A Compact Tetrathiafulvalene–Benzothiadiazole Dyad and Its Highly Symmetrical Charge‐Transfer Salt: Ordered Donor π‐Stacks Closely Bound to Their Acceptors. Issue 23 (15th April 2014)

• Record Type: Journal Article
• Authors: Geng, Yan; Pfattner, Raphael; Campos, Antonio; Hauser, Jürg; Laukhin, Vladimir; Puigdollers, Joaquim; Veciana, Jaume; Mas‐Torrent, Marta; Rovira, Concepció; Decurtins, Silvio; Liu, Shi‐Xia
• Is Part Of: Chemistry. Volume 20:Issue 23(2014)
• Page Start: 7136
• Page End: 7143
• Publication Date: 2014-04-15
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201304688
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A compact and planar donor–acceptor molecule <bold>1</bold> 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 <bold>1</bold> have also been explored as active materials in organic field‐effect transistors (OFETs). For these devices, hole field‐effect mobilities of <italic>μ</italic><sub>FE</sub>=(1.3±0.5)×10<sup>−3</sup> and (2.7±0.4)×10<sup>−3</sup> cm<sup>2</sup> V s<sup>−1</sup> 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 <bold>1</bold> leads to a partially oxidised crystalline charge‐transfer (CT) salt {(<bold>1</bold>)<sub>2</sub>I<sub>3</sub>}, and eventually also to a fully oxidised compound {<bold>1</bold>I<sub>3</sub>}<bold>⋅</bold>1/2I<sub>2</sub>. 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<sup>−1</sup>. The one‐dimensional spin system bears compactly bonded BTD acceptors (spatial localisation of the LUMO) along its ridge.</p> </abstract>