title: Cooperatively Interlocked [2+1]-Type π-System-Anion Complexes.
abstract: As fascinating examples of closely connected multiple π-electronic systems involving noncovalent interactions, the cooperatively interlocked [2+1]-type anion complexes of well-designed π-electronic molecules are reported. The anion-responsive π-electronic molecules investigated in this study are the boron complexes of dipyrrolyldiketones bearing arylethynyl moieties at the pyrrole α-positions. Diverse substituents were introduced at the terminal aryl moieties, thus controlling the cooperativity to form [2+1]-type complexes. Theoretical studies showed that this cooperativity was induced by effective interactions between the introduced arylethynyl moieties. The investigations of the anion-binding processes showed that the first and second bindings to the guest anion were energetically almost equivalent, indicating the fundamental and important features of the electronic states of the halide anions. Furthermore, the interlocked anion complexes, whose geometries were distorted from the orthogonal arrangements, had the racemic states of the chiral conformations, either of which was induced by ion pairing with an appropriate chiral π-electronic cation, resulting in the chiroptical property as shown by circular dichroism.
authors.affiliation: Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University, Kusatsu, 525-8577, Japan.
authors.forename: Ryohei
authors.initials: R
authors.lastname: Yamakado
authors.affiliation: Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University, Kusatsu, 525-8577, Japan.
authors.forename: Yukina
authors.initials: Y
authors.lastname: Ashida
authors.affiliation: Department of Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, 305-8577, Japan.
authors.forename: Ryuma
authors.initials: R
authors.lastname: Sato
authors.affiliation: Department of Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, 305-8577, Japan.
authors.forename: Yasuteru
authors.initials: Y
authors.lastname: Shigeta
authors.affiliation: Research and Utilization Division, Japan Synchrotron Radiation Research Institute, Sayo, 679-5198, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Yasuda
authors.affiliation: Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University, Kusatsu, 525-8577, Japan.
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Maeda
keywords: anions; cooperative effects; interlocked complexes; ion pairing; pi interactions