2,2'-Ethylenebis(1,3-dithiane) as a polydentate μ 2 -, μ 4 - and μ 5 -assembling ligand for the construction of sulphur-rich Cu(I), Hg(II) and heterometallic Cu(I)/Hg(II) coordination polymers featuring uncommon network architectures

• Published in: Dalton transactions : an international journal of inorganic chemistry 2022-05, Vol.51 (19), p.7581-7606
• Main Authors: Viau, Lydie, Knorr, Michael, Knauer, Lena, Brieger, Lukas, Strohmann, Carsten
• Format: Article
• Language: English
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/D2DT00800A

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).