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Search for "absorption" in Full Text gives 912 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Charge carrier transport in perylene-based and pyrene-based columnar liquid crystals

  • Alessandro L. Alves,
  • Simone V. Bernardino,
  • Carlos H. Stadtlober,
  • Edivandro Girotto,
  • Giliandro Farias,
  • Rodney M. do Nascimento,
  • Sergio F. Curcio,
  • Thiago Cazati,
  • Marta E. R. Dotto,
  • Juliana Eccher,
  • Leonardo N. Furini,
  • Hugo Gallardo,
  • Harald Bock and
  • Ivan H. Bechtold

Beilstein J. Org. Chem. 2023, 19, 1755–1765, doi:10.3762/bjoc.19.128

Graphical Abstract
  • ≈3.5 Å for all mesophases. Absorption and photoluminescence (PL) of 1 and 2 are presented in Figure 3 for solution and spin-coated film. Compound 1 shows the three well-defined bands typical of perylene absorption and PL in solution. The absorption becomes broader and the PL destructured and red
  • monomeric species [34]. It agrees with the intensity inversion of the vibronic absorption bands and PL redshift in the spin-coated film compared to the solution. The intensity inversion suggests formation of H-aggregates, leading to excimer fluorescence [35]. Due to the similarity to the lifetime in
  • Optics USB4000 spectrophotometer. The PL spectra were collected with a Hitachi fluorescence spectrophotometer (Model F-7000) and the samples were excited at the wavelength of maximal absorption. For the PL as a function of the temperature, casting films were placed on a hot stage (Mettler Toledo FP-82
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Published 16 Nov 2023

Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

  • Dayanne Martins,
  • Roberta Lamosa,
  • Talis Uelisson da Silva,
  • Carolina B. P. Ligiero,
  • Sérgio de Paula Machado,
  • Daphne S. Cukierman and
  • Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

Graphical Abstract
  • stability in aqueous medium. Thus, the electronic absorption spectra of hdz-CH3 and hdz-NO2 were recorded in a 10% DMSO/buffer solution (pH 7.4) immediately after preparation and at regular time intervals. The UV–vis spectrum of hdz-CH3 between 250 and 450 nm (Figure 6A) shows two multicomponent absorptions
  • absorption profiles, being consequently assigned to the hydrazone moiety, meaning that it probably involves a transition delocalized throughout the molecule (i.e., electronic density moving from one ring to the other). No significant changes were observed in the hdz-CH3 spectra during the 48 hours of follow
  • power than the hydrazone moiety. Because of this particularity, we analyzed individually the absorption patterns of fully protonated and phenol-deprotonated hdz-NO2 at the pH values of 3.8 and 8.2, respectively. When the phenol group is protonated, the spectrum of this hydrazone is very similar to that
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Published 10 Nov 2023

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

Graphical Abstract
  • ]thiophene in different ratios to produce three copolymers, Qx1a, Qx1b and Qx1c (Figure 2). This strategy reduced aggregation and improved the performance and stability of copolymers, with Qx1c achieving a PCE of 4.81% with PTB7-Th donor in an all-PSC device. Moreover, the broadened absorption band indicated
  • molecule series, Qx16, featured a 1,4-dihydro-2,3-quinoxalinedione core and different terminal acceptor units. The modified NFAs demonstrated visible and near-infrared absorption as well as good electron mobility, suggesting their potential for experimental exploration in (OCSs) [31]. While FREAs are
  • compounds exhibited good coplanarity through intramolecular interactions, narrow bandgaps, broad absorption in the NIR region and PCEs above 10% [32]. Ayub et al. decorated the central donor–acceptor–donor unit of Qx17 and Qx18 with five new terminal end groups, resulting in the Qx19 series, and predicted
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Published 09 Nov 2023

