Electron-transporting phenazinothiadiazoles with engineered microstructure

Lindner, Benjamin; Paulus, Fabian; Appleton, Anthony L.; Schaffroth, Manuel; Engelhart, Jens U.; Schelkle, Korwin M.; Tverskoy, Olena; Röminger, Frank; Hamburger, Manuel; Bunz, Uwe H. F.

doi:10.1039/c4tc01992j

Cited by 49 publications

(51 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As shown in Figures 3c and 3d, TIPS-PhNTQ exhibits a 2D arrangement with interlayer distances of 3.34 and 3.44 Å. 43 TIPS-BisPhNPQ displays a 2D brickwork packing arrangement, same as the packing styles of TIPS-pentacene and TIPS-tetraazapentacene. 10,13,32 The distances between π planes in the molecule of TIPS-BisPhNPQ are 3.32 and 3.34 Å, which are shorter than those in TIPS-pentacene (3.47 Å).…”

Section: ■ Results and Discussionmentioning

confidence: 84%

Highly Ordered Phenanthroline-Fused Azaacene

An¹,

Guo²,

Baumgarten³

2015

Crystal Growth & Design

View full text Add to dashboard Cite

A new synthetic route to prepare a centrosymmetric phenanthroline-fused azaacene derivative, TIPSBisPhNPQ, is described. Another axialsymmetric analogue, TIPS-PhNTQ, is also synthesized for comparison. Cyclic voltammetry measurements indicate high electron affinity values of −4.03 and −4.01 eV for TIPS-PhNTQ and TIPSBisPhNPQ, respectively. Single-crystal X-ray diffraction reveals that TIPS-PhNTQ forms dimers by intermolecular S−N and N−N interaction, while TIPS-BisPhNPQ shows a highly ordered arrangement via two-dimensional brickwork packing and intermolecular hydrogen bonding. The synthetic protocol established in this paper should be highly applicable to the preparation of more azaacene derivatives with extended π-conjugations. ■ INTRODUCTIONLarge acenes, particularly exemplified by pentacene, have been paid great attention in organic field-effect transistors (OFET). 1−5 The molecular size and structure of acenes are very important for their optoelectronics properties, 6 but their solubility and stability gradually decrease with increasing numbers of aromatic fused ring. 7−9 Three strategies are usually used to stabilize large linear acenes: (1) Introducing special substituents into the acenes backbone, like triisopropylsily (TIPS) acetylene 10 and tritertbutylsilyl (TTBS) acetylene, 11 which can stabilize the LUMO level and prevent singlet oxygen sensitization by lowering the molecular triplet energy; 12 (2) Replacing tertiary carbon atom (C−H) moieties using imine nitrogen atoms (−N) in acenes backbone increases the stabilization of their HOMO and LUMO levels to obtain linear extended azaacenes; 13−23 (3) Expanding laterally the conjugation of the linear aromatic backbone using aromatic rings, such as pyrene-fused azaacenes, 24−29 where the sextet of π electrons are localized on the external rings. Additionally, previous computational studies by Winkler and Houk 30 indicated that replacing a CH moiety by a nitrogen atom or grafting one cyano group onto the terminal ring at both sides can help formation of intermolecular interconnection by hydrogen bonds (C−H···N). More interestingly, combination of these features with molecular π−π stacking can create a highly ordered two-dimensional (2D) arrangement. However, such azaacene molecules are rarely synthesized because of a lack of effective synthetic protocols.Currently, a very common approach for preparing soluble TIPS-azaacences is the nucleophilic addition between TIPSethynyl anion and corresponding dione azaazcenes. 13,31,32 However, it suffers from a difficulty in synthesizing the key dione azaacenes for further extending conjugation of TIPSazaacenes due to their very poor solubility. Ideally, for the purpose of synthesizing highly conjugated centrosymmetric TIPS-azaacences, it would be desirable to use a TIPS-ethynyl containing intermediate compound as a reactant, which yields directly soluble TIPS-azaacenes during the condensation step, without a postfunctionalization.With all of these in mind, herein we report a convenient synthetic route for preparing a...

show abstract

Section: ■ Results and Discussionmentioning

confidence: 84%

Highly Ordered Phenanthroline-Fused Azaacene

An¹,

Guo²,

Baumgarten³

2015

Crystal Growth & Design

View full text Add to dashboard Cite

show abstract

“…1,2,5-Thiadiazoles have proven to be strong electron acceptor moieties and their derivatives [8] have been widely applied as key building blocks for organic semiconducting materials.Herein, we synthesized the thiadiazole end-capped layered molecules D1-4 through dimerization of hetero-acenes.Aone-pot reaction is employed in which formation of thiadiazole rings and dimerization are accomplished using di-and tetraamino-substituted acene precursors 3a-c (Scheme 1). It is believed that introduction of electronwithdrawing thiadiazole rings increases the quinoid character of the conjugated system, and thus leads to dimerization without the involvement of light or oxygen.…”

mentioning

confidence: 99%

Layered Electron Acceptors by Dimerization of Acenes End‐ Capped with 1,2,5‐Thiadiazoles

et al. 2015

View full text Add to dashboard Cite

Layered electron acceptors D1-4 equipped with terminal 1,2,5-thiadiazole groups have been constructed using a one-pot protocol of acene dimerization. Their molecular structures are determined using single-crystal X-ray diffraction analysis. Photophysical and electrochemical properties of these molecules present a marked dependence on conjugation length and molecular geometry. An aggregation-induced emission peak and an intramolecular excimer emission (IEE) band were observed for D2 and D4, respectively. This work paves the way for the efficient synthesis of layered heteroacenes.

show abstract

“…In attempts to reduce 1, the diamine 2 forms, 5 but further reduction was unsuccessful, even with an Scheme 1 Reduction of 1 by LiAlH4 stops at the mono(thiadiazole) stage 2 (TIPS = triisopropylsilyl). 5 excess of LiAlH 4 or NaBH 4 . We therefore expanded the choice of reducing agents.…”

mentioning

confidence: 99%