Synthesis, Characterization and Crystal Structure of a Novel Three-Dimensional Supramolecular Framework Containing Ni center dot center dot center dot pi Interaction Heteronuclear Complex: {[Cu(4(5)-Meim)(4)][Ni(CN)(4)] center dot A H2O}(n)

Abstract

The heteronuclear complex, {[Cu(4(5)-Meim)(4)][Ni(CN)(4)] center dot A H2O}(n) (1), (4(5)-Meim = 4(5)-methylimidazole) was synthesized and characterized by FT-IR spectroscopy, single crystal X-ray diffraction, thermal analysis and elemental analysis. The Cu(II) ion has a distorted square planar geometry, extended to (4 + 2) weak coordination by two nitrogen atoms of the cyano group. The coordination sphere around the Ni(II) ion should be described as a 4 + 2 geometry with the four cyano groups and the axial coordination site is located at the imidazole ring though a weak Ni center dot center dot center dot pi interaction. The coordination bond is much stronger than the Ni center dot center dot center dot pi interactions and it is expected that the formation of the coordination bond will affect more significantly the position of the absorption bands associated with the vibrations of the ligand. In addition, the out-of-plane modes of 4(5)-Meim are shifted to higher frequencies relative to free ligand. We propose that these shifts are indicative of the weak CHa (TM) a (TM) a (TM)pi and Nia (TM) a (TM) a (TM)pi interactions, according to the crystallographic and spectroscopic data.