Sulphur ligand metal complexes. Part 6. Copper complexes of 2,5-dithiahexane and 3,6-dithiaoctane

Abstract

The dithioethers 2,4-dithiahexane (dth) and 3,6-dithiaoctane (dto) form the following complexes, some of which have been previously reported, with Cu^II and Cu^I: Cu(BF₄)₂L₂ and CuX₂L (L = dth or dto, X = Cl or Br); [CuL₂]X (L = dth or dto. X = SF,: L = dth, X = ClO₄); CuXL (L = dth, X = Cl, Br, or I; L = dto, X = I or SCN); and (CuCl)₂L (L = dto, X = Cl or Br). The complexes have been characterized by a variety of physicochemical techniques and where possible structures are proposed. The nature of the copper–sulphur bond is discussed and it is concluded that thioethers do not form appreciable π bonds with Cu^II. The chelated thioether ligand is readily displaced, e.g. from CuCl₂L (L = dth or dto) and CuCl(dth). by a variety of ligands (e.g. pyridine, pyrrolidine, 2,2′-bipyridyl,ethylenediamine, PPh₃, PMe₃S, and Na[S₂PMe₂]·2H₂O). With PPh₃ and CuCl(dth) the adduct CuCl(PPh₃)(dth) is formed.