Design of novel copper(II) and zinc(II) coordination polymers based on the 4′-functionalized terpyridines

The reaction of 4′-substituted terpyridyl ligand of 4′-hydroxy-2,2′:6′,2″-terpyridine (tpyOH) with zinc(II) acetate resulted in the formation of [Zn(tpyO)(OCOCH3)] (1). Complex 1 forms a one-dimensional polymer via coordination through oxygen atom in which tpyO− acts as a tetra-dentate ligand to afford a highly distorted trigonal bipyramid ZnN3O2. The reaction of zinc(II) acetate with 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine (pytpy) yields the zinc(II) complex [Zn(pytpy)(OCOCH3)(OH)] (2). The penta-coordinated complex [Zn(pytpy)(OCOCH3)](PF6) (3) obtained during the reaction of 2 with NH4PF6, was characterized by X-ray crystallography. The crystal structure of 3 reveals that pytpy acts as a bridging ligand between two metal centers, involved in a highly distorted trigonal bipyramidal geometry ZnN4O to form a 1D directional coordination polymer. The reaction of copper(I) iodide with 4′-(4-tolyl)-2,2′:6′,2″-terpyridine (toltpy) affords the copper(II) complex [Cu(toltpy)I2] (4). Copper(II) acetate was reacted with 4′-substituted terpyridyl ligand of 4′-hydroxy-2,2′:6′,2″-terpyridine (tpyOH) to yield the complex [Cu(tpyOH)(OCOCH3)2] (5). The reaction of copper(II) acetate with 4′-(4-anisyl)-2,2′:6′,2″-terpyridine (atpy) and 4,4′-bipyridine in the presence of NH4PF6 led to the formation of the novel binuclear complex [Cu2(atpy)2(μ-4,4′-bpy)(OCOCH3)2](PF6)2 (6). Crystal structure determination of 6 indicates that there are two crystallographically independent molecules of compound 6 comprise the asymmetric unit. Two copper atoms are further connected by the 4,4′-bipyridine in each form of dinuclear complex, giving rise to a distorted square pyramidal coordination geometry for each of Cu(II) centers. The thermal behaviors of all complexes have been investigated.

We herein report the preparation, characterization and crystal structure determination of two Zn-based coordination polymer of penta-coordinated [Zn(tpyO)(OCOCH3)] and [Zn(pytpy)(OCOCH3)](PF6) linked by substituted terpyridyl ligand of 4′-hydroxy-2,2′:6′,2″-terpyridine (tpyOH) and 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine (pytpy) to form 1D polymers via 4′-oxo- or nitrogen substituents. In addition, the reaction of copper(II) acetate with 4′-(4-anisyl)-2,2′:6′,2″-terpyridine (atpy), 4,4′-bipyridine and NH4PF6 resulted in the formation of the novel binuclear complex [Cu2(atpy)2(μ-4,4′-bpy)(OCOCH3)2](PF6)2. Crystal structure determination of [Cu2(atpy)2(μ-4,4′-bpy)(OCOCH3)2](PF6)2 reveals that there are two crystallographically independent molecules of the compound comprise the asymmetric unit and each of them forms a binuclear complex. The thermal properties of five zinc(II) and copper(II) complexes were reported.Figure optionsDownload as PowerPoint slide