Isostructural Coordination Polymers of Zn(II) or Co(II) from Assembling of Cationic and Anionic Parts and Their Utilities

Two isostructural cobalt(II) and zinc(II) 1D-linear coordination polymers of 2-isonicotinoyl-N-tosylhydrazinecarboxamide (H₃itca) composed of assembled anionic and cationic parts in their respective chain were characterized. Their utility as adsorbent was investigated. The anionic portion of the coordination polymers composed of [M(Hitca)₂]^2- was bridged by the cationic part [M(H₂O)₄]²⁺ (M = Co²⁺ and Zn²⁺). The hydrolytically stable zinc coordination polymer was insoluble in water and had a lower molar conductance (23.5 S m² mol^–1) in water, whereas the cobalt coordination polymer was soluble in water and had a molar conductance of 100 S m² mol^–1 that corresponded to an ionic species, showing its dissociation in solution. It was also confirmed by mass spectrometry. The crystals of both coordination polymers belong to P₂/n, with crystallographic similarity index unity. The zinc coordination polymer had the ability to adsorb select cationic dyes methyl-violet and methylene-blue with absorption capacities of 53.00 and 52.25 mg/g, respectively. It selectively adsorbed methylene-blue or methyl-violet from the corresponding mixture of these two dyes in aqueous solution. On the other hand, the cobalt coordination polymer was not suitable for dye adsorption, but useful in the displacement of intercalated ethidium bromide from calf-thymus DNA effectively.