Abstract

Oligo(benzoate) derivatives, (R)[9]aneNS₂, of 1,4-dithia-7-azacyclononane [R = OC-C₆H₄-4-OR′ (1) [R′ = C₃H₇ (a) C₈H₁₇ (b)], OC-C₆H₄-4-O₂C-C₆H₄-4-OC₈H₁₇ (2), OC-C₆H₄-4-O₂C-C₆H₄-4-O₂C-Z, Z = C₆H₄-4-OC₈H₁₇ (3), C₆H₃-3,4-(OR′₂)₂ (4) [R′ = C₄H₉ (a), C₈H₁₇ (b), C₁₂H₂₅ (c)], C₆H₂-3,4,5-(OC₁₂H₂₅)₃ (5)] have been synthesised. Compound 3 displays monotropic nematic and smectic phases, while 5 shows an enantiotropic columnar hexagonal phase (Col_h) just above room temperature as characterised by X-ray scattering experiments. Dilatometry suggests a model for the packing of molecules of 5 in the mesophase. An alternative route to these compounds has been developed via the preparation of the protected species 6 [R = OC-C₆H₄-4-OC(O)OMe], which can be deprotected using aqueous NH₃ to give 7 [R = OC-C₆H₄-4-OH], followed by reaction with the appropriate acid chloride or anhydride. Oligo(benzoate) derivatives, (R)₂[9]aneN₂S, of 1-thia-4,7-diazacyclononane [R = OC-C₆H₄-4-OC(O)OMe (8), OC-C₆H₄-4-OH (9) OC-C₆H₄-4-O₂C-C₆H₄-4-OC₈H₁₇ (10), OC-C₆H₄-4-O₂C-C₆H₂-3,4,5-(OC₁₂H₂₅)₃ (11)] have been prepared as transesterification products.