Syntheses, spectroscopic and thermal analyses of cyanide bridged heteronuclear polymeric complexes: [M(L)2Ni(CN)4]n (LN-methylethylenediamine or N-ethylethylenediamine; MNi(II), Cu(II), Zn(II) or Cd(II))

•New cyano-bridged heteronuclear polymeric complexes were synthesized.•The complexes are characterized by FT-IR and Raman spectra.•The Ni(II) ions are coordinated in square planar geometry.•The M(II) ions are coordinated in distorted octahedral arrangement.

Polymeric tetracyanonickelate(II) complexes of the type [M(L)2Ni(CN)4]n (LN-methylethylenediamine (men) or N-ethylethylenediamine (neen); MNi(II), Cu(II), Zn(II) or Cd(II)) have been prepared and characterized by FT-IR, Raman spectroscopy, thermal and elemental analysis techniques. Additionally, FT-IR and Raman spectral analyses of men and neen have experimentally and theoretically investigated in the range of 4000–250 cm−1. The corresponding vibration assignments of men and neen are performed by using B3LYP density functional theory (DFT) method together with 6–31 G(d) basis set. The spectral features of the complexes suggest that the coordination environment of the M(II) ions are surrounded by the two symmetry related men and neen ligands and the two symmetry related N atom of cyanide groups, whereas the Ni(II) atoms are coordinated with a square-planar to four C atoms of the cyanide groups. Polymeric structures of the complexes consist of one dimensional alternative chains of [M(L)2]2+ and [Ni(CN)4]2− moieties. The thermal decompositions in the temperature range 30–700 °C of the complexes were investigated in the static air atmosphere.

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