Crystal structures and rotameric forms of some diarylsulphonyl-mono-, -di-, and -tri-selanes and their sulphur analogues

Abstract

The crystal structures of the compounds S₂(SO₂Ph)₂(1), Se₂(SO₂Ph)₂·½C₆H₆(2), S₂(SO₂C₆H₄Me-p)₂(3), Se₂(SO₂C₆H₄Me-p)₂(4), S(SO₂C₆H₄Me-p)₂(5), Se(SO₂C₆H₄Me-p)₂(6), S₃(SO₂C₆H₄Me-p)₂(7), and Se₃(SO₂C₆H₄Me-p)₂(8) have been determined by X-ray methods and refined to R 0.033–0.045 for 1 384–3 058 observed reflections. Crystals of (3) and (4) are isomorphous, as are those of (5) and (6), and (7) and (8). In (5)–(8) the molecules lie across crystallographic two-fold axes. In the disulphonyl-sulphane or -selane chains, the lengths of the terminal bonds are S–S 2.101(1)–2.141(1) and S–Se 2.242(1)–2.286(1)Å, and the lengths of the central bonds, between bivalent atoms, are S–S 1.987(1)–2.037 (1) and Se–Se 2.246(1)–2.304(1)Å. The rotameric forms, and reasons for variations in the lengths of bonds of the same type, are discussed. With three exceptions, the YXSC torsion angles (X,Y = S or Se) of 12 independent sulphonyl groups lie in the range 70–89, average 80°. In the S–SO₂R groups of the disulphonylsulphanes the S–S bond lengths correlate with the triple angle averages around the bonds.