title: Reversible Dimerization and Polymerization of a Janus Diradical To Produce Labile C-C Bonds and Large Chromic Effects.
abstract: Conducting polymers can be synthesized by irreversible diradical monomer polymerization. A reversible version of this reaction consisting of the formation/dissociation of σ-dimers and σ-polymers from a stable quinonoidal diradical precursor is described. The reaction reversibility is made by a quinonoidal molecule which changes its structure to an aromatic species by forming weak and long intermolecular C-C single bonds. The reaction provokes a giant chromic effect of about 2.5 eV. The two opposite but complementary quinonoidal and aromatic tautomers provide the Janus faces of the reactants and products which produces the observed chromic effect. A reaction mechanism is proposed to explain the variety of final products starting with structurally very similar reactants. These reversible reactions, covering an unusual regime of weak covalent supramolecular bonding, yield products which might be envisaged as novel molecular and polymeric soft matter phases.
authors: Department of Physical Chemistry, University of Málaga, 29071, Málaga, Spain.
authors: José L
authors: JL
authors: Zafra
authors: Department of Chemistry and Institute of Soft Matter, Georgetown University, Washington, D.C., 20057-1227, USA.
authors: Lili
authors: L
authors: Qiu
authors: Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University Kagamiyama, Higashi-Hiroshima, 739-8527, Japan.
authors: Naoyuki
authors: N
authors: Yanai
authors: Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University Kagamiyama, Higashi-Hiroshima, 739-8527, Japan.|Emergent Molecular Function Research Group, RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
authors: Takamichi
authors: T
authors: Mori
authors: Emergent Molecular Function Research Group, RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
authors: Masahiro
authors: M
authors: Nakano
authors: Department of Physical Chemistry, Complutense University of Madrid, 28040, Madrid, Spain.
authors: Miriam Peña
authors: MP
authors: Alvarez
authors: Department of Physical Chemistry, University of Málaga, 29071, Málaga, Spain.
authors: Juan T López
authors: JT
authors: Navarrete
authors: Instituto de Ciencia Molecular, Universidad de Valencia, 46980 Paterna, Valencia, Spain.
authors: Carlos J
authors: CJ
authors: Gómez-García
authors: Department of Chemistry and Institute of Soft Matter, Georgetown University, Washington, D.C., 20057-1227, USA.
authors: Miklos
authors: M
authors: Kertesz
authors: Emergent Molecular Function Research Group, RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
authors: Kazuo
authors: K
authors: Takimiya
authors: Department of Physical Chemistry, University of Málaga, 29071, Málaga, Spain.
authors: Juan
authors: J
authors: Casado
keywords: cyclophanes; density functional calculations; radicals; reaction mechanisms; solvatochromism