On the photoluminescence in triarylmethyl-centered mono-, di-, and multiradicals

• Daniel Straub,
• Markus Gross,
• Mona E. Arnold,
• Julia Zolg and
• Alexander J. C. Kuehne

Beilstein J. Org. Chem. 2025, 21, 964–998, doi:10.3762/bjoc.21.80

• effect is not due to the changed electron accepting strength, TTM radicals with additional chlorination only at the phenyl ring, to which the donor moiety is connected have been synthesized. Also here, a strong increase of the ϕ compared to the donor-functionalized TTM radicals has been observed (see

4-(1-Methylamino)ethylidene-1,5-disubstituted pyrrolidine-2,3-diones: synthesis, anti-inflammatory effect and in silico approaches

• Nguyen Tran Nguyen,
• Vo Viet Dai,
• Luc Van Meervelt,
• Do Thi Thao and
• Nguyen Minh Thong

Beilstein J. Org. Chem. 2025, 21, 817–829, doi:10.3762/bjoc.21.65

• (3.032 eV) and 5e (2.694 eV) emphasize their strong electron-accepting capabilities, while the high IE of 5c (6.429 eV) indicates its resistance to electron donation. These findings suggest that compounds 5c and 5e are highly reactive and suitable for applications requiring active electron transfer

Synthesis, characterization, and photophysical properties of novel 9‑phenyl-9-phosphafluorene oxide derivatives

• Shuxian Qiu,
• Duan Dong,
• Jiahui Li,
• Huiting Wen,
• Jinpeng Li,
• Yu Yang,
• Shengxian Zhai and
• Xingyuan Gao

Beilstein J. Org. Chem. 2024, 20, 3299–3305, doi:10.3762/bjoc.20.274

• recent years, and they are mostly based on purely organic electron donor−electron acceptor (D−A) or D−A−D systems with significant intramolecular charge transfer interactions for frontier molecular orbital separation [28][29][30]. Due to the electron-accepting properties, PhFlOP can clearly act as an

Synthesis of indano[60]fullerene thioketone and its application in organic solar cells

• Yong-Chang Zhai,
• Shimon Oiwa,
• Shinobu Aoyagi,
• Shohei Ohno,
• Tsubasa Mikie,
• Jun-Zhuo Wang,
• Hirofumi Amada,
• Koki Yamanaka,
• Kazuhira Miwa,
• Naoyuki Imai,
• Takeshi Igarashi,
• Itaru Osaka and
• Yutaka Matsuo

Beilstein J. Org. Chem. 2024, 20, 1270–1277, doi:10.3762/bjoc.20.109

• bond length may have caused the higher reactivity and lower degradation temperature of t-Bu-FIDS compared with t-Bu-FIDO. Electron-accepting ability is one of the most important properties for fullerene derivatives, and it is typically described in terms of the energy level of the lowest unoccupied

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

• Tural N. Akhmedov,
• Ajeet Kumar,
• Daken J. Starkenburg,
• Kyle J. Chesney,
• Khalil A. Abboud,
• Novruz G. Akhmedov,
• Jiangeng Xue and
• Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

• . reported the synthesis, electronic characteristics, and liquid-crystalline properties of several electron-accepting acenes, including 1,4-dihydropyrazinoquinoxalinediones (Figure 1b). The incorporation of strong hydrogen-bonding interactions facilitated the formation of a highly ordered liquid-crystalline

• of electron-accepting azaacene derivatives as liquid-crystalline materials by Takeda et al. (b) [24]. Transformation of Yamashita’s DCPQs to H-bonding capable DPQD derivatives discussed in this work (c) [25]. TGA of 1a–6a (a) and 1b–7b (b) obtained at 10 °C/min under nitrogen. Absorption spectra (20

Organic electron transport materials

• Joseph Cameron and
• Peter J. Skabara

Beilstein J. Org. Chem. 2024, 20, 672–674, doi:10.3762/bjoc.20.60

• react with acceptors to produce reducing radical species, capable of reducing organic electron transport materials with a low electron affinity [4][5]. It is not only in modifying the molecular structure to improve the electron accepting ability that there is innovation in new organic electron transport

Enhanced reactivity of Li⁺@C₆₀ toward thermal [2 + 2] cycloaddition by encapsulated Li⁺ Lewis acid

