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(mu(2)-L)](n) (1) and [Hg (SCN)(2)(mu(2)-L)](n) (3). [Cd (NCS)Cl(mu(2)-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 I-2 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.