title: Towards Magnetic Carbo-meric Molecular Materials.
abstract: Numerous studies have underlined the putative diradical character of π-conjugated molecules that can be described by closed-shell Lewis structures, for instance, p-dimethylene p-n phenylenes, or long polyacenes. In the latter compounds, the only way to save the aromaticity of the six-membered rings is to give up the Lewis electron pairing in the singlet biradical ground state. The present work considers the possibility of doing the same by using the basic C2 units of carbo-meric architectures. A series of acyclic and cyclic carbo-meric architectures is studied by using UB3LYP DFT broken-symmetry calculations, including spin decontaminations and subsequent geometry optimization of the singlet diradical. The C2 units are shown to stabilize the singlet biradical by spin delocalization, two of them playing approximately the same role as one radical-insulating 1,4 phenylene moiety. The results are generalized to the investigation of open-shell polyradical singlet states of rigid hydrocarbon structures, the symmetry and rigidity of which can assist cooperativity and self spin polarization effect. Several synthesis targets with challenging magnetic/spin properties are suggested in the carbo-mer series.
authors.affiliation: CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, BP 44099, 31077, Toulouse Cedex 4, France. corentin.poidevin87@gmail.com.|Université de Toulouse, UPS, INP, 31077, Toulouse Cedex 4, France. corentin.poidevin87@gmail.com.
authors.forename: Corentin
authors.initials: C
authors.lastname: Poidevin
authors.affiliation: Laboratoire de Chimie et Physique Quantiques, UMR 5626 (CNRS), IRSAMC, Université P. Sabatier, 118 Rte de Narbonne, 31062, Toulouse Cedex, France. jean-paul.malrieu@irsamc.ups-tlse.fr.
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Malrieu
authors.affiliation: Laboratoire de Chimie et Physique Quantiques, UMR 5626 (CNRS), IRSAMC, Université P. Sabatier, 118 Rte de Narbonne, 31062, Toulouse Cedex, France.
authors.forename: Georges
authors.initials: G
authors.lastname: Trinquier
authors.affiliation: CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, BP 44099, 31077, Toulouse Cedex 4, France. christine.lepetit@lcc-toulouse.fr.|Université de Toulouse, UPS, INP, 31077, Toulouse Cedex 4, France. christine.lepetit@lcc-toulouse.fr.
authors.forename: Christine
authors.initials: C
authors.lastname: Lepetit
authors.affiliation: Physico Chimie des Processus de Combustion, et de l'Atmosphère (PC2 A), UMR 8522, CNRS/Lille 1, Université Lille 1 Sciences et Technologies, Cité scientifique, 59655, Villeneuve d'Ascq Cedex, France.
authors.forename: Faycal
authors.initials: F
authors.lastname: Allouti
authors.affiliation: Sorbonne Universités, UPMC Univ. Paris 06, MONARIS, UMR 8233, Université Pierre et Marie Curie, 4 Place Jussieu, Case courrier 49, 75252, Paris Cedex 05, France.|CNRS, MONARIS, UMR 8233, Université Pierre et Marie Curie, 4 Place Jussieu, Case courrier 49, 75252, Paris Cedex 05, France.
authors.forename: M Esmail
authors.initials: ME
authors.lastname: Alikhani
authors.affiliation: CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, BP 44099, 31077, Toulouse Cedex 4, France. remi.chauvin@lcc-toulouse.fr.|Université de Toulouse, UPS, INP, 31077, Toulouse Cedex 4, France. remi.chauvin@lcc-toulouse.fr.
authors.forename: Remi
authors.initials: R
authors.lastname: Chauvin
keywords: carbo-mers; density functional calculations; magnetic properties; singlet multiradical hydrocarbons; spin decontamination