• Hiroshi Ueno,
• Yu Yamazaki,
• Hiroshi Okada,
• Fuminori Misaizu,
• Ken Kokubo and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2024, 20, 653–660, doi:10.3762/bjoc.20.58

• yield of multiadducts compared to previously reported functionalizations of Li+@C60. The reason can be explained by the difference in electron-accepting ability between the monoadduct and pristine Li+@C60 investigated by cyclic voltammetry (Figure 5). Both products exhibited reversible first and second

Photochromic derivatives of indigo: historical overview of development, challenges and applications

• Gökhan Kaplan,
• Zeynel Seferoğlu and
• Daria V. Berdnikova

Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23

• absorption band and increases its intensity, while the presence of the EA (electron-accepting) substituents in these positions leads to a hypsochromic shift (Figure 5). On the contrary, the introduction of the ED substituents at the para (6,6')- or ortho (4,4')-positions to the electron-withdrawing C=O group

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• chromophores, wherein both electron-donating and electron-accepting substituents are incorporated into a π-electron-conjugated system, exhibit exceptional optical and electronic properties. They hold significant promise for applications in diverse fields, particularly materials science (specifically in

• cyclopentadiene moieties. TCBD 4, obtained through the [2 + 2] CA–RE reaction, continues to function as an electron-accepting alkene, as shown in Scheme 4. Subsequent [2 + 2] CA–RE reactions involving electron-rich alkynes yield tetracyano-1,3,5-hexatrienes (TCHTs). These reactions occur seamlessly in a one-pot

• , exhibiting enhanced electron-accepting capabilities, reacts with 1, it displays a more intricate reaction profile compared with that of 4 (Scheme 5). In addition to pentacyano-1,3-5-hexatriene (PCHT) compound 7, compounds 8 and 9 are generated [102]. This reaction is notably influenced by the different

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

• Christina Schøttler,
• Kasper Lund-Rasmussen,
• Line Broløs,
• Philip Vinterberg,
• Ema Bazikova,
• Viktor B. R. Pedersen and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

• other end of the IF core with electron-accepting moieties. An overview of general motifs targeted in this work is shown in Figure 1. Results and Discussion Synthesis The synthetic building blocks 1–8 used in this work are shown in Figure 2. The dione 1 and the ketones 4 and 6 were synthesized according

• ) expanding to ca. 680 nm. UV–vis absorption spectra of compounds 22, 23, 26, and 27 are depicted in Figure 5. By comparing donor–acceptor chromophores 22 and 23, it is observed that the RA moiety of DTF-IF-RA scaffold 23 induces a significant redshift, presumably due to the stronger electron-accepting

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• values of Ered,onset are comparable with those of recently published compounds containing a dicyanopyridyl moiety as a central electron-accepting core [7]. In case of oxidation potentials (0.96 to 1.04 V) there is only a slight effect of the extended conjugation between the dicyanopyridyl moieties. The

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• . Photovoltaic performance of some of the reported materials is tabulated in Table 2. Quinoxalines as auxiliary acceptors and π-bridges Qx derivatives are highly attractive auxiliary acceptor and bridging materials for DSSCs. Their strong electron-accepting ability enables efficient electron injection and charge

• (PTFTs) with Qx54 copolymer showed ambipolar characteristics, while the PTFTs with Qx55 copolymer exhibited only n-type charge transport [57]. Kamble et al. designed and synthesized a series of eight new indolo[2,3-b]naphtho[2,3-f]quinoxaline derivatives (Qx56) by incorporating an electron-accepting

• in emission properties through mechanical stimulation offers exciting possibilities for optomechanical applications [68]. Another notable strategy, performed by Gupta and co-workers, involves fine-tuning of the electron accepting tendency of quinoxaline by incorporating various groups with different

A deep-red fluorophore based on naphthothiadiazole as emitter with hybridized local and charge transfer and ambipolar transporting properties for electroluminescent devices

• Suangsiri Arunlimsawat,
• Patteera Funchien,
• Pongsakorn Chasing,
• Atthapon Saenubol,
• Taweesak Sudyoadsuk and
• Vinich Promarak

Beilstein J. Org. Chem. 2023, 19, 1664–1676, doi:10.3762/bjoc.19.122

• device. Conclusion In summary, a new D–A–D-type fluorophore as a deep-red emitter has been designed and synthesized by exploiting a strong electron-accepting naphtho[2,3-c][1,2,5]thiadiazole (Nz) as A unit and N-(4-(1,2,2-triphenylvinyl)phenyl)carbazole as D unit. The integration of 4-(1,2,2

