Two novel cyanido-bridged polymeric complexes with suspension bridge type connections and a series of related complex salts: crystallographic and thermal characterizations

Abstract

In this study, two cyanido-bridged coordination polymers and three cyanido complex salts with the general formulas [M(edbea)Ni(CN)₄] {M = Zn (1) and Cd (2); edbea = 2,2′-(ethylenedioxy)bis(ethylamine)} and [Cd(edbea)₂][M′(CN)₄]·XH₂O {M′ = Ni (3), Pd (4) and Pt (5); X = 2 (3) and 0 (4 and 5)} were synthesized and characterized using elemental analysis and FT-IR spectroscopy. X-ray studies of 1–5 exhibited two different coordination modes of the edbea ancillary ligand. While edbea acts as a suspension bridge with two nitrogen atoms positioned in an unusual way between adjacent metal ions for 1 and 2, in the remaining complexes, it behaves as a tetradentate ligand resulting in an eight coordinated Cd^II center. 3 showed an interesting packing of the cationic components hosted between the layers created by the anions and lattice water molecules. Thermal analysis studies showed that all of the complexes exhibited a similar mechanism in which the neutral groups were released first and then, the anionic ligands decomposed. Also, the complexes with salt structures could not retain their thermal stability as long as the polymeric ones.