Oxa-bridged cyclophanes featuring thieno[2,3-b]thiophene and C2-symmetric binol or bis-naphthol rings: synthesis, structures, and conformational studies

The structures of oxa-bridged cyclophanes were determined with the aid of 2D NMR analysis. Dynamic NMR study revealed that the conformations of cyclophanes are temperature dependent with the binol cyclophanes 4/6 having higher energy barriers relatively to the corresponding bis-naphthol cyclophanes 8/10.