. In compound 1, an octahedral FeII ion is coordinated with the nitrogen atoms of the [NiII(CN)4] planar unit at equatorial positions and monodentate imidazole derivatives at axial positions. The layers construct a parallel stacking array. Compounds 2 and 3 have a 1D chain structure. In compounds 2 and 3, the FeIIN6 coordination environment is formed with four imidazole ligands and two [NiII(CN)4]2− metalloligands. In the [NiII(CN)4]2− unit, two CN substituents act as bidentate ligands that form infinite –Ni–C–N–Fe–N–C–Ni– chains. Herein, we discuss the systematic design of polymeric dimensionality.