title: Probing the dynamic environment-associated conformational conversion from secondary to supersecondary structures in oligo(phenanthroline dicarboxamide)s.
abstract: The special structural features of the oligo(phenanthroline dicarboxamide)s and their dynamic environment-associated conformational conversion from secondary helical structure to supersecondary helix-turn structure, owing to the conversion of the CONH bond from s-cis form to s-trans form, have been experimentally and theoretically characterized by X-ray crystallographic, variable-temperature (1)H NMR, variable-temperature circular dichroism techniques, and computational studies. It has been demonstrated that the solvent effects together with intramolecular hydrogen bonds and pi-pi stacking play a key role in stabilizing both the secondary and supersecondary structures. Furthermore, by introducing the intramolecular F...H-N hydrogen bond to restrict the rotation about the CONH-aryl bonds, the oligomers 6 and 7 have been synthesized, which showed well-defined and predictable secondary helical conformations in solution and in the solid state.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Hai-Yu
authors.initials: HY
authors.lastname: Hu
authors.forename: Wei
authors.initials: W
authors.lastname: Xue
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Hu
authors.forename: Jun-Feng
authors.initials: JF
authors.lastname: Xiang
authors.forename: Chuan-Feng
authors.initials: CF
authors.lastname: Chen
authors.forename: Sheng-Gui
authors.initials: SG
authors.lastname: He