title: Enantiopure double-helical phenylene ethynylene cyclophynes with the 2,2'-binaphthyl template.
abstract: New types of enantiopure compounds were synthesized to gain better insight into the structural features of phenylene ethynylene cyclophynes. Besides the previously obtained meta-substituted arylene ethynylenes, 1, ortho-connected phenylene ethynylene units were incorporated to give cyclophynes with ortho/meta and ortho/ortho connection modes, 2 and 3. Furthermore, a diphenylethyne component was also accommodated in 4. Both ab initio calculations and NMR spectra suggest a large amount of strain for 2 but less strain for 3 and 1 a, the latter having the smallest ring size among cyclophynes with the meta/meta connection mode. The CD spectra of 2 and 3 showed a characteristic shoulder at around 340 nm, similar to the case of 1 a. This implies that the aromatic acetylene bonds cross over each other in the double-helical structure. These results indicate that chirality information is useful for probing the persistency of molecular shape.
authors.affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China. deliean@sina.com
authors.forename: De-Lie
authors.initials: DL
authors.lastname: An
authors.forename: Ying-Jun
authors.initials: YJ
authors.lastname: Zhang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Chen
authors.forename: Wen-Ying
authors.initials: WY
authors.lastname: Zhao
authors.forename: Hong
authors.initials: H
authors.lastname: Yan
authors.forename: Akihiro
authors.initials: A
authors.lastname: Orita
authors.forename: Junzo
authors.initials: J
authors.lastname: Otera