Synthesis and structural characterization of nickel(II) complexes of 3,14-diethyl-2,6,13,17-tetraazatricyclo[14,4,01.18,07.12]docosane with inorganic salts

The square-planar complex [Ni(L3)]Cl2·2H2O (1) (L1 = 3,14-diethyl-2,6,13,17-tetraazatricyclo[14,4,01.18,07.12]docosane) with inorganic salts KNO3 and NaN3 yields the octahedral nickel(II) complexes [Ni(L3)(NO3)2] (2) and [Ni(L3)(N3)2] (3). The structures were characterized by X-ray crystallography, spectroscopic, thermogravimetry and cyclic voltammetry. The crystal structures of compounds 2 and 3 show that each nickel(II) centre has an elongated distorted octahedral geometry with the axial ligands. Electronic spectra and redox potentials of the complexes 2 and 3 reveal a high-spin octahedral environment, which is reflected by the nature of the axial ligands. The TGA behaviors of two compounds 2 and 3 are also significantly affected by the nature of the axial ligands.

Graphical abstractThe nickel(II) complexes [Ni(L3)(NO3)2] (2) and [Ni(L3)(N3)2] (3) were synthesized and structurally characterized. The crystal structure of the compounds 2 and 3 exhibits a high-spin octahedral geometry with the axial ligands.Figure optionsDownload full-size imageDownload as PowerPoint slide