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• the energy ordering of the transient species involved in the TADF photophysical process, the electron-donating strength of the PTZ moiety is lowered by oxidation of the sulfur atom to the corresponding sulfoxide. Conversely, the electron-accepting capability of the NI unit is varied by introducing

• ability of the PTZ unit are unchanged, but the electron-accepting ability of the NI part is changed by introducing different aryl substituents at the nitrogen of the NI unit. We found the magnitude of the long-lived components of the TADF emitters is changed (Figure 4a–d). Interestingly, the dyads with

Synthesis, structure, and properties of switchable cross-conjugated 1,4-diaryl-1,3-butadiynes based on 1,8-bis(dimethylamino)naphthalene

• Semyon V. Tsybulin,
• Ekaterina A. Filatova,
• Alexander F. Pozharskii,
• Valery A. Ozeryanskii and
• Anna V. Gulevskaya

Beilstein J. Org. Chem. 2023, 19, 674–686, doi:10.3762/bjoc.19.49

• -space charge transfer (CT) in the rod-like donor–acceptor molecules showed that adding a stronger electron-donating group does not systematically induce an enhancement of the CT if a strong electron-accepting moiety is used, the latter tending to extract the electron from the conjugated chains rather

A novel spirocyclic scaffold accessed via tandem Claisen rearrangement/intramolecular oxa-Michael addition

• Anastasia Vepreva,
• Alexander Yanovich,
• Dmitry Dar’in,
• Grigory Kantin,
• Alexander Bunev and
• Mikhail Krasavin

Beilstein J. Org. Chem. 2022, 18, 1649–1655, doi:10.3762/bjoc.18.177

• crystallography. In all other cases, only the pure syn diastereomer was isolated and characterized. The yields of spirocyclic products were generally modest to good over two steps. An electron-accepting group in the benzylidene portion (5j) or an N-benzyl substitution in the starting material (5g) lowered the

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

• to poor solubility as a consequence of strong π–π interactions between the planar molecules [4]. Thus, attaching solubilising alkyl chains is necessary [5]. A common way to further decrease the HOMO–LUMO gap is attaching electron-donating and electron-accepting groups. Electron-rich units raise the

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

• fluorescent materials containing Lewis basic nitrogen heterocycles are more likely to provide the feasible band gap modulation. The essence of such phenomenon originates from Lewis acid–base coordination and adducts, which highly depends on the electron-accepting property of the Lewis acids. This

• spectral red-shift of protonated conjugated polymers depended greatly on the strength of the Lewis acid (Figure 3a) [26]. Wang et al. modulated the electron-accepting strength of intramolecular charge transfer molecules by using different acids and obtained four distinctly different solid-state emission

Mechanochemical halogenation of unsymmetrically substituted azobenzenes

• Dajana Barišić,
• Mario Pajić,
• Ivan Halasz,
• Darko Babić and
• Manda Ćurić

Beilstein J. Org. Chem. 2022, 18, 680–687, doi:10.3762/bjoc.18.69

• Information File 1), in the case of NBS in the order: L3 > L4 > L5 >> L2 (Figures S3–S6 in Supporting Information File 1), and in the case of NIS in the order: L4 >> L5 for the succinimide products (Figure S7 in Supporting Information File 1). The presence of an electron-accepting substituent (NO2) at the

• azobenzenes with electron-donating substituents by electrophilic activation with NXS. Halogenation of azobenzenes with electron-accepting substituents Using the optimal parameters for the mechanochemical bromination and iodination of L1 [51], we investigated the halogenation of azobenzene substrates with

• electron-accepting substituents at the para position relative to the azo group: 4-chloroazobenzene (L6), 4-bromoazobenzene (L7), and 4-iodoazobenzene (L8) (Scheme 2 and Table 2). The synthetic protocols included milling the mixture of Ln/NXS/TsOH 1:1.2:0.5 equiv, 5 mol % Pd(OAc)2 precatalyst, and 15 µL

Substituent effect on TADF properties of 2-modified 4,6-bis(3,6-di-tert-butyl-9-carbazolyl)-5-methylpyrimidines

