Cobalt and cadmium coordination polymers formed with the multimodal ligand 3,6-di-pyrazin-2-yl-(1,2,4,5)-tetrazine

Abstract

Two coordination polymers, [(CoCl2)3(dpztz)2]∞ and [Cd(NO3)2(dpztz)]∞, have been prepared using the multi-modal ligand 3,6-di-pyrazin-2-yl-(1,2,4,5)-tetrazine (dpztz). [(CoCl2)3(dpztz)2]∞ adopts a three-dimensional CdSO4-like framework structure in which two distinct Co(II) coordination environments are observed. Whilst both Co(II) centres are coordinated by two chloride ligands in a trans-arrangement, one Co(II) is coordinated by two chelating sites from two dpztz ligands and the other Co(II) cation is coordinated by four pyrazine donors from four separate dpztz ligands. The observation of two distinct metal environments in a coordination framework is unusual for systems employing multi-modal ligands. In contrast Cd(NO3)2(dpztz)]∞ adopts a one-dimensional chain structure in which each Cd(II) cation is coordinated exclusively by chelating dpztz sites, in addition to two bidentate nitrate anions.