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

Two mixed ligand complexes of the type CuLX for X=NCS, 1 and N, 2 and L=pyr azine have been synthesized and characterized by spectroscopic and crystall ographic 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 mu(N,N)-pyrazine ligands [Cu-N( av)=2.011 Angstrom] and one nitrogen atom and a sulfur atom from two mu(N,S )-thiocyanato ligands [Cu-N=2.112(7) and Cu-S=2.3037(14) Angstrom] giving r ise to a two-dimensional structure with the copper atom in a distorted tetr ahedral environment. The structure of complex 2 is very close to 1 and cont ains mu(1,3)-azido ligands [Cu-N=2.149 Angstrom] as well as mu(N,N)-pyrazin e ligands [Cu-N=1.994 Angstrom]. The azido ligands are symmetrical [N-1-N-2 =N-2-N-3=1.191 (5) Angstrom] and linear [<N-N-N=179.7 degrees]. (C) 1999 El sevier Science Ltd. All rights reserved.