Synthesis, Crystal Structures and Thermal Properties of the New Copper(I) Pseudohalide Coordination Polymers Catena[(μ2-thiocyanato-N,S)-(1- ethyl-2-methylpyrazine-N)]copper(I) and Poly[(di-μ2-tniocyanato-N, S)-(μ2-1-ethyl-2-methylpyrazine-N,N′)]dicopper(I)

Abstract

Reaction of copper(I) thiocyanate with 1-ethyl-2-methyl-pyrazine in acetonitrile yields the two new coordination polymers catena[(μ 2-thiocyanato-N,S)-(1-ethyl-2-methylpyrazine-N)] copper(I)(I) and poly[(di-μ2-thiocyanato-N,S)-(μ2-1-ethyl-2-methyl- pyrazine-N,N′)] di-copper(I) (II). The crystal structure of I is composed of CuSCN double chains in which each copper atom is connected to two thiocyanate anions and two 1-ethyl-2-methyl-pyrazine ligands. In this compound only one nitrogen atom of the 1-ethyl-2-methyl-pyrazine ligand is involved in copper coordination. The crystal structure of II is composed of CuSCN layers that are connected by the N-donor ligands via μ-N,N′ coordination into a three-dimensional coordination network. On heating the amine rich compound I loses half of the ligands and transforms into the amine-poorer compound II which occurs as an intermediate. Compound II decomposes on further heating to CuSCN. This reaction was investigated using simultaneous differential thermoanalysis and thermogravimetry coupled with mass spectroscopy and temperature dependent X-ray powder diffraction.