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

Graphical Abstract
  • the D–A–D structure to further reduce the bandgap, thereby red-shifting the absorption and emission wavelengths. In addition, the strong electron affinity of Nz and the electron-donating and hole-transporting ability of carbazole would build in the good ability to transport electrons and holes
  • , thin film, and solid powder. As shown in Figure 2a, the UV–vis absorption spectrum in diluted toluene solution displays intense absorption peaks in the high energy region (<380 nm) and a much weaker absorption peak at 508 nm attributed to the π–π* transition of the conjugated aromatic backbone and
  • intramolecular charge-transfer (ICT) transition from carbazole donor to Nz acceptor, respectively. Such weak ICT absorption peak (ε = 17,000 M−1 cm−1) as compared to the π–π* absorption peak (ε = 95,300 M−1 cm−1) symbolizes a weak electronic coupling between the carbazole donor and the Nz acceptor parts because
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Published 03 Nov 2023

Benzoimidazolium-derived dimeric and hydride n-dopants for organic electron-transport materials: impact of substitution on structures, electrochemistry, and reactivity

  • Swagat K. Mohapatra,
  • Khaled Al Kurdi,
  • Samik Jhulki,
  • Georgii Bogdanov,
  • John Bacsa,
  • Maxwell Conte,
  • Tatiana V. Timofeeva,
  • Seth R. Marder and
  • Stephen Barlow

Beilstein J. Org. Chem. 2023, 19, 1651–1663, doi:10.3762/bjoc.19.121

Graphical Abstract
  • not react significantly with VII in solution at room temperature, while the reactions of 12 derivatives and VI are very rapid) [9][14][50][61]. Figure 8a compares the evolution of the absorbance at 1030 nm, corresponding to a VI•– absorption maximum, when doping excess VI with 1H derivatives in
  • strongly bound dimers. Figure 8b compares the evolution of one of the distinctive VII •– absorptions when doping VII with excess 12 derivatives in chlorobenzene at 293 K in the absence of light, air, and water. In the case of the Y = 4-dimethylaminophenyl dimers 1b2 and 1g2, the VII•– absorption grows in
  • the rise in VII•– absorption is neither zero-order nor first-order in VII, consistent with both mechanisms contributing, as previously demonstrated by more extensive investigations in the case of 1c2, 1d2, and (RhCp*Cp)2 [14][61]. Thus, the Y = alkyl derivative (1h2, “ET-first” only) appears to be
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Published 01 Nov 2023

Tying a knot between crown ethers and porphyrins

  • Maksym Matviyishyn and
  • Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

Graphical Abstract
  • alkali metals. Due to the presence of crown ether moieties, the receptors exhibited selective binding of K+, NH4+, and Ba2+. The pronounced changes in the absorption spectra of free-base ligands 1 and TriCP with adding K+, NH4+, and Ba2+ cations were observed, whereas Na+, Mg2+, and Ca2+ did not produce
  • appreciable effects. Furthermore, zinc(II) porphyrins 1-Zn and TriCP-Zn bound potassium cations forming dimeric assemblies 2, as demonstrated by the absorption and 1H NMR spectra. Although DCP-Zn and MCP-Zn were also capable of forming dimers, the highest stability and the largest level of attraction between
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Published 27 Oct 2023

Sulfur-containing spiroketals from Breynia disticha and evaluations of their anti-inflammatory effect

  • Ken-ichi Nakashima,
  • Naohito Abe,
  • Masayoshi Oyama,
  • Hiroko Murata and
  • Makoto Inoue

Beilstein J. Org. Chem. 2023, 19, 1604–1614, doi:10.3762/bjoc.19.117

Graphical Abstract
  • formula of C45H64O28SNa (calcd 1107.3197). The IR spectrum showed absorption peaks corresponding to hydroxy groups (νmax = 3414 cm−1) and carbonyl groups (νmax = 1782 and 1695 cm−1). The 1H NMR signals (Table 1) were characteristic of a breynogenin moiety, namely, a methyl group [δH 0.92 (d, J = 6.9 Hz
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Published 19 Oct 2023

Synthesis of 5-arylidenerhodanines in L-proline-based deep eutectic solvent

  • Stéphanie Hesse

Beilstein J. Org. Chem. 2023, 19, 1537–1544, doi:10.3762/bjoc.19.110

Graphical Abstract
  • give a purple solution and present a strong absorption maximum at 517 nm. In the presence of an antioxidant compound DPPH is reduced forming DPPH-H and the color of the solution changes to yellow. The overall antioxidant capacity of compounds was measured after 30 minutes of incubation. We used the
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Published 04 Oct 2023

