Synthesis and properties of 6-alkynyl-5-aryluracils

• Ruben Manuel Figueira de Abreu,
• Till Brockmann,
• Alexander Villinger,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 898–911, doi:10.3762/bjoc.20.80

• observed, despite the presence of the π-donor group at the same position. However, a shoulder on the emission peak was observed, which may indicate the influence of the double bond. Finally, the quantum yields of all compounds were determined and compared. Compound 5f afforded the highest quantum yield

• with 23% and 5k the lowest with 2%. The second highest quantum yield was obtained with 5d closely followed by 5m. With regard to the previously discussed data, this could also be due to the influence of a π-donor group directly connected to the core system. This again shows the influence of the

Synthesis of new representatives of A₃B-type carboranylporphyrins based on meso-tetra(pentafluorophenyl)porphyrin transformations

• Victoria M. Alpatova,
• Evgeny G. Rys,
• Elena G. Kononova and
• Valentina A. Ol'shevskaya

Beilstein J. Org. Chem. 2024, 20, 767–776, doi:10.3762/bjoc.20.70

• [8]. Further improvement of the PDT method requires the search for new photosensitizers having higher photoactivity, tumor selectivity, and high singlet oxygen quantum yield, as well as low in vivo toxicity [7]. Therefore, some strategies have been developed to enhance the therapeutic efficiency of

Synthesis of photo- and ionochromic N-acylated 2-(aminomethylene)benzo[b]thiophene-3(2Н)-ones with a terminal phenanthroline group

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Irina V. Dubonosova,
• Olga Yu. Karlutova,
• Oleg P. Demidov,
• Alexander D. Dubonosov and
• Vladimir A. Bren

Beilstein J. Org. Chem. 2024, 20, 552–560, doi:10.3762/bjoc.20.47

• “overall quantum yield” is used in Table 1 [29]. The formation of the short-lived E-isomer was earlier observed only in vitrified solvents at 77 K or under flash photolysis conditions [14]. As such, the parameters of the thermal acyl migration under steady-state irradiation conditions were not determined

• )methyl)-N-phenylacetamide was used as an actinometer for the quantum yield calculations (φfl = 0.60 ± 0.005) [14][33]. For preparative purposes, a Sweko IP65 led emitter (SUL-S1-20W-230-4000K-WH) was used. Spectral-fluorescent experiments were performed using solutions in acetonitrile or DMSO in quartz

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• reversibly reopened by the addition of TREN as a competitive ligand. The authors reported a slight luminescence quenching in the zinc-closed state with a decrease in the quantum yield from 0.27 to 0.21. However, Hg2+ presented a special behavior with the formation of a 2:1 complex, the closing of the

• tweezers by the first equivalent generating an allosteric binding site specific to a second Hg2+ ion. While the addition of one equivalent of Hg2+ decreased the quantum yield to 0.09, the formation of a bis-coordinated [tweezers-Hg2]4+ complex resulted in a total luminescence quenching (quantum yield <10−3

Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines

• Eugeny Ivakhnenko,
• Vasily Malay,
• Pavel Knyazev,
• Nikita Merezhko,
• Nadezhda Makarova,
• Oleg Demidov,
• Gennady Borodkin,
• Andrey Starikov and
• Vladimir Minkin

Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34

• fluorescence quantum yield was determined relative to quinine bisulfate in 0.05 M H2SO4 as standard (ΦF = 0.52, excitation at 365 nm for 5a–c and 6a,b) [26] and cresyl violet perchlorate in ethanol (ΦF = 0.54, excitation at 510 nm for 10c) [27]. Mass spectrometric analysis was performed on a Bruker UHR-TOF

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

• ) were measured. The significant difference in the quantum yield values between the compounds was attributed to the increase in the population of triplet excited states because of spin–orbit coupling by bromine atoms. On the contrary with previous studies, it was found that the effect of proton and

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

• -emission (AIE)-active aggregates exhibit emissive behavior in hexane, with an emission peak at 679 nm and a shoulder at 717 nm along with a fluorescence quantum yield of 8.5%. This luminescence phenomenon can be aptly considered to be AIE, considering the pronounced constraints imposed on molecular

Visible-light-induced radical cascade cyclization: a catalyst-free synthetic approach to trifluoromethylated heterocycles

• Chuan Yang,
• Wei Shi,
• Jian Tian,
• Lin Guo,
• Yating Zhao and
• Wujiong Xia

Beilstein J. Org. Chem. 2024, 20, 118–124, doi:10.3762/bjoc.20.12

• EDA charge transfer complex because there was no obvious EDA charge transfer band in the UV–vis spectra (Figure 2). Their indole substrate was more electron-rich in structure. The quantum yield was measured to investigate whether there was a radical chain process or not. The procedure was following a

