title: Chiral Nanostructures from Helical Copolymer-Metal Complexes: Tunable Cation-π Interactions and Sergeants and Soldiers Effect.
abstract: Poly(phenylacetylene) (PPA) copolymers containing (R)- or (S)-MPA as minor chiral pendant can be forced to selectively adopt the right- o left-handed helix, in the presence of small amounts of Na(+) or Ag(+) ("Sergeants and Soldiers Effect") by addition of a donor cosolvent. The helical sense depends exclusively on the chiral monomer/donor cosolvent ratio, and this allows a perfect on/off tuning of the helicity of the copolymer. When the amount of the donor cosolvent is low, the metal ion complex is stabilized by a cation-π interaction, which is selectively cleaved when the amount of cosolvent is higher. Macroscopically chiral nanospheres and nanotubes composed by helical copolymers with P or M helical sense are also described. Our results demonstrate that it is possible to obtain the two enantiomeric helical structures (P and M helicities) and the corresponding nanospheres and nanotubes from a single helical copolymer, by controlled activation/deactivation of the Sergeant and Soldiers Effect with a donor cosolvent.
authors.affiliation: Centre for Research in Biological Chemistry and Molecular Materials (CIQUS), University of Santiago de Compostela, 15782, Santiago de Compostela, Spain.
authors.forename: Sandra
authors.initials: S
authors.lastname: Arias
authors.affiliation: Centre for Research in Biological Chemistry and Molecular Materials (CIQUS), University of Santiago de Compostela, 15782, Santiago de Compostela, Spain.
authors.forename: Julián
authors.initials: J
authors.lastname: Bergueiro
authors.affiliation: Centre for Research in Biological Chemistry and Molecular Materials (CIQUS), University of Santiago de Compostela, 15782, Santiago de Compostela, Spain.
authors.forename: Félix
authors.initials: F
authors.lastname: Freire
authors.affiliation: Centre for Research in Biological Chemistry and Molecular Materials (CIQUS), University of Santiago de Compostela, 15782, Santiago de Compostela, Spain.
authors.forename: Emilio
authors.initials: E
authors.lastname: Quiñoá
authors.affiliation: Centre for Research in Biological Chemistry and Molecular Materials (CIQUS), University of Santiago de Compostela, 15782, Santiago de Compostela, Spain.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Riguera
keywords: cation-π; enantiomeric nanostructures; helicity; poly(phenylacetylene)s; sergeants and soldiers