A study of the conformation of some chiral binaphthyl and bithienyl derivatives in the solid state and in solution. An approach by X-ray diffraction, circular dichroism spectroscopy and induced cholesteric mesophase analysis

Abstract

The crystal structures of enantiomeric 4,5,6,7-tetrahydrodinaphtho[2,1-b:1′,2′-d][1,6]dioxecine, 1a, and of enantiomeric dimethyl 2,2′-dinitro-3,3′-bithienyl-4,4′,-dicarboxylate, 3, are reported. The solid state conformations of these compounds and of related derivatives with bridged and non-bridged 1,1′-binaphthyl structures are analysed. The conformation in the crystal structure is compared with the conformation in solution obtained from the twisting powers of these compounds in nematic liquid crystal solvents and from circular dichroism measurements. For quasi-rigid bridged binaphthyls the different sets of data agree. For mobile biaryls they may differ.