A New Type of Two-Dimensional Metal Coordination Systems: Hydrothermal Synthesis and Properties of the First Oxalate−bpy Mixed-Ligand Framework [M(ox)(bpy)] (M = Fe(II), Co(II), Ni(II), Zn(II); ox = C2O42-; bpy = 4,4‘-bipyridine)

Abstract

A new family of two-dimensional metal coordination polymers with the general formula [M(ox)(bpy)] (M = Fe(II), Co(II), Ni(II), Zn(II); ox = C2O42-; bpy = 4,4‘-bipyridine) have been designed and synthesized via hydrothermal routes. Quantitative yields were obtained in all cases. The title compounds [Fe(ox)(bpy)] (I), [Co(ox)(bpy)] (II), [Ni(ox)(bpy)] (III), and [Zn(ox)(bpy)] (IV) represent the first coordination network structure constructed by bridging oxalate and 4,4‘-bpy mixed ligands. I−IV are isostructural and belong to the orthorhombic crystal system, space group Immm (No. 71). The noninterpenetrated structure contains octahedral metal centers coordinated by two oxalate and two bpy ligands to form a two-dimensional layered network. Within each layer, relatively large rectangular voids are formed by four adjacent metal centers and the ligands bonded to them. The approximate dimensions of these cavities are 4 × 7 × 10 A in the composite three-dimensional structures. Magnetic susceptibility and field-de...