2D polymeric copper(I) complexes. Synthesis, X-ray structures and spectroscopic studies of [CuX(pyrazine)] n (X=NCS and N 3) complexes containing molecular and anionic rod ligands

Abstract

Two mixed ligand complexes of the type CuLX for X=NCS, 1 and N 3 2 and L=pyrazine have been synthesized and characterized by spectroscopic and crystallographic methods. The IR and electronic spectra of both complexes are given and discussed. In the monoclinic crystals of complex 1 each copper atom is coordinated by two nitrogen atoms from two μ( N,N)-pyrazine ligands [Cu–N(av)=2.011 Å] and one nitrogen atom and a sulfur atom from two μ( N,S)-thiocyanato ligands [Cu–N=2.112(7) and Cu–S=2.3037(14) Å] giving rise to a two-dimensional structure with the copper atom in a distorted tetrahedral environment. The structure of complex 2 is very close to 1 and contains μ(1,3)-azido ligands [Cu–N=2.149 Å] as well as μ(N,N)-pyrazine ligands [Cu–N=1.994 Å]. The azido ligands are symmetrical [N 1–N 2=N 2–N 3=1.191 (5) Å] and linear [<N–N–N=179.7°].