Synthesis, Crystal Structures, H₂S, and Iodine Uptake Properties of Four New Coordination Polymers Constructed from Group 12 Transition Metal Ions and a Bidentate Sulfur Donor Ligand

Abstract

In the current work, we have managed to design and synthesize a set of four new sulfur coordination polymers, namely, [ZnCl2(Ls)2] n (1), [CdCl2(Ls)2] n (2), [Cd­(NCS)­(μ2-SCN)2(Ls)2] n (3), and {[Hg­(μ2-Cl)­(Ls)2]­[ClO4]} n (4) using a branch tube method. They have been fully characterized using several techniques including elemental analysis, Fourier transform infrared spectroscopy, powder X-ray diffraction, photoluminescence spectroscopy, UV–vis, and single-crystal X-ray diffraction. Polymer 1 was synthesized directly by the reaction of zinc ions with the Ls ligand, while polymer 2, which is isostructural with 1, was synthesized by a single-crystal-to-single-crystal postsynthetic modification of polymer 1 where Zn­(II) ions were substituted by Cd­(II) ions. The effect of the anion on changing the topology has been carried out in polymer 3 using a thiocyanate anion in which SCN– groups were bonded to the metal centers in both terminal and bridging coordination fashions to form a two-dimensional network structure. The competition between halogen and uncoordinated perchlorate anions along with the Ls ligand constructed a cationic one-dimensional network structure in {[Hg­(μ2-Cl)­(Ls)2]­[ClO4]} n in which halogen atoms bridged between the metal centers and perchlorates counterbalanced the charge. The title polymers were considered as iodine and H2S adsorbents, and their kinetics were studied in detail. All polymers showed extreme stability toward both pollutants, and polymer 4 removed more than 99% of I2 from the solution. The presence of halogen and ClO4 – anions in polymer 4 was the key factor for its best removal efficiency in this group.

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

“…The coordination of metal to sulfur leads to a red‐shift in the position of this band that appears at 520 and 519 cm −1 for Zn and Hg‐SCP, respectively, which is the best indication for the formation of the sulfur coordination polymers. The very sharp band of υ (CN)–NCS and –SCN co‐ligands are observed at 2070 and 2089 cm −1 in the FT‐IR spectrum of zinc and mercury polymers [ 38 ] (Figure 1).…”

“…[34,35] Organic ligands with sulfur donor atoms especially heterocyclic thioamides, due to the fact that these ligands exhibit rich and diverse coordination chemistry that encompasses a great number of transition metal compounds, have been continuously attracting the attention of many researchers. [36][37][38][39][40][41][42][43][44][45] Among sulfur donor heterocyclic organic ligands, 1-methyl-3H-imidazole-2-thione [methimazole (MMI)] is an antithyroid medication that is considered the first-line agent for medical therapy of hyperthyroidism. Excessive production of thyroid hormones by the thyroid gland leads to a pathological condition named hyperthyroidism (overactive thyroid).…”

Selective adsorption of sulphur dioxide and hydrogen sulphide by metal–organic frameworks

“…27,28 In the literature, only a few theoretical and experimental studies on the H 2 S and SO 2 removal by MOFs have been published. [29][30][31][32][33][34] Most of them are recent. Indeed, experimental and computational efforts have been made recently to explore the use of MOFs 35 or natural or synthetic zeolites 36 for the effective removal of SO 2 and H 2 S gases.…”

“…In particular, they showed that UiO-66, ZIF-71, ZIF-69, and ZIF-97 exhibit good performances for H 2 S separation from air, with selectivity and adsorption capacities higher than 300 mg g −1 and 0.01 mmol g −1 at room temperature and atmospheric pressure, respectively. Besides, Beheshti et al 34 synthesized a set of four new sulphur coordination polymers ( e.g. [ZnCl 2 (L s ) 2 ] n polymer where the ligands L s = 1,1′-(pentane-1,5-diyl)bis(-3-methyl-1 H -imidazole-2-thione)).…”

New Hg(ii) coordination polymers based on a thioimidazole ligand with good performance to detoxify Hg(ii) and reversibly capture iodine

“…[44][45][46] On the other hand, despite the unique properties of sulfur based compounds in the capture of iodine, there are few investigations of iodine removal by sulfur based COFs, MOFs and CPs, so there is still a long way to go. [47][48][49][50] In light of these pieces of information and the exploration of our previous work on sulfur coordination polymers for the removal of iodine, in the current paper we have synthesized three novel Hg-CPs based on a sulfur containing Ls ligand [Ls = 1,1-bis(3-methyl-4-imidazoline-2-thione)methane]. Considering that the liver has the main function in detoxification in the human body, we have also studied the cytoprotective effects of the title ligand against mercury chloride toxicity using the MTT assay.…”