Consecutive four-component synthesis of trisubstituted 3-iodoindoles by an alkynylation–cyclization–iodination–alkylation sequence

  • Nadia Ledermann,
  • Alae-Eddine Moubsit and
  • Thomas J. J. Müller

Beilstein J. Org. Chem. 2023, 19, 1379–1385, doi:10.3762/bjoc.19.99

Graphical Abstract
  • absorption maximum of indole derivative 8b appears at 309 nm with an absorption coefficient ε = 10700 M−1 cm−1 and the emission maximum is found at 423 nm with a Stokes shift of 8700 cm−1 (Figure 1A). Moreover, compound 8b emits intensively blue in both the solid state and solution (Figure 1B). Conclusion In
  • , 6.29; N, 4.52. A: Absorption and emission spectra of 1-methyl-2-phenyl-3-(p-tolyl)-1H-indole (8b), recorded in dichloromethane, T = 298 K, λexc = 290 nm. B: Emission of compound 8b in the solid state (right) and in solution (left) (UV lamp, λexc = 365 nm. Consecutive alkynylation–cyclization–alkylation
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Published 14 Sep 2023

Synthesis of ether lipids: natural compounds and analogues

  • Marco Antônio G. B. Gomes,
  • Alicia Bauduin,
  • Chloé Le Roux,
  • Romain Fouinneteau,
  • Wilfried Berthe,
  • Mathieu Berchel,
  • Hélène Couthon and
  • Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

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Published 08 Sep 2023

Organic thermally activated delayed fluorescence material with strained benzoguanidine donor

  • Alexander C. Brannan,
  • Elvie F. P. Beaumont,
  • Nguyen Le Phuoc,
  • George F. S. Whitehead,
  • Mikko Linnolahti and
  • Alexander S. Romanov

Beilstein J. Org. Chem. 2023, 19, 1289–1298, doi:10.3762/bjoc.19.95

Graphical Abstract
  • for 4BGIPN are shown in Figure 4 and Figure 5 while data in various media is collected in Table 2 and Table 3, respectively. UV–vis absorption spectra of 4BGIPN show a strong π–π* intraligand transition (IL, benzoguanidine) at 290 nm with ε = 42000 M−1cm−1. Unlike 4CzIPN, we do not observe any
  • vibronically resolved carbazole absorption peaks which are commonly present at 325 nm [15]. Similar to 4CzIPN [14][15], the UV–vis profile has two broad regions: localized charge transfer (loCT) over 320–380 nm region with ε up to 14000 M−1 cm−1 and a delocalized charge transfer (deCT) broad shoulder over the
  • , equipped with an AFC-11 4-circle kappa goniometer, VariMAXTM microfocus optics, a Hypix-6000HE detector and an Oxford Cryosystems 800 plus nitrogen flow gas system, at a temperature of 100 K. Data were collected and reduced using CrysAlisPro v42 [21][22]. Absorption correction was performed using empirical
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Published 07 Sep 2023

Unravelling a trichloroacetic acid-catalyzed cascade access to benzo[f]chromeno[2,3-h]quinoxalinoporphyrins

