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

• application of these materials. Thus, Gu et al., using the example of a donor–acceptor–donor (D–A–D) polymer 64 containing a 3,4-ethylenedioxythiophene fragment, demonstrated the possibility of creating flexible IR displays based on isoindigo [112]. This polymer showed very good electrochromic characteristics

• electron donor/acceptor nature, the heterocyclic substituents, and the branching of the alkyl radical at the endocyclic nitrogen atom. Research on methods to obtain polymer isoindigo thin films and the use of additives will, in our opinion, significantly improve the efficiency of materials. In addition

Synthetic reactions driven by electron-donor–acceptor (EDA) complexes

• Zhonglie Yang,
• Yutong Liu,
• Kun Cao,
• Xiaobin Zhang,
• Hezhong Jiang and
• Jiahong Li

Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67

• , Chengdu 610100, China 10.3762/bjoc.17.67 Abstract The reversible, weak ground-state aggregate formed by dipole–dipole interactions between an electron donor and an electron acceptor is referred to as an electron-donor–acceptor (EDA) complex. Generally, upon light irradiation, the EDA complex turns into

• phenomena based on the electron-donor–acceptor (EDA) complex [1][2][3]. Significantly, a broad absorption peak unrelated to the structure, called charge-transfer band, is typically located in the visible region of the UV–vis spectrum [4], which manifests the color variability of the mixed solution of the

• depends on the association of eosin Y and oxidant 4 to a donor–acceptor EY–4 ground-system complex (high reactivity). Due to the ability of aryl groups to stabilize the formed alkenyl radical, this protocol could control regioselectivity efficiently with unsymmetrical alkynes. In addition, EPR

Biochemistry of fluoroprolines: the prospect of making fluorine a bioelement

• Vladimir Kubyshkin,
• Rebecca Davis and
• Nediljko Budisa

Beilstein J. Org. Chem. 2021, 17, 439–460, doi:10.3762/bjoc.17.40

• potential due to the hydrogen atoms at the exterior (Figure 4). This local charge plays an important role in the interaction of proline with the environment in a protein. For example, when a side chain of an aromatic residue docks onto the proline residue, they engage in a donor–acceptor interaction, while

Mesoionic tetrazolium-5-aminides: Synthesis, molecular and crystal structures, UV–vis spectra, and DFT calculations

• Vladislav A. Budevich,
• Sergei V. Voitekhovich,
• Alexander V. Zuraev,
• Vadim E. Matulis,
• Vitaly E. Matulis,
• Alexander S. Lyakhov,
• Ludmila S. Ivashkevich and
• Oleg A. Ivashkevich

Beilstein J. Org. Chem. 2021, 17, 385–395, doi:10.3762/bjoc.17.34

• delocalized into vicinal N2–N3* and C5–N5* antibonds, leading to the Lewis structures B and C, correspondingly (Scheme 3). A similar analysis of donor–acceptor interactions for the obtained structures leads to the Lewis structures D and E. Note that the structures B and D with a C5–N5 double bond have only a

• allow their independent collection. In this case, the charge goes from a donor–acceptor (S0) to a donor(+)–acceptor(−) (S1). We have studied, how the nature of the solvent can influence the S0→S1 CT. For this purpose, we calculated plots of the highest occupied molecular orbital (HOMO), the lowest

Exploring the possibility of using fluorine-involved non-conjugated electron-withdrawing groups for thermally activated delayed fluorescence emitters by TD-DFT calculation

• Dongyang Chen and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2021, 17, 210–223, doi:10.3762/bjoc.17.21

• Dongyang Chen Eli Zysman-Colman Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK 10.3762/bjoc.17.21 Abstract The trifluoromethyl group has been previously explored as a non-conjugated electron-withdrawing group in donor–acceptor

• thermally activated delayed fluorescence (TADF) emitters. In the present study, we investigate computationally the potential of other fluorine-containing acceptors, trifluoromethoxy (OCF3), trifluoromethylthio (SCF3), and pentafluorosulfanyl (SF5), within two families of donor–acceptor TADF emitters. Time

