Polynuclear Cu(II), Ni(II) and Cd(II) coordination compounds with bis(pyrimidin-2-yl)amine and dicyanamide

Abstract

In this study the synthesis, crystal structure and characterization of three new transition metal polynuclear compounds with formula [Cu(dipm)(μ-dca) 2] n (H 2O) ( 1), [Ni(dipm)(μ-dca) 2] n (C 2H 6O) 1/2 ( 2) and [Cd(dipm)(μ-dca) 2] n ( 3) (in which dipm = bis(pyrimidin-2-yl)amine and dca = dicyanamide) are reported. The isostructural compounds 1 and 2 contain a double-bridging end-to-end dca unit connecting two metal ions and a single bridging end-to-end dca unit between subsequent metals. Compound 3 exhibits only single bridging end-to-end dca units, oriented in three directions, giving rise to a 3D framework. The geometry around the Cu(II) ( 1) and the Ni(II) ( 2) centers is (distorted) octahedral and consists of two nitrogen atoms of a bis-chelating dipm ligand, two nitrogen atoms of two different dca anions both acting as end-to-end bridges between two M(II) ions and two nitrogen atoms of two different dca molecules which are end-to-end bridged to two different M(II) ions. The geometry around the Cd(II) ion ( 3) is octahedral and consists of 2 nitrogen atoms of a bis-chelating dipm ligand and four nitrogen atoms of four different dca anions which form end-to-end bridges to four different Cd(II) ions, thus producing a 3D network.