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 I 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 pentacoordinated 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)I-2] (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 [Cu-2(atPY)2(mu-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. (C) 2015 Elsevier Ltd. All rights reserved.