Synthesis and structural analysis of heteronuclear hexacyanochromate(III) complex with tris(2-aminoethyl)amine), [Cd(tren)(Htren)][Cr(CN)6]⋅2H2O

Abstract The synthesized and structural investigation of a new heteronuclear hexacyanochromate complex based on amine containing tetradentate ligand tris(2-aminoethyl)amine ligand (tren) are reported. The complex have been characterized by spectral (FT-IR and Raman), elemental, thermal analysis (TG, DTG and DTA) as well as single crystal X-ray diffraction (SC-XRD) techniques. From elemental and spectral data, the formulae, [Cd(tren)(Htren)][Cr(CN)6]⋅2H2O (1), for the metal complex has been proposed. Single crystal X-ray diffraction (SC-XRD) measurements showed that the asymmetric unit of 1 consists of one Cd(II) ion, one Cr(III) ion, six cyanide ligands, one tren and one Htren ligands and two crystal water molecules. The structure of 1 presents one of tren ligands was protonated and the coordinated to Cd(II) ion as a monodentate ligand. Other tren ligand was also bonded to Cd(II) ion as a tridentate ligand to form a distorted trigonal-bipyramidal geometry. In the crystal structure, Cr(III) ion is coordinated by six carbon atoms from six different cyanide ligands, thus showing a distorted octahedral coordination geometry. In 1, The FT-IR and Raman spectral data of the complex compared with the crystallographic data, the results appear to be consistent with each other. Thermal properties of the title complex were investigated by thermogravimetric analysis (TG/DTG/DTA) in the temperature range of 30–700 °C in air atmosphere. Thermal studies confirmed the presence of water molecules in 1.