  • Chandra Sekhar Tekuri,
  • Pargat Singh and
  • Mahendra Nath

Beilstein J. Org. Chem. 2023, 19, 1216–1224, doi:10.3762/bjoc.19.89

Graphical Abstract
  • ) porphyrins were transformed to the corresponding free base and zinc(II) benzo[f]chromeno[2,3-h]quinoxalinoporphyrins under standard demetallation and zinc insertion conditions. The absorption and emission properties of the obtained porphyrins were investigated by using UV–visible and fluorescence
  • spectroscopy. The preliminary photophysical results revealed a significant red-shift in their absorption and emission spectra as compared to the meso-tetrakis(4-methylphenyl)porphyrins due to the extended π-conjugation. Keywords: bathochromic shift; benzo[f]chromeno[2,3-h]quinoxalinoporphyrins; catalysis
  • other materials applications [4][5][6][7]. Among the previously synthesized synthetically modified porphyrinoids, β,β’-fused meso-tetraphenylporphyrins have gained a considerable importance because of their red-shifted absorption and emission due to the extended π-conjugation. In particular, β,β’-fused
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Published 11 Aug 2023
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  • considered: solubility in the chosen solvent, absorption spectrum, oxidation potential, and the reversibility of the sacrificial donor oxidation. As the sacrificial donor is a reactant in the photoreduction reaction of carbon dioxide, it needs to be highly soluble in the solvent used. It also needs to have a
  • low absorption in the visible region to prevent side reactions and allow the photosensitizer to absorb as much light as possible. The oxidation potential of the sacrificial electron donor must be less positive than the reduction potential of the excited or oxidized photosensitizer for quenching or
  • catalyst [56]. This allowed the electron to be promoted by 2 photon absorption events, making it a Z-scheme. It can be argued that the linking ruthenium chromophore was acting as a redox mediator. Rather than using water as the sacrificial donor in this work, they used methanol which can be produced by
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Published 08 Aug 2023

Cyanothioacetamides as a synthetic platform for the synthesis of aminopyrazole derivatives

  • Valeriy O. Filimonov,
  • Alexandra I. Topchiy,
  • Vladimir G. Ilkin,
  • Tetyana V. Beryozkina and
  • Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2023, 19, 1191–1197, doi:10.3762/bjoc.19.87

Graphical Abstract
  • accomplished on the automated X-ray diffractometer «Xcalibur 3» with CCD detector following standard procedures (Mo Kα-irradiation, graphite monochromator, ω-scans with 1o step at T = 295(2) K). Empirical absorption correction was applied. The structure was solved using the intrinsic phases in ShelXT program
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Published 08 Aug 2023

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

  • Carlee A. Montgomery and
  • Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

Graphical Abstract
  • potential to alter the physical properties (e.g., stability, solubility, UV–vis absorption) of an ylide, as well as bias a Lewis base’s σ-hole selectivity through σ-hole blocking, which represent emerging avenues for tuning an ylide’s reactivity and improving its reaction outcomes. Review 1 Halogen bonding
  • to changes in an ylide’s UV–vis absorption profile, or to its overall basicity or nucleophilicity, both of which could lead new and unexpected reactivity. The first example that specifically invoked electron donor–acceptor complexes of iodonium ylides was reported in 2018 by Wang and co-workers [122
  • a near identical mechanism to that of Wang (Figure 8). Strong evidence for formation of an initial EDA complex was found when measuring the UV–vis absorption spectra of 39, alone and in the presence of 32. The latter showed a significant absorption red shift, which implied a structural change in 39
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Published 07 Aug 2023

New one-pot synthesis of 4-arylpyrazolo[3,4-b]pyridin-6-ones based on 5-aminopyrazoles and azlactones

  • Vladislav Yu. Shuvalov,
  • Ekaterina Yu. Vlasova,
  • Tatyana Yu. Zheleznova and
  • Alexander S. Fisyuk

Beilstein J. Org. Chem. 2023, 19, 1155–1160, doi:10.3762/bjoc.19.83

Graphical Abstract
  • . We recorded absorption and fluorescence spectra of ethanolic solutions of compounds 4a–i, 9a, and 10a. The emission and absorption spectra of all the compounds differ slightly from each other. Their spectral parameters are presented in Table 2. In the UV spectra of ethanolic solutions of compounds 4a
  • -aminopyrazoles 1, 5, 6 and azlactones 2a–i, followed by heating the resulting intermediate in DMSO in the presence of t-BuOK. Photophysical properties of the obtained compounds were studied. Biologically active 4-arylpyrazolo[3,4-b]pyridin-6-ones. Normalized absorption and fluorescence spectra of solutions of
  • compounds 4a–i, 9a, and 10a in EtOH. Methods for the synthesis of 4-arylpyrazolo[3,4-b]pyridin-6-ones. One-pot synthesis of 4-arylpyrazolo[3,4-b]pyridin-6-ones 4a–i, 9a, and 10a. Optimization of reaction conditionsa. Data of absorption and fluorescence spectra of compounds 4a–i, 9a, and 10a.a Supporting
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Published 02 Aug 2023

