Ditopic thiacyclophanes containing the S(CH2)2X(CH2)2S (X = O, S) linkage. Synthesis and structures of 2,5,8,17,20,23-hexathia[9](1,2)[9](4,5)cyclophane and 5,20-dioxa-2,8,17,23-tetrathia[9](1,3)[9](4,6)-2,5-bis(ethoxy)cyclophane

Abstract

The Cs+/DMF mediated reactions of 1,2,4,5-tetra(bromomethyl)benzene and 1,2,4,5-tetra(bromomethyl)3,6-bis(ethoxy)benzene with dithiols HSCH2CH2XCH2CH2SH (X = S,O) were explored in order in order to ascertain the effect of structural variations on the regioselectivity of double ring-closure. Although a structure with bis(ortho) geometry was the target molecule, the major products are those with a bis(meta) structure. Two crystal structures, one with a bis(ortho) structure, 2,5,8,17,20,23-hexathia[9](1,2)[9](4,5)cyclophane, 1, and one with a bis(meta) structure, 5,20-dioxa-2,8,17,23-tetrathia[9](1,3)[9](4,6)−2,5-bis(ethoxy)cyclophane, 7, are reported. 1 crystallized in the triclinic space group [Formula: see text] with a = 8.583(3), b = 11.806(3), c = 5.448(2) Å, α = 97.18(2), β = 107.18(2), γ = 99.40(2)°, V = 511.6(6) Å3, and Z = 1. The structure refined to R = 6.48% and Rw = 7.13% for 1020 reflections with Fo2 > 3σ(Fo2). 7 crystallized in the triclinic space group [Formula: see text] with a = 9.568(2), b = 9.577(2), c = 8.312(2) Å, α = 113.53(2), β = 94.58(2), γ = 114.94(2)°, V = 604.3(7) Å3 and Z = 1. The structure refined to R = 3.86% and Rw = 4.20% for 1129 reflections with Fo2 > 3σ(Fo2). Both compounds sit on a crystallographic centre of symmetry and have the thioether linkages oriented on opposite sides of the central aromatic ring.