2,2'-Ethylenebis(1,3-dithiane) as a polydentate μ-, μ- and μ-assembling ligand for the construction of sulphur-rich Cu(I), Hg(II) and heterometallic Cu(I)/Hg(II) coordination polymers featuring uncommon network architectures.

With the aim to elaborate novel and inexpensive sulphur-rich materials featuring unusual network architectures, the coordination chemistry of the tetradentate thiaheterocycle 1,2-di(1,3-dithian-2-yl)ethane L1 ligand toward CuX and HgX salts was investigated. When L1 is reacted with CuI in a 1 : 1 ratio, a two-dimensional CP [{Cu(μ-I)Cu}(μ-L1)] (CP1) is formed, in which two out of four S atoms of L1 remain non-coordinated. Upon treatment of L1 with CuI in a 1 : 2 ratio, [{Cu(μ-I)Cu}(μ-L1)] (CP2) is obtained, in which each S atom of L1 coordinates to one copper centre forming a 2D layer. Raising the ligand-to-CuI ratio to 1 : 4 affords the 2D material [{Cu(μ-I)(μ-I)Cu}(μ-L1)] (CP3), in which [Cu(μ-I)(μ-I)Cu] ribbons are interconnected through μ-bridging L1 ligands. Upon the reaction of L1 with CuBr in a 1 : 2 ratio, a 2D CP [{Cu(μ-Br)}(μ-L1)(μ-L1)] (CP4) is formed at room temperature and a 2D CP [{Cu(μ-Br)}(μ-L1)] (CP5) is obtained in refluxing propionitrile. In CP4 and CP5 Cu atoms are bridged by a single μ-Br ligand giving rise to [Cu(μ-Br)Cu] ribbons but CP4 differs from CP5 from the metal to ligand ratio and the presence of non-coordinated S atoms. Employing a 1 : 3 ratio, a 1D ribbon [{Cu(μ-Br)}(MeCN)(μ-L1)] (CP6) is generated, that contains both tetrahedral and trigonal copper atoms. CP6 also presents two different L1 ligands that differ by the coordination mode of the sulphur atoms (S acting as 2 or as 4 electron-donor). With CuCl, a 2D network [{Cu(μ-Cl)Cu}(μ-L1)] (CP7) is generated. L1 coordinates also on HgX salts to yield CPs whose architecture depends on the ligand-to-metal ratio. The meander-shaped 1D CP [(HgI)(μ-L1)] (CP8) and the linear 1D ribbons of CP9 and CP12 [(HgX)(μ-L1)] (X = Br, Cl) result from treatment with L1 in a 1 : 1 ratio. In the case of HgBr, using a 2 : 1 metal-to-ligand ratio, 1D polymeric [{BrHg(μ-Br)HgBr}(μ-L1)] (CP10) is produced. HgI and HgBr have also been reacted with 2-methyl-1,3-dithiane L2 yielding the molecular complexes [{IHg(μ-I)HgI}(κ-L2)] (D1) and [HgBr(κ-L2)] (M1). Two heterometallic 1D materials [{IHg(μ-I)HgI(μ-I){Cu(RCN)}(μ-L1)] (CP13) and (CP14) result from the treatment of CP1 with HgI in MeCN or EtCN. Performing the reaction of CP1 with HgBr in acetonitrile produces the zwitterionic 2D material [Cu(MeCN)}(HgIBr)(μ-L1)] (CP15).