DITOPIC THIACYCLOPHANES CONTAINING THE S(CH2)(2)X(CH2)(2)S (X=O,S) LINKAGE - SYNTHESIS AND STRUCTURES OF 2,5,8,17,20,23-HEXATHIA[9](1,2)[9](4,5)CYCLOPHANE AND ETRATHIA[9](1,3)[9](4,6)-2,5-BIS(ETHOXY)CYCLOPHANE

The Cs+/DMF mediated reactions of 1,2,4,5-tetra(bromomethyl) benzene a nd 1,2,4,5-tetra(bromomethyl)3,6-bis(ethoxy)benzene with dithiols HSCH (2)CH(2)XCH(2)CH(2)SH (X = S,O) were explored in order in order to asc ertain 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) st ructure. Two crystal structures, one with a bis(ortho) structure, 2,5, 8,17,20,23-hexathia[9](1,2)[9](4,S)cyclophane, 1, and one with a bis(m eta) structure, trathia[9](1,3)[9](4,6)-2,5-bis(ethoxy)cyclophane, 7, are reported. 1 crystallized in the triclinic space group P $($) over bar$$ 1 with a = 8.583(3), b = 11.806(3), c = 5.448(2) Angstrom, alpha = 97.18(2), beta = 107.18(2), gamma = 99.40(2)degrees, V = 511.6(6) A ngstrom(3), and Z = 1. The structure refined to R = 6.48% and R(w) = 7 .13% for 1020 reflections with F-0(2) > 3 sigma(F-0(2)). 7 crystallize d in the triclinic space group P $($) over bar$$ 1 with a = 9.568(2), b = 9.577(2), c = 8.312(2) Angstrom, alpha = 113.53(2), beta = 94.58(2 ), gamma = 114.94(2)degrees, V = 604.3(7) Angstrom(3), and Z = 1. The structure refined to R = 3.86% and R(w) = 4.20% for 1129 reflections w ith F-0(2) > 3 sigma(F-2(0)). Both compounds sit on a crystallographic centre of symmetry and have the thioether linkages oriented on opposi te sides of the central aromatic ring.