title: A compact tetrathiafulvalene-benzothiadiazole dyad and its highly symmetrical charge-transfer salt: ordered donor π-stacks closely bound to their acceptors.
abstract: A compact and planar donor-acceptor molecule 1 comprising tetrathiafulvalene (TTF) and benzothiadiazole (BTD) units has been synthesised and experimentally characterised by structural, optical, and electrochemical methods. Solution-processed and thermally evaporated thin films of 1 have also been explored as active materials in organic field-effect transistors (OFETs). For these devices, hole field-effect mobilities of μFE = (1.3±0.5)×10(-3) and (2.7±0.4)×10(-3)  cm(2)  V s(-1) were determined for the solution-processed and thermally evaporated thin films, respectively. An intense intramolecular charge-transfer (ICT) transition at around 495 nm dominates the optical absorption spectrum of the neutral dyad, which also shows a weak emission from its ICT state. The iodine-induced oxidation of 1 leads to a partially oxidised crystalline charge-transfer (CT) salt {(1)2I3}, and eventually also to a fully oxidised compound {1I3}⋅1/2I2. Single crystals of the former CT compound, exhibiting a highly symmetrical crystal structure, reveal a fairly good room temperature electrical conductivity of the order of 2 S cm(-1). The one-dimensional spin system bears compactly bonded BTD acceptors (spatial localisation of the LUMO) along its ridge.
authors.affiliation: Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, 3012 Bern (Switzerland), Fax: (+41) 31-631-3995.
authors.forename: Yan
authors.initials: Y
authors.lastname: Geng
authors.forename: Raphael
authors.initials: R
authors.lastname: Pfattner
authors.forename: Antonio
authors.initials: A
authors.lastname: Campos
authors.forename: Jürg
authors.initials: J
authors.lastname: Hauser
authors.forename: Vladimir
authors.initials: V
authors.lastname: Laukhin
authors.forename: Joaquim
authors.initials: J
authors.lastname: Puigdollers
authors.forename: Jaume
authors.initials: J
authors.lastname: Veciana
authors.forename: Marta
authors.initials: M
authors.lastname: Mas-Torrent
authors.forename: Concepció
authors.initials: C
authors.lastname: Rovira
authors.forename: Silvio
authors.initials: S
authors.lastname: Decurtins
authors.forename: Shi-Xia
authors.initials: SX
authors.lastname: Liu
mesh_terms: D018360:Crystallography, X-Ray; D004553:Electric Conductivity; D055664:Electrochemical Techniques; D006571:Heterocyclic Compounds / Q000737:chemistry*; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D011789:Quantum Theory; D012492:Salts / Q000737:chemistry; D013830:Thiadiazoles / Q000737:chemistry*; D014173:Transistors, Electronic
chemical_list: D006571:Heterocyclic Compounds; D012492:Salts; D013830:Thiadiazoles; C015700:benzo-1,2,3-thiadiazole; C063887:tetrathiafulvalene
keywords: charge transfer; donor-acceptor systems; electrical conductivity; organic field-effect transistor; tetrathiafulvalene-benzothiadiazole