1D slide-fastener-like coordination polymers of Mn(II) derived from pyrazine-2,3,5,6-tetracarboxylic acid

Two new 1D slide-fastener-like coordination polymers {[Mn2(pztc)(phen)2(H2O)2]·4H2O}n (1) and {[Mn2(pztc)(bpy)2(H2O)2]·2H2O}n (2) have been synthesized by the reactions of pyrazine-2,3,5,6-tetracarboxylic acid (pztcH4) and Mn(OAc)2·4H2O in the presence of 1,10-phenanthroline (phen) or 2,2′-bipyridine (bpy) under hydrothermal conditions and characterized by elemental analyses, FT-IR, TGA and X-ray diffraction. In complex 1 and 2, metal ions are bridged by pyrazine-2,3,5,6-tetracarboxylate, coordinating in a hexadentate manner, so forming 1D polymeric chains. The remaining coordination sites of the metal ions are occupied by one O atom of water molecule and two N atoms of the terminal ligand (phen or bpy). IR spectra and thermal analysis data are in agreement with the crystal structure.