Syntheses and structural characterization of three new silver(I) coordination polymers with 1-(2-pyrazinyl)piperazine ligands

Three novel supramolecules of the Ag(I) complexes of [Ag-4(pyapa)(4)(SO4)(2) center dot 6H(2)O(n), 1, {[Ag-2(pyapa)(2)][ClO4](2)}(n), 2 and {[Ag-2(pyapa)(2)(H2O)][NO3](2)}(n), 3, (pyapa = 1-(2-pyrazinyl)piperazine) have been prepared by self-assembly of Ag(l) salts with 1-(2-pyrazinyl)piperazine (pyapa) in MeOH/H2O system. The IR, TGA and elemental analysis have been recorded and all the complexes have been structurally characterized by X-ray crystallography confirming that complexes 1-3 are one-dimensional coordination polymers. The pyapa ligands in complexes 1-3 bind soft acid Ag(I) ions through the pyrazinyl and piperazinyl groups forming the 1-D polymeric chains. The anions SO42 in complexes 1 shows the disordered geometries and bridging the Ag(I) atoms, while the anions ClO4- and NO3- in complexes 2-3 are not coordinated to the Ag(I) atoms, and all of them play an important roles in linking cationic chains into 3-D supramolecular structures. Thermal gravimetric analyses (TGA) were carried out to investigate their thermal properties. (C) 2008 Elsevier Ltd. All rights reserved.