title: Sulfone-linked paracyclophanes via macrocyclic aromatic thioethers: synthetic and structural investigations.
abstract: Reaction of 4,4'-sulfonylbis(benzenethiol) with 4,4'-dichlorodiphenylsulfone under pseudo-high-dilution conditions leads to macrocyclic thioethersulfones [-S-Ar-SO2-Ar-]n (Ar = 1,4-phenylene). These include a highly strained [1+1] cyclodimer (n = 2), a cyclotrimer resulting from thioetherexchange reactions, and a [2+2] cyclotetramer which can adopt two entirely different conformations in the crystalline state, one having molecular D2d ("tennis-ball-seam") symmetry. The same type of reaction is successful using 4,4'-thiobis(benzenethiol) instead of 4,4'-sulfonylbis(benzenethiol) and affords macrocycles with a higher ratio of thioether to sulfone linkages. Exhaustive oxidation of macrocyclic thioethersulfones with hydrogen peroxide affords a series of sulfone-linked paracyclophanes, [-Ar-SO2-]4, [-Ar-SO2-]6, [-Ar-SO2-]8 and [-Ar-SO2-]12. Single crystal X-ray analysis reveals [Ar-SO2-]4 to be a near-perfect square box, whilst the cyclic hexamer [-Ar-SO2-]6 adopts a much more irregular conformation. and [-Ar-SO2-]8 displays a "double-box" structure clearly related to that of [Ar-SO2-]4.
authors.affiliation: Department of Chemistry, Imperial College, South Kensington, London, UK. djw@ic.ac.uk
authors.forename: I
authors.initials: I
authors.lastname: Baxter
authors.forename: A
authors.initials: A
authors.lastname: Ben-Haida
authors.forename: H M
authors.initials: HM
authors.lastname: Colquhoun
authors.forename: P
authors.initials: P
authors.lastname: Hodge
authors.forename: F H
authors.initials: FH
authors.lastname: Kohnke
authors.forename: D J
authors.initials: DJ
authors.lastname: Williams