• electron exchange energy J (Equation 1), which itself is dependent on the electron density overlap between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) (Equation 2) [10][11]. Compounds possessing a donor–acceptor (D–A) structure could satisfy the requirements

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

• ]. [7]Helicenes of this group demonstrated a relatively high electron affinity and could be good candidates for electron-injection hole-blocking layers [39]. Donor–acceptor hybride [6]helicenes, consisting of carbazole and phenanthridine cores, are interesting as hole-transporting compounds [47]. At

• , we synthesized carbazole-based [6]helicenes fused with an azine ring (quinoxaline, pyrazine or pyridine ones). Scheme 2 represents the current work. We envisaged that combining the carbazole unit with the readily available azine building block would result in the formation of donor–acceptor hybrid

Naphthalonitriles featuring efficient emission in solution and in the solid state

• Sidharth Thulaseedharan Nair Sailaja,
• Iván Maisuls,
• Jutta Kösters,
• Alexander Hepp,
• Andreas Faust,
• Jens Voskuhl and
• Cristian A. Strassert

Beilstein J. Org. Chem. 2020, 16, 2960–2970, doi:10.3762/bjoc.16.246

• reports on the DSE behavior of 6,7-disubstituted naphthalene-2,3-dicarbonitrile derivatives so far. Herein we have designed and synthesized donor–acceptor (D–A) naphthalonitriles (NCNs) symmetrically γ-disubstituted with two p-functionalized phenyl moieties and investigated their photophysical properties

Selective and reversible 1,3-dipolar cycloaddition of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes with 1,3-diphenylprop-2-en-1-ones under microwave irradiation

• Alexander P. Molchanov,
• Mariia M. Efremova,
• Mariya A. Kryukova and
• Mikhail A. Kuznetsov

Beilstein J. Org. Chem. 2020, 16, 2679–2686, doi:10.3762/bjoc.16.218

• that the Lewis acid-catalyzed reaction of diaziridines with donor–acceptor cyclopropanes and aziridines affords the perhydropyridazine or triazine derivatives, respectively, in good yields [31][32][33]. The use of microwave irradiation in organic synthesis complies with the principles of green

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

• complementing the series, but did not yet describe synthetic details [7]. Xue et al. published a donor–acceptor photosensitizer for dye-sensitized solar cells, in which the N-phenylated SN4 unit serves as bridge between donor and acceptor moieties [34]. Further replacement of sulfur by nitrogen can lead to

Comparative ligand structural analytics illustrated on variably glycosylated MUC1 antigen–antibody binding

• Christopher B. Barnett,
• Tharindu Senapathi and
• Kevin J. Naidoo

Beilstein J. Org. Chem. 2020, 16, 2540–2550, doi:10.3762/bjoc.16.206

• analysis to consider how the sugar moiety could interact with the antibody (Tables S1–S7 in Supporting Information File 1). In solution, hydrogen bonds occur within the antigen between Arg5–Asp3 and Arg5–Pro8 (in order donor–acceptor) with occupancies of 31.83% and 14.32% (and 13.67%). For the Tn-antigen

Recent developments in enantioselective photocatalysis

• Callum Prentice,
• James Morrisson,
• Andrew D. Smith and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197

• ][33]. When an alkylating agent containing an aryl ring 40 (e.g., phenacyl/benzyl bromides) is used, the enamine intermediate 41 forms a coloured electron-donor acceptor (EDA) complex that can absorb visible light via an intermolecular charge-transfer state (EDA route) [14][34]. Mechanistic

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

• materials. Nowadays, organic NLO materials bearing strong donor–acceptor groups with a π-bridge have shown extensive usages in signal processing, optical storage, and telecommunication devices [4][5][6][7][8][9][10]. The flexibility to change electron-donor and acceptor groups in the molecules allows to

• having a free amino and strong donor-acceptor groups and a pyridin-2-yl moiety were synthesized by the base-catalyzed condensation of 2 with different aldehyde derivatives in ethanol, as depicted in Scheme 1. Further reactions of the dyes 3–7 with salicylaldehyde under basic conditions resulted in the