Photoredox catalysis harvesting multiple photon or electrochemical energies

  • Mattia Lepori,
  • Simon Schmid and
  • Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

Graphical Abstract
  • mentioned, the energy accessible for a PRC reaction relying on a single visible photon is limited and does not suffice for many desirable target organic substrates. Direct cumulative absorption of visible light photons by a given molecule is extremely challenging, since the short lifetimes of excited states
  • ’ conPET, this Review will also cover deviating variants such as neutral (acridine) radical conPET as well as polysulfide or ‘tandem’ photoredox catalysis that similarly rely on the absorption of two photons to access activated catalyst states that engage redox-inert substrates. Other two-photon processes
  • photoredox catalysis reaction setups, although it should be noted that since there are two photoactive species with often different absorption bands or different extinction coefficients at any given wavelength, it is necessary to use i) polychromatic wavelength which is less well-defined or ii) dual(/multi
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Published 28 Jul 2023

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

Graphical Abstract
  • capability of the PTZ and NI moieties, respectively, by oxidation of the PTZ unit, or by using different aryl substituents attached to the NI unit. This tuning effect was manifested in the UV–vis absorption and fluorescence emission spectra, e.g., in the change of the charge transfer absorption bands. TADF
  • transient absorption spectra showed that the charge separation takes ca. 0.6 ps, and admixtures of locally excited (3LE) state and charge separated (1CS/3CS) states formed (in n-hexane). The subsequent charge recombination from the 1CS state takes ca. 7.92 ns. Upon oxidation of the PTZ unit, the beginning
  • of charge separation is at 178 fs and formation of 3LE state takes 4.53 ns. Nanosecond transient absorption (ns-TA) spectra showed that both 3CS and 3LE states were observed for the dyads showing TADF, whereas only 3LE or 3CS states were observed for the systems lacking TADF. This is a rare but
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Published 19 Jul 2023

CO2 complexation with cyclodextrins

  • Cecilie Høgfeldt Jessen,
  • Jesper Bendix,
  • Theis Brock Nannestad,
  • Heloisa Bordallo,
  • Martin Jæger Pedersen,
  • Christian Marcus Pedersen and
  • Mikael Bols

Beilstein J. Org. Chem. 2023, 19, 1021–1027, doi:10.3762/bjoc.19.78

Graphical Abstract
  • characteristic water absorption at 3200–3600 cm−1 and the C=O band of CO2 at 2350 cm−1 during the both weigth losses but mainly CO2 at the first lump and predominantly water at the second loss. This also suggest a comparatively weak binding of the CO2. We determined the binding constant for CO2 to cyclodextrins
  • equilibration for 2 hours, a change in the vis spectrum (Figure 4). The change was consistent with the displacement of 7 from the cavity by CO2 and change in the amount of azodye was used to calculate the amount of CO2 bound to the cyclodextrin. From the change in absorption at 370 nm as compared to the
  • ). Final cell constants were obtained from least squares fits of several thousand strong reflections. Intensity data were corrected for absorption using intensities of redundant reflections with the program SADABS (Sheldrick, G. version 2008/2; University of Göttingen: Germany, 2003). The structures were
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Published 17 Jul 2023

Cyclodextrins as building blocks for new materials

  • Miriana Kfoury and
  • Sophie Fourmentin

Beilstein J. Org. Chem. 2023, 19, 889–891, doi:10.3762/bjoc.19.66

Graphical Abstract
  • biocompatible. Thus, these supra-architectures have a multitude of uses in food, biomedicine, regenerative medicine, cosmetics, molecular electronics, polymer chemistry, gold recovery, gas absorption, depollution, biochemical material sciences, nanotechnology, self-healing materials, 3D printing, and so on [19
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Published 19 Jun 2023

