Copper(I) thiocyanate coordination polymers with dimethylpyrazine: synthesis, crystal structures, thermal and luminescence properties

摘要

The new copper(I) coordination polymers poly[(di-μ2-thiocyanato-N,s)-(μ_2-2,5-dimethylpyrazine-N,N)[ dicopper(I) and poly[diμ_2-thiocyanato-N,S)-(μ_2,3-dimethyl-pyrazine-N,N)] dicopper(I) (II) were prepared by the reaction of copper(I) thiocyanate with 2,3- and 2,5-dimethylpyrazine in acetonitrile. In all compounds different CuSCN sub-structures are found which are connected by the dimethylpyrazine ligands to multi-dimensional coordination networks. The thermal properties of all compounds were investigated using simultaneous differential thermoanalysis (DTA), thermogravimetry (TG) and mass spectrometry (MS) as well as temperature resolved X-ray powder diffraction. On heating, compound I and II lose all of the dimethylpyrazine ligands in an endothermic reaction and transform directly into copper(I) thiocyanate. Optical investigations show two excited states for both compounds in absorption and in luminescence measurements which are both, MC and LMCT in character.