Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

• Valentin H. K. Fell,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Eman J. Hussien and
• Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

• 10.3762/bjoc.18.94 Abstract A novel π-conjugated molecule, EtH-T-DI-DTT is reported, which is fused, rigid, and planar, featuring the electron-rich dithieno[3,2-b:2’,3’-d]thiophene (DTT) unit in the core of the structure. Adjacent to the electron-donating DTT core, there are indenone units with electron

• moieties within a π-electron system are twisted with respect to each other, preventing efficient overlap of p-orbitals of adjacent carbon atoms [15]. To prevent that, there is a large interest in creating rigid, planar molecules with low or no rotational degrees of freedom. This can be achieved by fusing π

• -conjugated ring structures [15]. In the solid state, fused systems are prone to form highly ordered π–π-stacked structures [16], leading to better bulk charge transport [17]. Another important aspect is solubility, which is generally poor in larger conjugated molecules [3]. This is even aggravated for fused

Post-synthesis from Lewis acid–base interaction: an alternative way to generate light and harvest triplet excitons

• Hengjia Liu and
• Guohua Xie

Beilstein J. Org. Chem. 2022, 18, 825–836, doi:10.3762/bjoc.18.83

• (C6F5)3 (BCF) to bind to nitrogen atoms at the basic site a of π-conjugated polymer, providing a simple strategy to regulate the optical properties of the A–D–A chromophore with charge transfer excited state properties [28]. In 2019, Wang et al. constructed a novel exciplex system by using the Lewis

• with BF3, BBr3, and AlCl3, respectively, mixed in the low bandgap conjugated polymer materials. This is ascribed to the formation of Lewis acid–base adducts [34]. Fluorescent materials as electron donors Hancock et al. compared the PL and EL spectra of the π-conjugated heterocyclic oligomer 6,6’-bis(2

• 7 in Figure 5), which consisted of the twisted A–π–D–π–A structure with N-(4-aminophenyl)carbazole (CzPA) as electron donor unit, pyridine as electron acceptor unit, and 9,9-dioctylfluorene (F) as π-conjugated linker [32]. Compound 7 showed remarkable dual-fluorescence properties when mixed with a

Synthesis and investigation on optical and electrochemical properties of 2,4-diaryl-9-chloro-5,6,7,8-tetrahydroacridines

• Najeh Tka,
• Mohamed Adnene Hadj Ayed,
• Mourad Ben Braiek,
• Mahjoub Jabli and
• Peter Langer

Beilstein J. Org. Chem. 2021, 17, 2450–2461, doi:10.3762/bjoc.17.162

• their HOMO/LUMO energy levels were estimated by cyclic voltammetry measurements. Besides, density functional theory calculations were carried out for further exploration of their electronic properties. Keywords: catalysis; cross-coupling; cyclization; fluorescence; palladium; Introduction π-Conjugated

• organic molecules are finding use in numerous areas ranging from organic electronics [1][2][3][4][5], ions sensing [6][7], and solar cell development [8][9][10]. Within this background, acridines represent an interesting class of heteroaromatic π-conjugated compounds [11][12][13][14] which show great

• product 4a. As well, the phenyl ortho-substituent in the aryl ring for 4f was twisted out of the plane and was not involved in the electronic orbital distribution (Figure 8). As shown in Figure 9, the HOMO and LUMO frontier orbitals of products 4a–d are extended over the π-conjugated part of the molecules

2,4-Bis(arylethynyl)-9-chloro-5,6,7,8-tetrahydroacridines: synthesis and photophysical properties

• Najeh Tka,
• Mohamed Adnene Hadj Ayed,
• Mourad Ben Braiek,
• Mahjoub Jabli,
• Noureddine Chaaben,
• Kamel Alimi,
• Stefan Jopp and
• Peter Langer

Beilstein J. Org. Chem. 2021, 17, 1629–1640, doi:10.3762/bjoc.17.115

• molecules have been examined. Additionally, theoretical studies based on density functional theory (DFT/B3LYP/6-31G(d)) were carried out. Keywords: alkynes; catalysis; cross-coupling; heterocycles; palladium; Introduction The development and design of small π-conjugated molecules have attracted increasing

Recent advances in the application of isoindigo derivatives in materials chemistry

• Andrei V. Bogdanov and
• Vladimir F. Mironov

Beilstein J. Org. Chem. 2021, 17, 1533–1564, doi:10.3762/bjoc.17.111

• possibility of varying optoelectronic properties, and good solubility in a wide range of solvents [59][60][61]. In this regard, the most studied and promising are π-conjugated polymer structures based on sulfur, oxygen, nitrogen, and selenium heterocyclic compounds [62][63]. One of the systems for creating

Design, synthesis and photophysical properties of novel star-shaped truxene-based heterocycles utilizing ring-closing metathesis, Clauson–Kaas, Van Leusen and Ullmann-type reactions as key tools

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2021, 17, 1374–1384, doi:10.3762/bjoc.17.96

• properties (absorption and emission) for these versatile systems has been revealed. Keywords: Clauson–Kaas reaction; heterocycles; ring-closing metathesis; truxene; Ullmann-type coupling; Van Leusen reaction; Introduction The two-dimensional phenylene-based π-conjugated star-shaped architectures has

• recently attracted a tremendous attention of the researchers across the globe because of their inimitable physiochemical properties, processability and availability [1][2][3][4]. Interestingly, compared to the π-conjugated one-dimensional rod-shaped architectures, two-dimensional star-shaped systems hold

Synthesis of dibenzosuberenone-based novel polycyclic π-conjugated dihydropyridazines, pyridazines and pyrroles

• Ramazan Koçak and
• Arif Daştan

Beilstein J. Org. Chem. 2021, 17, 719–729, doi:10.3762/bjoc.17.61

• Ramazan Kocak Arif Dastan Department of Chemistry, Faculty of Sciences, Atatürk University, Erzurum, 25240, Turkey 10.3762/bjoc.17.61 Abstract The synthesis of novel polycyclic π-conjugated dihydropyridazines, pyridazines, and pyrroles was studied. Dihydropyridazine dyes were synthesized by

• obtained gave absorbance and emission at long wavelengths. Keywords: dibenzosuberenone; inverse electron-demand Diels–Alder cycloaddition reactions; p-quinone methide; polycyclic π-conjugated dihydropyridazines; pyridazines; pyrroles; Inroduction Dibenzosuberone and dibenzosuberenone derivatives are

• exhibit photophysical properties such as photosensitization [13], fluorescence, and aggregation-induced emission (AIE) [14][15][16]. π-Conjugated polycyclic hydrocarbons (CPHs) containing polycyclic heteroaromatic molecules (PHAs) and aza-polycyclic aromatic hydrocarbons (aza-PAHs) have been attracting

Synthesis, structural characterization, and optical properties of benzo[f]naphtho[2,3-b]phosphoindoles

• Mio Matsumura,
• Takahiro Teramoto,
• Masato Kawakubo,
• Masatoshi Kawahata,
• Yuki Murata,
• Kentaro Yamaguchi,
• Masanobu Uchiyama and
• Shuji Yasuike

Beilstein J. Org. Chem. 2021, 17, 671–677, doi:10.3762/bjoc.17.56

• Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan Research Initiative for Supra-Materials (RISM), Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan 10.3762/bjoc.17.56 Abstract Phosphole-fused π-conjugated acenes have been

Synthesis, crystal structures and properties of carbazole-based [6]helicenes fused with an azine ring

• Daria I. Tonkoglazova,
• Anna V. Gulevskaya,
• Konstantin A. Chistyakov and
• Olga I. Askalepova

Beilstein J. Org. Chem. 2021, 17, 11–21, doi:10.3762/bjoc.17.2

• repulsion of the terminal aromatic nuclei. The steric strain releases by adopting either the P- or M-helix configuration. The helically extended π-conjugated system, axial chirality and associated with these structural peculiarities unique optical and electronic properties of helicenes have attracted

• scientific interest for decades [1][2][3][4][5][6][7][8][9][10][11]. Compared to other planar π-conjugated systems, helicenes are more thermally stable and soluble in common organic solvents [9]. This fact together with the exceptionally high values of specific optical rotation and strong circular dichroism

Synthesis and characterization of S,N-heterotetracenes

• Astrid Vogt,
• Florian Henne,
• Christoph Wetzel,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2020, 16, 2636–2644, doi:10.3762/bjoc.16.214

• reaction; optoelectronic properties; S,N-heteroacene; structure–property relationship; Introduction Thienoacenes and related S,N-heteroacenes have been developed to important π-conjugated systems mainly for application as p-type semiconductor in organic electronic devices with excellent results [1][2][3

• –property relationships showing the influence of the number and sequence of pyrrole rings. The highly planar π-conjugated systems revealed interesting structural features such as nearly complete bond length equalization and S–S and S–π dipolar interactions in the solid state. Due to tunable optoelectronic

• of azide precursors, and a Cadogan cyclization of nitro-substituted precursors were applied to prepare various unknown derivatives. These represent novel core molecules, which by further derivatisation, for example with terminal acceptor groups, would lead to interesting π-conjugated materials for

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• -assembly, and optical properties of bowl-shaped π-conjugated systems [5][6][7][8][9]. The synthesis of π-bowls is an extremely challenging job due to the presence of unusual strain in these types of molecules, therefore, the first synthetic breakthrough in this arena came into the picture in the late

• ]. In another study, the same group has also reported a series of both C3-symmetric as well as unsymmetric diastereomeric π-conjugated bowl-shaped molecules 37a–f in good to quantitative yields (Scheme 6) [34][35]. These π-conjugated systems were assembled by treating sumanene (2) with different

• corresponding trimethylsumanene 28 by means of nucleophilic oxidation using NaHMDS in the presence of molecular oxygen in DMF as the solvent (Scheme 8). It has been noticed from the literature that the directly linked π-conjugated systems act as promising electron-accepting materials because of their high LUMO

Development of fluorinated benzils and bisbenzils as room-temperature phosphorescent molecules

• Shigeyuki Yamada,
• Takuya Higashida,
• Yizhou Wang,
• Masato Morita,
• Takuya Hosokai,
• Kaveendra Maduwantha,
• Kaveenga Rasika Koswattage and
• Tsutomu Konno

Beilstein J. Org. Chem. 2020, 16, 1154–1162, doi:10.3762/bjoc.16.102

• materials, and biosensors in biomedical diagnostics [1][2][3][4] and as organic light-emitting diodes in the technological field [5][6][7][8]. Among the organic light-emitting molecules developed thus far, extended π-conjugated compounds (e.g., pyrenes and perylenes) emit fluorescence, which is a radiative

• deactivation process from the lowest singlet (S1) excited state to the ground (S0) state [9]. Interestingly, for such π-conjugated molecules, suitable structural modifications can switch the radiative S1→S0 process to another radiative deactivation process from the triplet (T1) excited state to S0 via an S1→T1

Synthesis and properties of tetrathiafulvalenes bearing 6-aryl-1,4-dithiafulvenes

• Aya Yoshimura,
• Hitoshi Kimura,
• Kohei Kagawa,
• Mayuka Yoshioka,
• Toshiki Itou,
• Dhananjayan Vasu,
• Takashi Shirahata,
• Hideki Yorimitsu and
• Yohji Misaki

Beilstein J. Org. Chem. 2020, 16, 974–981, doi:10.3762/bjoc.16.86

• bearing 1,3-dithiol-2-ylidenes took place efficiently to produce the corresponding π-conjugated molecules. We also succeeded in the estimation of the oxidation potentials and number of electrons involved in each oxidation step of the obtained compounds by digital simulations. Keywords: cross-conjugated

Pd-catalyzed asymmetric Suzuki–Miyaura coupling reactions for the synthesis of chiral biaryl compounds with a large steric substituent at the 2-position

• Yongsu Li,
• Bendu Pan,
• Xuefeng He,
• Wang Xia,
• Yaqi Zhang,
• Hao Liang,
• Chitreddy V. Subba Reddy,
• Rihui Cao and
• Liqin Qiu

Beilstein J. Org. Chem. 2020, 16, 966–973, doi:10.3762/bjoc.16.85

• enantioselectivities (up to 88% ee) under mild conditions. The chiral-bridged biphenyl monophosphine ligands developed by our group exhibit significant superiority to the naphthyl counterpart MOP in both reactivity and enantioselectivity control. The large steric hindrance from π-conjugated ortho-substituents of the

• from π-conjugated ortho-substituents of the bromobenzenes is also important. In addition, coupling of 2-bromo-3-nitrotoluene with 4-substituted or unsubstituted 1-naphthaleneboronic acids provided the corresponding products in high yields with good ee values (5g, 98% yield, 75% ee; 5h, 97% yield, 83

• % ee; 5i, 98% yield, 85% ee) [39][62]. All these results show that the large steric hindrance from π-conjugated ortho-substituents of the bromobenzenes and the O···Pd interaction work together for the acquisition of high enantioselectivity. As stated before, the replacement of naphthaleneboronic acid

Bipyrrole boomerangs via Pd-mediated tandem cyclization–oxygenation. Controlling reaction selectivity and electronic properties

• Liliia Moshniaha,
• Marika Żyła-Karwowska,
• Joanna Cybińska,
• Piotr J. Chmielewski,
• Ludovic Favereau and
• Marcin Stępień

Beilstein J. Org. Chem. 2020, 16, 895–903, doi:10.3762/bjoc.16.81

• disadvantage may be obviated by transition-metal-mediated double C–H bond activation [22][23], which is functionally equivalent to conventional oxidative coupling reactions, and has become a powerful synthetic tool with a rapidly growing scope of use [24][25][26]. However, in the field of π-conjugated

Towards triptycene functionalization and triptycene-linked porphyrin arrays

• Gemma M. Locke,
• Keith J. Flanagan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2020, 16, 763–777, doi:10.3762/bjoc.16.70

• linked which, theoretically, can cause a significant energy/charge sink. Moreover, the use of π-conjugated linkers in porphyrin arrays results in significantly altered UV–vis spectra, indicating very strong electronic coupling that causes the loss of individual unit characteristics through delocalization

Synthesis of C₇₀-fragment buckybowls bearing alkoxy substituents

• Yumi Yakiyama,
• Shota Hishikawa and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2020, 16, 681–690, doi:10.3762/bjoc.16.66

• equilibrium between the Pd(IV) intermediates through C–H bond activation. Keywords: buckybowl; C70; rearrangement through C–H bond activation; Introduction The study of buckybowls, the bowl-shaped π-conjugated aromatic hydrocarbons corresponding to the fragments of fullerenes, pioneered by the works on

• enantiomers, however, they were disordered with 50% site occupancy (Figure 2a). The POAV (π-orbital axis vector) pyramidalization angle φ [27], which is often used for quantifying the curvature of curved π-conjugated materials (Figure 3a) showed 6.5° at C1 as the minimum value, and 7.6° at C3, which is

Regioselectively α- and β-alkynylated BODIPY dyes via gold(I)-catalyzed direct C–H functionalization and their photophysical properties

• Takahide Shimada,
• Shigeki Mori,
• Masatoshi Ishida and
• Hiroyuki Furuta

Beilstein J. Org. Chem. 2020, 16, 587–595, doi:10.3762/bjoc.16.53

• ][11][12], photocatalysis [13][14][15][16], optics [17][18][19][20], and so forth. The structure of BODIPY derivatives is composed of a dipyrromethene (an oxidized form of dipyrromethane 2) and a coordinated difluoroboron moiety [21]. The rigid π-conjugated scaffold of BODIPYs demonstrates fascinating

• -tethered BODIPY derivatives serve as a substrate in the copper-catalyzed azide–alkyne cycloaddition (CuAAC) reaction, which is known as “click” reaction, allowing for a biological tissue labelling [35][36]. In addition, ethynyl-substituted BODIPYs yield unique π-conjugated BODIPY-based macrocycles by

Synthesis of triphenylene-fused phosphole oxides via C–H functionalizations

• Md. Shafiqur Rahman and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2020, 16, 524–529, doi:10.3762/bjoc.16.48

• nature as hybrids of triphenylene and benzo[b]phosphole. Keywords: C–H functionalization; fluorescence; phosphole; polycyclic aromatic hydrocarbons; triphenylene; Introduction The phosphorus-containing five-membered ring, phosphole, has attracted significant attention as a structural motif in π

• -conjugated functional molecules [1][2][3][4][5][6][7][8][9]. Its inherently unique electronic structure, along with opportunities to modify the phosphorus center and the periphery by substitution or ring fusion, have stimulated chemists to explore a structurally diverse range of phosphole derivatives with

Room-temperature Pd/Ag direct arylation enabled by a radical pathway

• Amy L. Mayhugh and
• Christine K. Luscombe

Beilstein J. Org. Chem. 2020, 16, 384–390, doi:10.3762/bjoc.16.36

• radical; visible light; Introduction π-Conjugated polymers are of significant interest as they have the potential to combine the mechanical flexibility and affordability of synthetic polymers with the optical and electronic properties of semiconductors. One of the limitations to this field’s continued

• Amy L. Mayhugh Christine K. Luscombe Department of Chemistry, University of Washington, Seattle, WA 98195, USA Department of Materials Science & Engineering, University of Washington, Seattle, WA 98195, USA 10.3762/bjoc.16.36 Abstract Direct arylation is an appealing method for preparing π

• -conjugated materials, avoiding the prefunctionalization required for traditional cross-coupling methods. A major effort in organic electronic materials development is improving the environmental and economic impact of production; direct arylation polymerization (DArP) is an effective method to achieve these

Synthesis of aryl-substituted thieno[3,2-b]thiophene derivatives and their use for N,S-heterotetracene construction

• Nadezhda S. Demina,
• Nikita A. Kazin,
• Nikolay A. Rasputin,
• Roman A. Irgashev and
• Gennady L. Rusinov

Beilstein J. Org. Chem. 2019, 15, 2678–2683, doi:10.3762/bjoc.15.261

• the synthesis of aryl-substituted 9H-thieno[2',3':4,5]thieno[3,2-b]indoles. These π-conjugated ring-fused molecules are of interest as electron-rich subunits for further organic semiconductors development. An example of an earlier developed S,N-heterohexacene [13] and general structure of compounds

Small anion-assisted electrochemical potential splitting in a new series of bistriarylamine derivatives: organic mixed valency across a urea bridge and zwitterionization

• Keishiro Tahara,
• Tetsufumi Nakakita,
• Alyona A. Starikova,
• Takashi Ikeda,
• Masaaki Abe and
• Jun-ichi Kikuchi

Beilstein J. Org. Chem. 2019, 15, 2277–2286, doi:10.3762/bjoc.15.220

• intramolecular electron transfer phenomena and application in molecular devices [1][2][3][4][5]. The radical cations of bistriarylamine derivatives bis(NAr3) are well-known MV compounds having π-conjugated bridges (where NAr3 = triarylamine) [6][7][8][9][10][11][12][13][14][15][16][17][18]. These studies focused

• effects were previously reported for bis(NAr3) derivatives having π-conjugated bridges [8][9]. Judging from the long N···N distances (e.g., 13.16 Å for 1b+) in the DFT-optimized structure (Figure S5 in Supporting Information File 1), the through-space electrostatic interactions between the NAr3 units

• greater than that reported for its ferrocenyl counterpart (FcFc+) in the one-electron-oxidized form (HAB = 165 cm−1) [42]. In conventional π-conjugated bis(NAr3) derivatives [8], it was clearly demonstrated that electron-rich bridges increased HAB values. In the previous and present urea-bridged MV

Synthesis of a [6]rotaxane with singly threaded γ-cyclodextrins as a single stereoisomer

• Jason Yin Hei Man and
• Ho Yu Au-Yeung

Beilstein J. Org. Chem. 2019, 15, 1829–1837, doi:10.3762/bjoc.15.177

• , cyanine and azobenzene have also been reported [18][19][20][21][22][23][24]. High order oligorotaxanes with a multiple number of α- or β-CDs threaded through polymer chains have also been prepared [25][26][27][28]. The interlocked CDs have been shown to provide an interesting insulating effect to π

• -conjugated polymers [29][30][31]. On the other hand, γ-CD is relatively less employed in the synthesis of mechanically interlocked molecules despite of its ability to form interesting 1:2 inclusion complexes, and there are only few examples of rotaxane and catenane featuring γ-CD as an interlocked macrocycle

Norbornadiene-functionalized triazatriangulenium and trioxatriangulenium platforms

• Roland Löw,
• Talina Rusch,
• Tobias Moje,
• Fynn Röhricht,
• Olaf M. Magnussen and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1815–1821, doi:10.3762/bjoc.15.175

• monolayers. A linear, π-conjugated spacer (e.g., an ethynyl unit) is attached to the central carbon atom and the functional molecule is mounted on top. This architecture allows investigating molecules on surfaces under controlled conditions. The size of the platforms determines the intermolecular distances

Synthesis, photophysical and electrochemical properties of pyridine, pyrazine and triazine-based (D–π–)₂A fluorescent dyes

• Keiichi Imato,
• Toshiaki Enoki,
• Koji Uenaka and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2019, 15, 1712–1721, doi:10.3762/bjoc.15.167

• Keiichi Imato Toshiaki Enoki Koji Uenaka Yousuke Ooyama Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527, Japan 10.3762/bjoc.15.167 Abstract The donor–acceptor–π-conjugated (D–π–)2A fluorescent dyes OUY-2, OUK-2

• and OUJ-2 with two (diphenylamino)carbazole thiophene units as D (electron-donating group)–π (π-conjugated bridge) moiety and a pyridine, pyrazine or triazine ring as electron-withdrawing group (electron-accepting group, A) have been designed and synthesized. The photophysical and electrochemical

• lowering of the LUMO energy level are dependent on the electron-withdrawing ability of the azine ring, which increases in the order of OUY-2 < OUK-2 < OUJ-2. Keywords: D–π–A structure; fluorescent dyes; pyrazine; pyridine; triazine; Introduction Donor–π-conjugated–acceptor (D–π–A) dyes are constructed of