Synthesis,Characterization and Crystal Structure of a Polymeric Zinc(II) Complex Containing the Antimalarial Quinine as Ligand

Abstract A novel polymeric zinc(II) complex of quinine, [chlorosulphato (2-ethenyl)-4-azabicyclo[2.2.2]oct-5-ylium-(6-methoxyquinolin-4-yl) methanol zinc(II)] has been synthesized and characterized. Single-crystal X-ray diffraction analysis of the complex (C₂₀H₂₅ClN₂O₆SZn) revealed that quinine forms a zigzag coordination polymeric complex with Zn(II) of extended chains –ZnCl–O–SO₂–O–Zn–O–SO₂–O–ZnCl–. The crystals are monoclinic, space group C2 with a = 20.5035(5), b = 9.7943(2), c = 11.7814(4) ?, β = 96.578(2)°, Z = 4, V = 2350.3(1) ?³. The complex exhibits a tetrahedral geometry. Each Zn(II) centre is thus coordinated to an O atom from each of two sulphate bridges, a Cl atom and quinoline atom N(4) of the quinine moiety. The second quinuclidine nitrogen in the quinine is protonated. In the crystal, there is linkage of two polymeric chains related by a twofold rotation axis, resulting in a bilayer. The linking is achieved by hydrogen bonding from the quinine cation which provides two donors (–OH, N⁺–H), to oxygen atoms of sulphate groups which act as acceptors. Graphical Abstract The new polymeric zinc(II) complex of quinine, [chlorosulphato (2-ethenyl)-4-azabicyclo[2.2.2]oct-5-ylium-(6-methoxy quinolin-4-yl) methanol Zinc(II)] has been synthesized and structurally characterized The compound was characterized by IR spectroscopy, elemental analysis and X-ray diffraction. X-ray analysis showed that quinine forms a zigzag coordination polymeric complex with Zn(II) of extended chains –ZnCl–O–SO2–O–Zn–O–SO2–O–ZnCl–.