Photosensitized direct C–H fluorination and trifluoromethylation in organic synthesis

• Shahboz Yakubov and
• Joshua P. Barham

Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183

Polarity effects in 4-fluoro- and 4-(trifluoromethyl)prolines

• Vladimir Kubyshkin

Beilstein J. Org. Chem. 2020, 16, 1837–1852, doi:10.3762/bjoc.16.151

• substitution of proline with analogues can result in the conformational stabilization and polarity effects competing with each other [58]. Finally, it has been shown that fluoroprolines can alter donor–acceptor interactions of the proline ring with a tryptophan residue [59]. All these findings indicate that

Five-component, one-pot synthesis of an electroactive rotaxane comprising a bisferrocene macrocycle

• Natalie Lagesse,
• Luca Pisciottani,
• Maxime Douarre,
• Pascale Godard,
• Brice Kauffmann,
• Vicente Martí-Centelles and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2020, 16, 1564–1571, doi:10.3762/bjoc.16.128

• macrocycle–thread hydrogen bonds, with the other two macrocycle amides forming hydrogen bonds with the competitive crystallization solvent DMF. In contrast, rotaxane 1a presented four thread–macrocycle hydrogen bonds (Figure 7 and Table 1). The strength of the hydrogen bonds could be estimated by the donor

• –acceptor distances: 2.2–2.5 Å “strong, mostly covalent”, 2.5–3.2 Å “moderate, mostly electrostatic”, and 3.2–4.0 Å “weak, electrostatic” [23]. The corresponding stabilization energies were estimated to be in the ranges 40–14 kcal/mol, 15–4 kcal/mol, and < 4 kcal/mol, respectively. The macrocycle

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

Photocatalyzed syntheses of phenanthrenes and their aza-analogues. A review

• Alessandra Del Tito,
• Havall Othman Abdulla,
• Davide Ravelli,
• Stefano Protti and
• Maurizio Fagnoni

Beilstein J. Org. Chem. 2020, 16, 1476–1488, doi:10.3762/bjoc.16.123

• absorbing EDA (electron donor–acceptor) complexes with Et3N. Thus, a good variety of highly functionalized phenanthridines was prepared in excellent yields [80]. Another approach for the visible-light-promoted generation of iminyl radicals (e.g., 16.2·a,b) involved the addition of electrophilic radicals

Ferrocenyl-substituted tetrahydrothiophenes via formal [3 + 2]-cycloaddition reactions of ferrocenyl thioketones with donor–acceptor cyclopropanes

• Grzegorz Mlostoń,
• Mateusz Kowalczyk,
• André U. Augustin,
• Peter G. Jones and
• Daniel B. Werz

Beilstein J. Org. Chem. 2020, 16, 1288–1295, doi:10.3762/bjoc.16.109

• thioketones reacted with donor–acceptor cyclopropanes in dichloromethane at room temperature in the presence of catalytic amounts of Sc(OTf)3 yielding tetrahydrothiophene derivatives, products of formal [3 + 2]-cycloaddition reactions, in moderate to high yields. In all studied cases, dimethyl 2

• thioketones to form nearly equal amounts of both diastereoisomeric tetrahydrothiophenes. A low selectivity was also observed in the reaction of a 2-phthalimide-derived cyclopropane with ferrocenyl phenyl thioketone. Keywords: [3 + 2]-cycloaddition reactions; donor–acceptor cyclopropanes; ferrocenyl

• thioketones (also thionoesters) with donor–acceptor cyclopropanes 5 (D–A cyclopropanes) were realized. In contrast, thiochalcones (α,β-unsaturated aromatic thioketones) were shown to react under similar conditions with cyclopropanes 5 yielding exclusively seven-membered tetrahydrothiepines 7 as products of

Oxime radicals: generation, properties and application in organic synthesis

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Alexander S. Budnikov and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

