Two N, N'-bis-(pyridin-4-yl)pyridine-2,6-dicarboxamide coordination compounds

Abstract

The molecular structures of tetra-aqua-[N,N'-bis-(pyridin-4-yl)pyridine-2,6-dicar-boxamide]-sulfatomanganese(II) dihydrate, [Mn(SO₄)(C₁₇H₁₃N₅O₂)(H₂O)₄]·2H₂O or [Mn(H₂L¹)(SO₄)(H₂O)₄]·2H₂O, (I), and tetra-aqua-bis[N,N'-bis-(pyridin-4-yl)pyridine-2,6-dicar-boxamide]cadmium(II) sulfate tetra-hydrate, [Cd(C₁₇H₁₃N₅O₂)₂(H₂O)₄]SO₄·4H₂O or [Cd(H₂O)₄(H₂L¹)₂]·SO₄·4H₂O, (II), both contain a central metal atom in a distorted octa-hedral geometry coordinated equatorially by four oxygen atoms from water mol-ecules. In (I), the axial positions are occupied by a nitro-gen atom from H₂L¹ and an oxygen atom from the sulfate anion, whereas in (II), the axial positions contain two nitro-gen atoms from two different H₂L¹ ligands and the sulfate anion acts as the charge-balancing ion. π-π stacking between pyridine rings and a network of hydrogen bonds involving the water molecules and the sulfate anions play a crucial role in the mol-ecular self-assembly of the two structures.

Keywords: CdII complex; MnII complex; coordination compound; crystal structure; heterocyclic nitro­gen ligand.