A series of transition metal–azido extended complexes with various anionic and neutral co-ligands: synthesis, structure and their distinct magnetic behavior

Abstract

The crystal structures and magnetic properties of five new transition metal–azido complexes with two anionic [pyrazine-2-carboxylate (pyzc) and p-aminobenzoate (paba)] and two neutral [pyrazine (pyz) and pyridine (py)] coligands are reported. All five complexes were synthesized by solvothermal methods. The complex [Co₂(pyzc)₂(N₃)₂(H₂O)₂]_n (1) is 1D and exhibit canted antiferromagnetism, while the 3D complex [MnNa(pyzc)(N₃)₂(H₂O)₂]_n (2) has a complicated structure and is weakly ferromagnetic in nature. [Mn₂(paba)₂(N₃)₂(H₂O)₂]_n (3), is a 2D sheet and the Mn^II ions are found to be antiferromagnetically coupled. The isostructural 2D complexes [Cu₃(pyz)₂(N₃)₆]_n (4) and [Cu₃(py)₂(N₃)₆]_n (5) resemble remarkably in their magnetic properties exhibiting moderately strong ferromagnetism. Density functional theory calculations (B3LYP functional) have been performed to provide a qualitative theoretical interpretation of the overall magnetic behavior shown by these complexes.