• radical mechanism in which the iminoxyl radical is generated from the oxime anion under the action of perfluorobutyl iodide through the formation of an EDA complex (electron donor–acceptor complex, which is also called charge-transfer complex). The perfluorobutyl radical formed at this step served for the

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

• Stephanie G. E. Amos,
• Marion Garreau,
• Luca Buzzetti and
• Jerome Waser

Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103

• each of these steps, the role of A or D is assumed by a redox-active agent, either the substrate, a sacrificial electron donor/acceptor, or a reactive intermediate. This approach, usually named photoredox catalysis, has known a remarkable growth in the last decade and has given access to both neutral

• photocatalyst [118][119] or the formation of EDA complexes (electron donor–acceptor complexes) [120][121][122][123], and no method involving organophotocatalysts has been reported yet to the best of our knowledge. Nitrogen-centered radicals (NCRs) Biologically relevant compounds often contain C–N bonds

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

• OLEDs could be obtained with easy modulation of the electroluminescent properties. Recently, the first examples of versatile exciplex-forming materials which can form two different types of exciplexes, donor–acceptor/donor and acceptor/donor–acceptor, were reported for simplified non-doped white OLEDs

• an electron acceptor in donor–acceptor systems [14]. The target compounds were obtained by nucleophilic substitution reaction of the intermediate quinazoline derivative Q1 with the corresponding donor compounds. The chemical structures were characterized by 1H NMR, 13C NMR, ATRIR spectroscopy and

Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

• Nuray Altinolcek,
• Ahmet Battal,
• Mustafa Tavasli,
• William J. Peveler,
• Holly A. Yu and
• Peter J. Skabara

Beilstein J. Org. Chem. 2020, 16, 1066–1074, doi:10.3762/bjoc.16.93

• homoleptic or heteroleptic iridium(III) complexes were also reported in the construction of different OLEDs [10][11][12][13]. In OPVs, carbazole derivatives are frequently used as small molecule p-type (electron-donating) materials or electron-accepting (n-type) materials with a variety of donor–acceptor

• transport properties with positive solvatochromism. Whilst 7a showed very low emission intensity, 7b showed very high emission intensity. It is noted that the conjugation in compound 7b encompasses the N atom of the carbazole ring and the formyl functionality (viz. the donor/acceptor units of the ICT

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

• Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) UMR 6226, F-35000 Rennes, France 10.3762/bjoc.16.81 Abstract Boomerang-shaped bipyrroles containing donor–acceptor units were obtained through a tandem palladium-mediated reaction consisting of a cyclization step, involving double C–H bond

• measurements show that helicene-like boomerangs may be usable as circularly polarized luminescent materials. Keywords: donor–acceptor systems; double C–H bond activation; helicenes; pyrroles; Introduction Nanographenes and other polycyclic aromatics as well as their heterocyclic analogues are typically

• features characteristic of donor–acceptor systems (Supporting Information File 1, Figures S25–S30). For dilactams, cRnO, the HOMO orbital is primarily localized on the dilactam (bipyrrole) moiety, however, with some non-zero amplitudes on the NDA/NMI fragment, whereas the LUMO level encompasses the π

Photocatalytic deaminative benzylation and alkylation of tetrahydroisoquinolines with N-alkylpyrydinium salts

• David Schönbauer,
• Carlo Sambiagio,
• Timothy Noël and
• Michael Schnürch

Beilstein J. Org. Chem. 2020, 16, 809–817, doi:10.3762/bjoc.16.74

• , electrophilic alkyl radicals were used in several transformations, such as electrophilic cross couplings under nickel catalysis, either with boronic acids [35] or different (aryl)halides [36][37][38]. Furthermore, visible light-promoted uncatalyzed electron transfer via the formation of electron donor–acceptor

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

• candidates to study the potential electron donor–acceptor dyads [19]. Triptycene (1) consists of three benzene rings fused to a bicyclo[2.2.2]octane (BCO) skeleton, it is rigid, isolating and amenable to a wide range of chemical transformations. Due to the 120° rigid void, mono-, di-, tri-, tetra-, penta