Mercury(II), silver(I) and gold(I) thioether crown chemistry: synthesis, electrochemistry and structures of [(HgBr2)2([24]aneS8)], [{Ag2([24]aneS8)(CF3SO3)2(MeCN)2}∞], [Ag2([28]aneS8)][NO3]2 and [Au2([28]aneS8)][PF6]2 ([24]aneS8 = 1,4,7,10,13,16,19,22-octathiacyclotetracosane; [28]aneS8 = 1,4,8,11,15,18,22,25-octathiacyclooctacosane)

Abstract

The complexes [(HgBr₂)₂([24]aneS₈)], [{Ag₂([24]aneS₈)(CF₃SO₃)₂(MeCN)₂}_∞] ([24]aneS₈ = 1,4,7,10,13,16,19,22-octathiacyclotetracosane), [Au₂([28]aneS₈)][PF₆]₂ and [Ag₂([28]aneS₈)][NO₃]₂ ([28]aneS₈ = 1,4,8,11,15,18,22,25-octathiacyclooctacosane) have been synthesized, characterised and their crystal structures determined. In [(HgBr₂)₂([24]aneS₈)] two HgBr₂ units are bound to the macrocycle forming a discrete binuclear complex, Hg(1)–Br(1) 2.511(2), Hg(1)–Br(2) 2.588(2), Hg(1)–S(4) 2.835(4), Hg(1)–S(7) 2.581(4) Å. In [{Ag₂([24]aneS₈)(CF₃SO₃)₂(MeCN)₂}_∞] infinite polymeric chains of [24]aneS₈ molecules and silver(I) ions are observed, Ag(1)–S(1) 2.5400(14), Ag(1)–S(4) 2.627(2), Ag(1)–S(7ⁱ) 2.556(2), Ag(1)–S(10ⁱ) = 2.5984(14) Å (i x, y + 1, z), with the large-ring crown acting as a bidentate ligand to two tetrahedral silver(I) centres. In contrast, [Ag₂([28]aneS₈)][NO₃]₂ is a binuclear complex with each Ag^I co-ordinated to four S-donors of the macrocyclic ligand, Ag(1)–S(1) 2.5257(12), Ag(1)–S(4) 2.6314(11), Ag(1)–S(8) 2.8932(12), Ag(1)–S(11) 2.4921(11) Å, and one NO₃^– completing a very distorted trigonal bipyramidal co-ordination sphere, Ag(1)–O(2) 2.759(3) Å. In [Au₂([28]aneS₈)][PF₆]₂ two gold(I) centres are complexed tetrahedrally within the octathiamacrocycle in a [2 + 2] manner, Au(1)–S(1) 2.330(2), Au(1)–S(4) 2.789(2), Au(1)–S(8) 2.763(2), Au(1)–S(11) 2.338(2) Å. The redox properties of the complexes are described.