title: Synthesis and characterization of a novel terthiophene-based quinodimethane bearing a 3,4-ethylenedioxythiophene central unit.
abstract: The synthesis and a combined spectroscopic and density functional theoretical characterization of a 3',4'-ethylenedioxy-5,5' '-bis(dicyanomethylene)-5,5' '-dihydro-2,2':5',2' '-terthiophene analogue of 7,7,8,8-tetracyanoquinodimethane (TCNQ) are presented. Electrochemical data show that this novel trimer can be both reversibly reduced and oxidized at relatively low potentials. Quantum-chemical calculations show that the compound exhibits a quinoidal structure in its ground electronic state and that a certain degree of intramolecular charge transfer takes place from the central terthienyl moiety toward both =C(CN)2 end-caps. Therefore, the amphoteric redox behavior of this novel material can be related to the coexistence of an electron-impoverished terthienyl core endowed by two electron-enriched =C(CN)2 substituents. The UV-vis spectrum is dominated by the appearance of a strong absorption near 660 nm, attributable to the highest occupied molecular orbital (HOMO) --> lowest unoccupied molecular orbital (LUMO) pi-pi electronic transition of the terthienyl spine on the basis of time-dependent density functional theory (DFT) computations. The DFT calculations performed on the minimum-energy molecular geometry about the equilibrium atomic charge distribution, topologies, and energies of the frontier orbitals around the gap and about the Raman-active vibrations associated with the strongest Raman features are also consistent with a rather effective pi-electron conjugation and the partial degree of intramolecular charge transfer mentioned above. Our study reveals this novel heteroquinoid trimer could act as a promising candidate in organic field-effect transistor (OFET) applications.
authors.affiliation: Istituto CNR di Scienze e Tecnologie Molecolari, via C. Golgi 19, 20133 Milano, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Berlin
authors.forename: Sara
authors.initials: S
authors.lastname: Grimoldi
authors.forename: Gianni
authors.initials: G
authors.lastname: Zotti
authors.forename: Reyes Malavé
authors.initials: RM
authors.lastname: Osuna
authors.forename: Mari Carmen
authors.initials: MC
authors.lastname: Ruiz Delgado
authors.forename: Rocío Ponce
authors.initials: RP
authors.lastname: Ortiz
authors.forename: Juan
authors.initials: J
authors.lastname: Casado
authors.forename: Víctor
authors.initials: V
authors.lastname: Hernandez
authors.forename: Juan T
authors.initials: JT
authors.lastname: López Navarrete
mesh_terms: D004563:Electrochemistry; D008697:Methane / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry; D008956:Models, Chemical; D015394:Molecular Structure; D009570:Nitriles / Q000138:chemical synthesis* / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013059:Spectrum Analysis, Raman / Q000379:methods; D013876:Thiophenes / Q000737:chemistry*
chemical_list: C521515:5,5''-bis(dicyanomethylene)-3',4'-ethylenedioxy-5,5''-dihydro-2,2'-5',2''-terthiophene; D009570:Nitriles; D013876:Thiophenes; C013703:tetracyanoquinodimethane; D008697:Methane