Crystal structure of catena-poly[[[(2-ethoxypyrazine-κN)copper(I)]-di-μ2-cyanido] [copper(I)-μ2-cyanido]]

Abstract

In the asymmetric unit of the title coordination compound, {[Cu(CN)(C4H3OC2H5N2)][Cu(CN)]} n, there are two Cu atoms with different coordination environments. One CuI ion is coordinated in a triangular coordination geometry by the N atom of the 2-ethoxypyrazine molecule and by two bridging cyanide ligands, equally disordered over two sites exchanging C and N atoms, thus forming polymeric chains parallel to the c axis. The other Cu atom is connected to two bridging cyanide groups disordered over two sites with an occupancy of 0.5 for each C and N atom, and forming an almost linear polymeric chain parallel to the b axis. In the crystal, the two types of chain, which are orthogonal to each other, are connected by cuprophilic Cu..Cu interactions [2.7958 (13) Å], forming two-dimensional metal-organic coordination layers parallel to the bc plane. The coordination framework is further stabilized by weak long-range (electrostatic type) C-H..π interactions between cyano groups and 2-ethoxypyrazine rings.