Synthesis and structural characterization of new group 12 metal ions coordination polymers built on sulfur-based ligand and probing their high iodine adsorption efficiency in micro and bulk forms

In this work, we have prepared two new sulfur CPs with group 12 transition metals, namely, [Zn (NCS)Cl(μ2-L)]n (1) and [Hg (SCN)2(μ2-L)]n (3). [Cd (NCS)Cl(μ2-L)]n (2), which is isostructural with 1, was synthesized for a comparison from our published work. These compounds have been characterized by FT-IR, UV–Vis, powder X-ray diffraction (PXRD), elemental analysis (CHNS), scanning electron microscopy (Fe-SEM), TGA, BET, and single-crystal X-ray analysis for 1 and 3. In the structure of all polymers, the bbit ligand [L = bbit = 1,1-bis(3-methyl-4-imidazoline-2-thion)butane] is bridged between metal centers by the anti-anti-anti conformation to form an infinite 1D zigzag chain. The considered polymers were used for the removal of a substantial amount of I2 from cyclohexane solution. Despite the nonporous and low dimensional frameworks of title polymers, their maximum iodine adsorption capacities were notable and in order of 817.68, 906.48, and 911.08 mg/g for polymers 1–3, respectively, with an extraordinary stability toward iodine. The capacity of micro-sized structures was almost double as compared with their bulk ones.