Transition metal-directed assembly of diverse coordination polymers based on multifunctional ligand 2,4-dichloro-5-sulfamoylbenzoic acid

Abstract

Four new coordination polymers based on Co²⁺/Cd²⁺/Zn²⁺/Cu²⁺, Co(bpy)(H₂sba)₂(H₂O)₂ (1), Cd(bpy)(Hsba)H₂O (2), Zn(bpy)(Hsba) (3), [Cu₆(bpy)₅(H₂ssa)₆(H₂O)₂]·5H₂O (4), (bpy = 4,4′-bipyridine, H₃sba = 2,4-dichloro-5-sulfamoylbenzoic acid, H₄ssa = 4-chloro-5-sulphamoylsalicylic acid) have been successfully synthesized using the mild hydrothermal method with similar reaction conditions. X-ray diffraction analyses reveal that compound 1 exhibits a 1D linear chain formed by the linkage of Co centres and bpy ligands. Compound 2 shows a 2D window-shaped layer with 4⁴·6²sql topology. Compound 3 is a 3D framework containing a new topological prototype with a symbol of 6⁵·8. Compound 4 is characteristic of a 3D honeycomb lattice of hexagonal channels which are occupied by H₂ssa²⁻ ligands. Left- and right-handed helical chains with equal numbers in the framework are observed, which are constructed by repeating neutral trinuclear units of [Cu₃(H₂ssa)₃]. Worthy to mention here, when Cu²⁺ ions were introduced into the present reaction system, a new ligand H₂ssa²⁻ was obtained in situ by the hydrolysis of chlorine in H₃sba, which represents the first example of hydrolysis of chlorine either in coordination polymers and/or in hydrothermal synthesis. Moreover, the luminescent properties for compounds 2 and 3 as well as the H₃sba ligand, and the magnetic properties of compound 4 have been investigated in the solid state.