2D and 3D coordination polymers based on 2,2′-bipyrimidine and cyanide bridging ligands incorporating coordinated and guest ammonia molecules. Synthesis, crystal structures, magnetic properties and thermal analysis of {[Ni(CN)4]2[(Ni(NH3)2)2(bpym)]·2H2O}n and {[Cu2(CN)2(bpym)]·NH3}n

The coordination polymers {[Ni(CN)4]2[(Ni(NH3)2)2(bpym)]·2H2O}n1 and {[Cu2(CN)2(bpym)]·NH3}n2 have been prepared from the reactions of M(NO3)2·nH2O [Cu(II), n = 3 and M = Ni(II), n = 6] with NaCN and bpym (2,2′-bipyrimidine) in concentrated aqueous ammonia, respectively. The structure of 1 is made of bipyrimidine bridged centrosymmetric dinuclear [Ni(NH3)2(μ-bpym)Ni(NH3)2] fragments connected by four [Ni(CN)4]2− anions giving rise to a 2D framework. Layers, which adopt a stair-like conformation, are stacked with an ABAB… repeat pattern. Water molecules are located in the interlayer space and are involved in hydrogen bond interactions with the non-bridging cyanide groups of the [Ni(CN)4]2− a…