New complexes with 2-pyridyl ketone Schiff bases

Abstract

Seven new complexes of 2-pyridyl ketone Schiff bases N,N 0 -bis-(pyridin-2-yl-benziliden)-propan-1,3diamine (bpbpd) and N,N 0 -bis-[1-(pyridin-2-yl)-etiliden]propan-1,3-diamine (bpepd) with Co(II), Ni(II), Zn(II) and Cd(II) nitrates and perchlorates were synthesized and investigated using elemental analysis, spectroscopic techniques (IR and UV-Vis-NIR) as well as magnetic and conductometric measurements. The structure of a cadmium(II) complex was accomplished by single-crystal X-ray diffraction. The Schiff base ligands act as NNNN tetradentate ligands coordinating through pyridine nitrogens and azomethine nitrogens to transition metal ions. The metal ions are six-coordinate for Co(II) and Ni(II), fourcoordinate in the case of Zn(II) and eight-coordinate for Cd(II) ions. The coordination sphere of cobalt and nickel complexes is completed by two water molecules, resulting a distorted octahedron. In the case of zinc(II) complexes has been proposed a distorted tetrahedral geometry. The Cd(II) ions are surrounded by a tetradentate Schiff base ligand and two bidentate nitrate anions, leading to a dodecahedral coordination environment. Thermal decomposition of these compounds is a multistage process. Generally, water elimination occurs in the first step and the decomposition of nitrate groups and organic ligands in the next stages. The last step of decomposition for all complexes is strong exothermic and corresponds to oxidative combustion of the Schiff base ligand.

Azo dye with nitrogen donor sets of atoms and its metal complexes: Synthesis, characterization, DFT, biological, anticancer and Molecular docking studies

“…(Table ) and corresponding to one unpaired electron. The electronic spectrum of the Cu(II) complex gave a band at 17,985 cm −1 , suggesting the existence of a transition from d xy , d z2 and d xz , d yz transfer to the antibonding and half‐filled d x2‐y2 level which is consistent with an octahedral configuration . The Zn(II) and Cd(II) complexes are diamagnetic.…”

Coordinated metal complexes with curcumin Schiff base: Synthesis, investigation, antibacterial screening, antioxidant studies, molecular docking and density function theory calculations

“…Three bands at 568, 754, and 842 nm, which are attributed to transitions of 4 T 1g (F) → 4 T 1g (P) (ν 3 ), 4 T 1g (F) → 4 A 2g (F) (ν 2 ), and 4 T 1g (F) → 4 T 2g (F) (ν 1 ) in the octahedral cobalt(II) complex, respectively, were detected in the spectrum. The complexes of cadmium and zinc are diamagnetic and most probable for octahedral geometry 41 …”

“…The complexes of cadmium and zinc are diamagnetic and most probable for octahedral geometry. 41 The solid reflectance spectrum of the Fe(III)-complex exhibits one band at 21,455 cm À1 , which is attributable to the 6 A 1g ! T 2g (G) transition in the complex's octahedral geometry.…”