• Irina Fiodorova,
• Tomas Serevičius,
• Rokas Skaisgiris,
• Saulius Juršėnas and
• Sigitas Tumkevicius

Beilstein J. Org. Chem. 2022, 18, 497–507, doi:10.3762/bjoc.18.52

• modified with various substituents in position 2 of the pyrimidine ring (Figure 1). For comparison, analysis of the TADF properties of a similar pyrimidine–carbazole emitter tCbz-mPYR is also included in this paper [29]. To enhance the electron-accepting character of the pyrimidine moiety some electron

Synthesis of phenanthridines via a novel photochemically-mediated cyclization and application to the synthesis of triphaeridine

• Songeziwe Ntsimango,
• Kennedy J. Ngwira,
• Moira L. Bode and
• Charles B. de Koning

Beilstein J. Org. Chem. 2021, 17, 2340–2347, doi:10.3762/bjoc.17.152

• the synthesis of the simple phenanthridine natural product trisphaeridine (3). Results and Discussion To investigate the scope and limitations of the reaction we initially opted to prepare a number of biaryl substrates possessing one aromatic electron accepting ring possessing a variety of methoxy

Ring-closing metathesis of prochiral oxaenediynes to racemic 4-alkenyl-2-alkynyl-3,6-dihydro-2H-pyrans

• Viola Kolaříková,
• Markéta Rybáčková,
• Martin Svoboda and
• Jaroslav Kvíčala

Beilstein J. Org. Chem. 2020, 16, 2757–2768, doi:10.3762/bjoc.16.226

• rings, as described in reference [23], was not observed in our cases. The absence of ethene resulted in a significant decrease of the yield, which gradually decreased from R = H (2a) to R = Pr (2d). Further, the reaction was not sensitive to the presence of electron-accepting groups (R = COOMe, 2e) at

Styryl-based new organic chromophores bearing free amino and azomethine groups: synthesis, photophysical, NLO, and thermal properties

• Anka Utama Putra,
• Deniz Çakmaz,
• Nurgül Seferoğlu,
• Alberto Barsella and
• Zeynel Seferoğlu

Beilstein J. Org. Chem. 2020, 16, 2282–2296, doi:10.3762/bjoc.16.189

• electron-accepting group coupled with various donors connected via a π-conjugation bridge [31][32][33]. Such dyes offer good NLO characteristics when compared to Disperse Red 1 as well as remarkable thermal stabilities with dissociation temperatures up to 300 °C [31][32]. Schiff bases containing an

• dyes containing a morpholinyl substituent (6 and 11) showed the least one. In addition, dyes 7 and 12 bear a proton-sensitive and electron-accepting pyridin-2-yl group and therefore, the absorption maxima for dyes 7 and 12 were lower than the maximum absorption wavelengths of the other dyes. The

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

• 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

Natural dolomitic limestone-catalyzed synthesis of benzimidazoles, dihydropyrimidinones, and highly substituted pyridines under ultrasound irradiation

• Kumar Godugu,
• Venkata Divya Sri Yadala,
• Mohammad Khaja Mohinuddin Pinjari,
• Trivikram Reddy Gundala,
• Lakshmi Reddy Sanapareddy and
• Chinna Gangi Reddy Nallagondu

Beilstein J. Org. Chem. 2020, 16, 1881–1900, doi:10.3762/bjoc.16.156

• groups, such as electron-donating groups (4-Me: 2b, 4-OMe: 2e, and 3,4,5-trimethoxy: 2g), an electron-accepting group (4-NO2: 2l), and halogen atoms (4-F: 2m, 4-Cl: 2n, and 3-Br: 2s), respectively, at different positions on the aromatic ring displayed a good reactivity with malononitrile (8) and

• ), 3,4-dimethoxy (2f), 3-OH (2r), and 2-OH (2h), respectively, at different positions on the ring reacted well with ethyl acetoacetate (4) and urea (5) to produce the products, 7b–f in good isolated yields that ranged from 92–96% (Table 6, entries 2–6). A benzaldehyde derivative with an electron

• -accepting nitro group (2l) at the para position on the ring showed a good reactivity with ethyl acetoacetate (4) and urea (5) to afford the product 7g in an excellent isolated yield (94%, Table 6, entry 7). Halogen atoms at different positions on the ring of benzaldehyde derivatives (4-F: 2m, 4-Cl; 2n, and