Light-responsive rotaxane-based materials: inducing motion in the solid state

  • Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

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  • different flexibility. The crown ether derivative acts as a chassis in order to fix the thread. A ferrocenyl group attached at one of the ends of the linear component serves as a photosensitizer allowing the absorption of visible light. The different substitution induced different types of deformations
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Published 14 Jun 2023

A fluorescent probe for detection of Hg2+ ions constructed by tetramethyl cucurbit[6]uril and 1,2-bis(4-pyridyl)ethene

  • Xiaoqian Chen,
  • Naqin Yang,
  • Yue Ma,
  • Xinan Yang and
  • Peihua Ma

Beilstein J. Org. Chem. 2023, 19, 864–872, doi:10.3762/bjoc.19.63

Graphical Abstract
  • detection methods include atomic absorption spectroscopy, mass spectrometry, emission spectroscopy and electrochemical methods [4][5][6][7]. These detection methods are expensive and time-consuming, and the detection of samples becomes extremely difficult. Therefore, it is of great significance to construct
  • absorption [39]. Because the N atom on the pyridine ring of the G molecule has lone-pair electrons, it can form coordination compounds with metal ions. At present, the host–guest fluorescent probes designed by G and Q[n]s have been rarely reported. Therefore, we constructed the host–guest fluorescent probes
  • detection of heavy metal ions. Results and Discussion The interactions of G with TMeQ[6] UV–vis spectroscopy analysis The binding interaction between G and TMeQ[6] in aqueous solution was studied using UV–vis absorption spectroscopy. Figure 2a shows that the absorbance of G decreases with the addition of
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Published 13 Jun 2023

Synthesis of substituted 8H-benzo[h]pyrano[2,3-f]quinazolin-8-ones via photochemical 6π-electrocyclization of pyrimidines containing an allomaltol fragment

  • Constantine V. Milyutin,
  • Andrey N. Komogortsev,
  • Boris V. Lichitsky,
  • Mikhail E. Minyaev and
  • Valeriya G. Melekhina

Beilstein J. Org. Chem. 2023, 19, 778–788, doi:10.3762/bjoc.19.58

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  • proposed. Keywords: allomaltol; dihydrobenzo[h]pyrano[2,3-f]quinazolines; 6π-electrocyclization; photocyclization; pyrimidines; Introduction Photochemical processes involve absorption of UV light leading to the generation of molecules in the excited state and subsequent chemical transformations [1][2
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Published 07 Jun 2023

Construction of hexabenzocoronene-based chiral nanographenes

  • Ranran Li,
  • Di Wang,
  • Shengtao Li and
  • Peng An

Beilstein J. Org. Chem. 2023, 19, 736–751, doi:10.3762/bjoc.19.54

Graphical Abstract
  • –Alder reaction, yielded the polyphenylene precursor 124 in an overall 12% yield. At last, a Scholl oxidation, mediated by DDQ and TfOH, gave the target NG 125 in a 6% yield. Due to the extremely large conjugated structure, compound 125 shows an extraordinary panchromatic light absorption capability (ε
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Published 30 May 2023

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

Graphical Abstract
  • the extent of π-conjugation and the efficiency of particular donor–acceptor conjugation path in these new compounds. X-ray structures and absorption spectra of doubly protonated tetrafluoroborate salts of the oligomers are also discussed. Keywords: 1,8-bis(dimethylamino)naphthalene; cross-conjugated
  • 6 is identical to the “blue” one in oligomers 5 (Figure 7). Thus, the UV–vis spectra of compounds 1 and 6 were used for comparison (Table 3, Figure 8). The long-wave absorption maximum of the yellow-colored butadiyne 1 is observed at 429 nm (lg ε = 4.33) [15]. Compounds 5a‒с (R = H, OMe, CF3) are
  • yellow, 5d (R = CN) is orange, and 5e (R = NO2) is a crimson crystalline substance. As can be seen from Table 3, compound 5b with electron-releasing methoxy groups shows the smallest λmax value, while the absorption maximum of the nitro derivative 5e is the most red-shifted in the series. There is a
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Published 15 May 2023
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