Synthesis, Structure and Characterization of a New Transition Metal Complex: [Co0.5Ni0.5(C6H12N4)2(H2O)4]2 [Co0.5Ni0.5(H2O)6]2[SO4]4·13H2O

A novel complex, [Co 0.5 Ni 0.5 (C 6 H 12 N 4 ) 2 (H 2 O) 4 ] 2 [Co 0.5 Ni 0.5 (H 2 O) 6 ] 2 [SO 4 ] 4 ·13H 2 O, has been prepared and its hexagonal crystal was obtained from aqueous solution by solvent evaporation method. Single crystal X-ray diffraction revealed that the complex crystallizes in triclinic system, space group P−1 with lattice parameters a = 9.2268(7) Å, b = 13.3529(9) Å, c = 15.9211(11) Å and interfacial angles α = 66.246(3)°, β = 89.193(3)°, γ = 89.303(3)°. The coordination geometry around the metal ion is described as distorted octahedron in which the two hexamethylenetetramine molecules occupy two apical sites. TGA revealed three main mass loss steps at about 71 °C, 219 and 475 °C, which represents the temperature of dehydration, skeleton decomposition and sulfate decomposition, respectively. Further, the UV-VIS spectra showed an intense transmission around 293 nm and strong absorption in visible region, indicating the application potential as ultraviolet light filters (ULFs). Variable-temperature magnetic measurements were carried out for the complex, which was found to obey the Curie-Weiss law with C m = 8.475 cm 3 K mol −1 , θ = − 1.140 K. Graphical Abstract A new complex, [Co 0.5 Ni 0.5 (C 6 H 12 N 4 ) 2 (H 2 O) 4 ] 2 [Co0.5Ni0.5(H 2 O) 6 ] 2 [SO 4 ] 4 ·13H 2 O, has been introduced for its good optical feature of high transmission under 350 nm and strong absorption in visible region.