Crystal structure of catena-poly[(1,3,4-thiadiazolium-2-thiolato)lead(II) dichloride], Pb(C₂H₂N₂S₂)Cl₂

Abstract

Source of materialThe mixture of PbCl2 (1 mmol) and 1,3,4-thiadiazolium-2-thiolate (2 mmol) was stirred in 15 mL of water at room temperature. Then the pH was adjusted to 3with dilute hydrochloric acid. The reaction mixture was then heated on awater bath for 5hat 50 .°C , and then filtered. Colorless crystals were separated from the mother liquor after slow evaporation at room temperature for 2weeks. DiscussionRecently, lead compounds have been increasingly studied owing to their possible applications in different fields, such as ionexchange, non-linear optics and catalysis, especially in environmental protection [1][2][3]. The control of heavy-metal lead in industrial effluents is of crucial importance for environmental reasons. One of the most important features influencing the high performance for lead removal is the coordination behavior of Pb ion [4][5][6]. Lead(II) possesses al arge radius, av ariable stereochemical activity, and aflexible coordination, which provides unique opportunities for the construction of novel metal-organic frameworks (MOFs) [7]. Meanwhile, thiadiazoles have attracted increasing attention because of their potential applications in pharmaceutical, agricultural, industrial, coordination and polymer chemistry [8][9][10].In the title crystal structure, the asymmetric unit consists of one Pb 2+ cations, two Cl -ion, and one 1,3,4-thiadiazolium-2-thiolate ligand ( figure, top). The 1,3,4-thiadiazolium-2-thiolate adopts a zwitterionic form. Each Pb atom is eight-coordinated by three S atoms from three 1,3,4-thiadiazolium-2-thiolate ligands and five Cl -ions. The Pb···Cl and Pb···Sbond lengths are.310(2) Å,r espectively, being in the normal range observed for other complexes containing So rC ld onors [11,12]. The Cl -ion shows m2-bridging (Cl1) and m3-bridging (Cl2) coordination mode, and link the Pb 2+ cations into an onedimensional network, with the Pb···Pb distance of 4.6099(7) Å and 4.1116(8) Å,respectively. The Pb···Pb distance between adjacent chains is 5.7597(8) Å.The 1,3,4-thiadiazolium-2-thiolate ligand adopts m 3-bridging coordination mode, in which S2 atom connects three Pb 2+ cations between adjacent chains into atwodimensional network.