Conjugated double helices via self-dimerization of α,α'-dianilinotripyrrins.

ABSTRACT: A new motif for artificial double helices was developed on the basis of α,α'-disubstituted tripyrrin. α,α'-Dibromotripyrrin 3 was prepared by gentle bromination at the pyrrolic α-positions of 5,10-diphenyltripyrrane followed by oxidation with DDQ. Nucleophilic substitution reactions of 3 with anilines proceeded efficiently to furnish a series of α,α'-dianilinotripyrrins 4-11, which displayed monomeric and dimeric forms depending upon the solvent used for crystallization and the structures of the substituted anilines. Dimeric forms show double helical structures with smooth π-conjugation as indicated by their absorption spectra. van't-Hoff plot analyses revealed that the dimerizations in CDCl₃ are enthalpy-driven. Larger association constants of the dimerizat

SUBMITTER: Umetani M 

PROVIDER: S-EPMC6114996 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature