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

• electroactive materials [52][53][54]. Carbazole-based [6]helicenes [42] and [7]helicenes [50] showed deep blue electroluminescence and have been investigated in OLED devices. Some carbazole-based [5]- and [6]helicenes have been used as visible light photoinitiators for cationic and radical polymerization [41

Synthesis and properties of quinazoline-based versatile exciplex-forming compounds

• Rasa Keruckiene,
• Simona Vekteryte,
• Ervinas Urbonas,
• Matas Guzauskas,
• Eigirdas Skuodis,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101

• donor 4,4′,4″-tris[3-methylphenyl(phenyl)amino]triphenylamine. A white OLED based on these versatile exciplex systems with a relatively high maximum brightness of 3030 cd/m2 and an external quantum efficiency of 0.5% was fabricated. Keywords: carbazole; dimethyldihydroacridine; exciplex; phenothiazine

• photoluminescence and electroluminescence based on blue emissive quinazoline derivatives obtained through controlled acid protonation were employed in a single-layered white OLED with EQEs of 1.4% and 3% [9]. These reports proved that by using an asymmetric quinazoline acceptor, highly efficient TADF materials for

• -doped OLED with three light-emitting layers comprising m-MTDATA:1:PO-T2T was fabricated (Figure 7c). The structure of the device was as follows: HAT-CN (10 nm)/NPB (48 nm)/m-MTDATA (16 nm)/compound 1 (20 nm)/PO-T2T (16 nm)/TSPO1 (4 nm)/TBPi (36 nm). In this device architecture, the common hole/electron

Aryl-substituted acridanes as hosts for TADF-based OLEDs

• Naveen Masimukku,
• Dalius Gudeika,
• Oleksandr Bezvikonnyi,
• Ihor Syvorotka,
• Rasa Keruckiene,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 989–1000, doi:10.3762/bjoc.16.88

• demonstrated maximum external quantum efficiencies up to 3.2%. Keywords: acridan; hole mobility; host; OLED; thermally activated delayed fluorescence; Introduction Organic light emitting diodes (OLEDs) are perfect candidates for multicolor displays and for next generation energy saving large area-lighting

• splitting (∆EST) between the lowest singlet and triplet excited states [5]. Various TADF derivatives have been developed with the aim to obtain highly efficient OLEDs by combining diverse donor and electron-acceptor moieties [6][7]. To successfully exploit TADF emitters in OLED structures, appropriate hosts

• are required [8]. Since the selection of suitable hosts is very important for achieving high OLED efficiencies, there was considerable interest in host compounds for TADF emitters in recent years [9][10]. The host compounds for TADF-based OLEDs must match a number of censorious requests. For example

Synthesis of ([1,2,4]triazolo[4,3-a]pyridin-3-ylmethyl)phosphonates and their benzo derivatives via 5-exo-dig cyclization

• Aleksandr S. Krylov,
• Artem A. Petrosian,
• Julia L. Piterskaya,
• Nataly I. Svintsitskaya and
• Albina V. Dogadina

Beilstein J. Org. Chem. 2019, 15, 1563–1568, doi:10.3762/bjoc.15.159

• number of drugs and [1,2,4]triazolo[4,3-a]pyridines were shown to have herbicidal [5][6], antifungal [7], neuroprotective [8][9] and antibacterial activity [10]. In addition, [1,2,4]triazolopyridine has been used as electron-acceptor unit in the synthesis of organic light emitting diodes (OLED) [11]. 2

Recent advances in materials for organic light emitting diodes

• Eli Zysman-Colman

Beilstein J. Org. Chem. 2018, 14, 1944–1945, doi:10.3762/bjoc.14.168

• molecular design approach for orange-emitting TADF molecules employing a fluorenone acceptor [5]. In the full research paper by Feng-Ming Xie et al., they disclose two bipolar, high-energy phenothiazine-5,5-dioxide-based host materials conceived to be used for deep blue OLED devices [6]. The articles in

Recent advances in phosphorescent platinum complexes for organic light-emitting diodes

• Cristina Cebrián and
• Matteo Mauro

Beilstein J. Org. Chem. 2018, 14, 1459–1481, doi:10.3762/bjoc.14.124

• ; electroluminescence; OLED; phosphorescence; platinum complexes; Introduction Photoactive TMCs have attracted enormous attention in the last two decades because of their peculiar photophysical and rich redox properties, which make them appealing from both fundamental research and technological applications points of

• an efficient (external quantum efficiency, EQE, ca. 4%) OLED device [10]. Since that pioneering work, an impressive amount of research effort has been devoted in the last two decades to seeking for TMCs that display better device performances. In this respect, iridium(III) and platinum(II

• doped films, OLED devices were fabricated showing remarkable efficiency attaining EQE of 21.5% at a luminance of 1029 cd m−2 with small roll-off [21]. These performances are the best reported so far for such a practical luminance. Systems based on bidentate ligands In the past, the most common synthetic

D–A–D-type orange-light emitting thermally activated delayed fluorescence (TADF) materials based on a fluorenone unit: simulation, photoluminescence and electroluminescence studies

• Lin Gan,
• Xianglong Li,
• Xinyi Cai,
• Kunkun Liu,
• Wei Li and
• Shi-Jian Su

Beilstein J. Org. Chem. 2018, 14, 672–681, doi:10.3762/bjoc.14.55

• -emitting diode (OLED); thermally activated delayed fluorescence; Introduction Since multilayered OLEDs were first reported by Tang in 1987 [1], organic light-emitting diodes (OLEDs) have been a research focus due to their applications in display devices and general lighting. The efficiency of OLEDs was

• spectrometry. Both of them show TADF behavior with orange emission color according to the photoluminescence spectra and time-resolved transient photoluminescence decay measurement. EQEs of 2.9% and 8.9% were achieved for the OLED devices based on 1 and 2, respectively, which are higher than the theoretical

• τTADF not only signifies efficient utilization of singlet excitons, but is also advantageous in reducing the triplet exciton concentration and efficiency roll-off in the OLED devices. Finally, electroluminescent properties of 1 and 2 were characterized in a device structure of ITO/TAPC (25 nm)/1 wt

Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)

• Thanh-Tuân Bui,
• Fabrice Goubard,
• Malika Ibrahim-Ouali,
• Didier Gigmes and
• Frédéric Dumur

Beilstein J. Org. Chem. 2018, 14, 282–308, doi:10.3762/bjoc.14.18

• popularized by Chihaya Adachi since 2012. In this review, we proposed to focus on the recent advances in the molecular design of blue TADF emitters for OLEDs during the last few years. Keywords: blue; electroluminescence; emitter; OLED; TADF; Introduction Since the pioneering works of Tang and VanSlyke in

• - and T23-based devices, respectively. As anticipated, a lower color purity was obtained for T21-based devices resulting from its lower oxidation potential. Recently, a significant enhancement of blue OLED performances was obtained by replacing the triazine acceptor by a 2,4,6-triphenylpyrimidine unit

• lifetimes for the delayed decay component varied from 1.9 to 19 μs. All compounds were tested in OLED and all devices exhibited a relatively low turn-on voltage (≈2.5 V) and a low operation voltage (≈3.5–4 V for a brightness of 100 cd·m−2). Devices using high-PLQY emitters (PLQY = 90–100%) exhibited rather

Rh(II)-mediated domino [4 + 1]-annulation of α-cyanothioacetamides using diazoesters: A new entry for the synthesis of multisubstituted thiophenes

• Jury J. Medvedev,
• Ilya V. Efimov,
• Yuri M. Shafran,
• Vitaliy V. Suslonov,
• Vasiliy A. Bakulev and
• Valerij A. Nikolaev

Beilstein J. Org. Chem. 2017, 13, 2569–2576, doi:10.3762/bjoc.13.253

• photosensitivity and hence could be used in OLED devices [68]. Also these compounds display high nucleophilicity in reactions with electrophiles which are often accompanied by a variety of thiophene heterocycle transformations, and hence could be successfully used for their further functionalization [69

Structure–property relationships and third-order nonlinearities in diketopyrrolopyrrole based D–π–A–π–D molecules

• Jan Podlesný,
• Lenka Dokládalová,
• Oldřich Pytela,
• Adam Urbanec,
• Milan Klikar,
• Numan Almonasy,
• Tomáš Mikysek,
• Jaroslav Jedryka,
• Iwan V. Kityk and
• Filip Bureš

Beilstein J. Org. Chem. 2017, 13, 2374–2384, doi:10.3762/bjoc.13.235

• -emitting diodes (OLED), fluorophores, probes for ion sensing, functional polymers, and more recently also chromophores with nonlinear optical (NLO) activity. The latter property is mostly dictated by their conjugated character, electron-accepting behavior of the DPP scaffold, strong emissive character, and

Enzymatic synthesis of glycosides: from natural O- and N-glycosides to rare C- and S-glycosides

• Jihen Ati,
• Pierre Lafite and
• Richard Daniellou

Beilstein J. Org. Chem. 2017, 13, 1857–1865, doi:10.3762/bjoc.13.180

• acceptor. UGT74B1, involved in glucosinolate biosynthesis (see supra), was one of these 17 enzymes. Other studies have identified S-GT activities when assaying the catalytic promiscuity of O-GT with a wide range of aglycone acceptors (Figure 3). OleD from Streptomyces antibioticus has been the first

Scalable synthesis of 5,11-diethynylated indeno[1,2-b]fluorene-6,12-diones and exploration of their solid state packing

• Bradley D. Rose,
• Peter J. Santa Maria,
• Aaron G. Fix,
• Chris L. Vonnegut,
• Lev N. Zakharov,
• Sean R. Parkin and
• Michael M. Haley

Beilstein J. Org. Chem. 2014, 10, 2122–2130, doi:10.3762/bjoc.10.219

• emitting devices (OLED) [7]. For such devices to operate properly, these must include materials that conduct holes (electron donating) and conduct electrons (electron accepting) [8]. While there are many systems that display high hole mobilities, there are far fewer that exhibit high electron mobilities

Crystal design using multipolar electrostatic interactions: A concept study for organic electronics

• Peer Kirsch,
• Qiong Tong and
• Harald Untenecker

Beilstein J. Org. Chem. 2013, 9, 2367–2373, doi:10.3762/bjoc.9.272

• techniques [3]. High charge carrier mobilities are a particularly critical prerequisite for application in backplanes for OLED displays. The highest charge carrier mobilities in organic compounds have so far been reported for single crystals of small molecules [4], the “classics” among them being acenes such

Studies on the photodegradation of red, green and blue phosphorescent OLED emitters

• Susanna Schmidbauer,
• Andreas Hohenleutner and
• Burkhard König

Beilstein J. Org. Chem. 2013, 9, 2088–2096, doi:10.3762/bjoc.9.245

• . The observations from this study may help to better understand degradation processes occurring during the handling of the materials, but also during device processing and operation. Keywords: iridium complexes; OLED; photoinduced degradation; phosphorescent emitters; Introduction For applications

Imidazole as a parent π-conjugated backbone in charge-transfer chromophores

• Jiří Kulhánek and
• Filip Bureš

Beilstein J. Org. Chem. 2012, 8, 25–49, doi:10.3762/bjoc.8.4

• robustness, possibility for further modification, and facile property tuning. Hence, heteroaromatic push–pull chromophores have been targeted and investigated as active components of optoelectronic devices, organic light-emitting diodes (OLED), photovoltaic cells, semiconductors, switches, data-storage

• electrodes to facilitate the electron or hole injection and transfer in OLED devices. 2,5-Bis(benzimidazol-2-yl)pyrazine derivatives 70 (BBIP), with improved solubility through N,N’-dialkylation, exhibited high fluorescence intensity even in protic solvents, as well as interesting solvatochromic properties

Novel carbazole–pyridine copolymers by an economical method: synthesis, spectroscopic and thermochemical studies

• Aamer Saeed,
• Madiha Irfan and
• Shahid Ameen Samra

Beilstein J. Org. Chem. 2011, 7, 638–647, doi:10.3762/bjoc.7.75

• . The weight average molecular masses (Mw) of the polymers were estimated by the laser light scattering (LLS) technique. Keywords: carbazole–pyridine copolymers; fluorescent materials; organic light emitting diode (OLED); photoluminescence spectra; UV spectra; Introduction An immense research effort

• for employing organic materials as LEDs [7] and carbazole containing polymers are the most studied group amongst the different polymers intended for OLED applications [8][9][10][11][12][13][14][15]. Carbazole containing polymers exhibit excellent electron-donating properties together with intense

Donor-acceptor substituted phenylethynyltriphenylenes – excited state intramolecular charge transfer, solvatochromic absorption and fluorescence emission

• Ritesh Nandy and
• Sethuraman Sankararaman

Beilstein J. Org. Chem. 2010, 6, 992–1001, doi:10.3762/bjoc.6.112

• reports on the extension of conjugation of the triphenylene chromophore have appeared. 2,3,6,7,10,11-Hexakis(ethynyl)triphenylene derivatives have been used in photonics as organic light emitting diode (OLED) materials [40][41][42]. Therefore, it is worthwhile to tune the fluorescence emission of the

Functional properties of metallomesogens modulated by molecular and supramolecular exotic arrangements

• Alessandra Crispini,
• Mauro Ghedini and
• Daniela Pucci

Beilstein J. Org. Chem. 2009, 5, No. 54, doi:10.3762/bjoc.5.54

• organized into columns, the broad thermal stability and the luminescence in the red region of the visible spectrum make this new Pd(II) complex a very intriguing candidate for applications in OLED devices. A further class of ortho-palladated complexes has been obtained starting from the 2-phenylquinoline, a

• of tunability, depending on the π-donor capacity of the X ligands. Zinc(II) complexes are widely applied in OLED technology for their light emitting efficiency, high thermal and redox stability, and tunable electronic properties [53][54][55]. Hence the design of Zn(II) complexes showing at the same

A stable enol from a 6-substituted benzanthrone and its unexpected behaviour under acidic conditions

• Marc Debeaux,
• Kai Brandhorst,
• Peter G. Jones,
• Henning Hopf,
• Jörg Grunenberg,
• Wolfgang Kowalsky and
• Hans-Hermann Johannes

Beilstein J. Org. Chem. 2009, 5, No. 31, doi:10.3762/bjoc.5.31

• derivatives have been shown to be efficient emitters for OLED applications [2]. In these devices, the benzanthrone moiety acts as an electron accepting group, whereas the diarylamine group functions as an electron donor. The reaction of 1 with various organometallic reagents was studied by Allen in the 1970s

Convenient methods for preparing π-conjugated linkers as building blocks for modular chemistry

• Jiří Kulhánek,
• Filip Bureš and
• Miroslav Ludwig

Beilstein J. Org. Chem. 2009, 5, No. 11, doi:10.3762/bjoc.5.11

• ], organic light-emitting diodes (OLED) [9] or functional polymers [10][11][12][13]. A typical push-pull chromophore consists of a polar A-π-D system with a planar π-system end-capped by a strong electron donor (D) and a strong electron acceptor (A). The π-conjugated system ensuring charge-transfer (CT

Highly brominated anthracenes as precursors for the convenient synthesis of 2,9,10-trisubstituted anthracene derivatives

• Osman Cakmak,
• Leyla Aydogan,
• Kiymet Berkil,
• Ilhami Gulcin and
• Orhan Buyukgungor

Beilstein J. Org. Chem. 2008, 4, No. 50, doi:10.3762/bjoc.4.50

• diode (OLED) were synthesized from the corresponding bromo derivatives by substitution [19][20][21][22][23]. Recently we succeeded in the bromination of anthracene to give hexabromides 3 and 4 which were used in the selective and specific preparation of anthracene oxides and anthracene derivatives