Crystal structure of a cadmium sulfate coordination polymer based on the 3,6-bis(pyrimidin-2-yl)-1,4-dihydro-1,2,4,5-tetrazine ligand

Abstract

The polymeric title compound, poly[aquahemi[μ2-3,6-bis(pyrimidin-2-yl)-1,4-dihydro-1,2,4,5-tetrazine](μ3-sulfato)cadmium(II)], [Cd(SO4)(C10H8N8)0.5(H2O)] n , (I), represents an example of a three-dimensional coordination polymer resulting from the reaction of CdSO4·8/3H2O with 3,6-bis(pyrimidin-2-yl)-1,4-dihydro-1,2,4,5-tetrazine (H2bmtz, C10H8N8) under hydrothermal conditions. The CdII atom has a distorted octahedral coordination environment defined by two nitrogen atoms from one H2bmtz ligand, three oxygen atoms from three different sulfate anions, and one oxygen atom from a coordinating water molecule. The 1,4-dihydro-1,2,4,5-tetrazine ring of the H2bmtz ligand is located about an inversion center, with the NH group being equally disordered over two sites. The sulfate anion acts as a μ3-bridging ligand to connect three CdII atoms, resulting in the formation of [Cd(SO4)(H2O)] sheets propagating parallel to the bc plane. Adjacent sheets are interconnected across the H2bmtz ligands, which coordinate the CdII atoms in a bis-bidentate coordination mode, to form a three-dimensional framework structure. The framework is further stabilized by classical O—H...O hydrogen bonds involving the coordinating water molecules and the sulfate groups, and by N—H...O hydrogen bonds between the disordered tetrazine NH groups and sulfate oxygen atom, along with C—H...π and π–π stacking [centroid-to-centroid separation = 3.5954 (15) Å] interactions between parallel pyrimidine rings of the H2bmtz ligand.