• precedent work [32] (see Supporting Information File 1), and the calculated quantum yield was 2.2, which revealed that one photon generates more than one product molecule. Based on preliminary experiments and previous reports [33][34], we propose a plausible mechanism (Scheme 4). Upon light irradiation

Optimizing reaction conditions for the light-driven hydrogen evolution in a loop photoreactor

• Pengcheng Li,
• Daniel Kowalczyk,
• Johannes Liessem,
• Mohamed M. Elnagar,
• Dariusz Mitoraj,
• Radim Beranek and
• Dirk Ziegenbalg

Beilstein J. Org. Chem. 2024, 20, 74–91, doi:10.3762/bjoc.20.9

• and reaction rate [42], which was used in this work to fit the experiment results (see Equation 4). where is the average (observed) reaction rate, k* is the kinetic rate constant, θ is the surface coverage of the photocatalyst, α is the optical density, ϕ is the quantum yield, qp is the volumetric

• transport is of major importance for the performance of the studied reaction. The used loop reactor provides excellent mass transport properties, which eventually enabled an increase of the apparent quantum yield by a factor of 10. This result is even more relevant than the demonstration of the scale-up as

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

Beilstein J. Org. Chem. 2023, 19, 1895–1911, doi:10.3762/bjoc.19.141

• characteristics, making them highly intriguing for further study and potential applications. Among the regioisomers in the series, the linear isomer 43a displayed the highest quantum yield (Φem = 0.64). Additionally, its absorption and emission max values (λmax and λmax,em) were determined to be 476 and 477 nm

• = 402 nm, λmax,em = 524 nm, Φem = 0.16) also demonstrated a substantially reduced quantum yield when compared to compound 43a. Theses regioisomers with varying geometric structures provided strong evidence that the antiaromaticity of the cyclobutadiene (CBD) ring can be tuned up with appropriate

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

• small singlet–triplet splitting and a fair photoluminescence quantum yield (PLQY). The optimized organic light-emitting diode (OLED) based on 13 wt % CPC doped in 1,3-bis(9H-carbazol-9-yl)benzene (mCP) as host exhibited maximum current efficiency, power efficiency, and external quantum efficiency (EQE

• (ΔEST) between the lowest singlet and triplet states (Figure 4d and Figure S7 in Supporting Information File 1). A ΔEST value of 0.24 eV was obtained for compound 9. The highest photoluminescence quantum yield (PLQY) of 17.1% was obtained for the dilute toluene solution of compound 8 (Table 1). The neat

Thienothiophene-based organic light-emitting diode: synthesis, photophysical properties and application

• Recep Isci and
• Turan Ozturk

Beilstein J. Org. Chem. 2023, 19, 1849–1857, doi:10.3762/bjoc.19.137

• emitter for an organic light-emitting diode through a solution process. DMB-TT-TPA (8) displayed excellent performance in both device application and photophysical properties, i.e., a maximum solution fluorescence quantum yield of 86% in THF, maximum solid-state fluorescence quantum yield of 41%, maximum

• Horiba, FL3-2IHR fluorescence spectrophotometer. Solid-state and solution-state quantum yields were measured using a Hamamatsu Quantaurus-QY Absolute PL Quantum Yield Spectrometer. Thermal gravimetric analysis (TGA) was performed on a PerkinElmer Diamond TA/TGA with a heating rate of 10 °C min−1 under

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• from Shimadzu (GC-2030) equipped with two barrier discharge ionization detectors (BID). Every test was repeated at least twice. The photon flux was evaluated with actinometry, according to a previously published procedure [42], and it was 0.025 µE s−1. Therefore, an apparent photoluminescent quantum

• yield could be estimated to be up to 2.4%, after 4 h, according to Equation 5: Where A is the initial absorption value of the photocatalytic system at the irradiation wavelength. TON and TOF were calculated according to Equation 6, Equation 7, and Equation 8: Where n is the number of moles of the

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

• twist angle between the D and A units, a strong electron deficiency of the Nz unit, and electron-donating and hole-transporting natures of carbazole, TPECNz exhibits a strong deep red emission (λem = 648 nm) with a high fluorescence quantum yield of 96%, outstanding thermal property (Tg = 236 °C), and

• . TPECNz in thin film and solid powder also displayed deep-red emission observed by PL maxima at 668 and 665 nm, respectively (Figure 2b). As listed in Table 1, the TPECNz solution shows an excellent absolute PL quantum yield (PLQY) of 96%, whereas the spin-coated thin film exhibits a red-shifted spectrum

• electron affinity of Nz unit, and electron donating and hole-transporting properties of carbazole nurtured the molecule to exhibit an intense deep-red emission with decent PL quantum yield, superior thermal property, and ambipolar charge-carrier-transporting property with a good balance of mobility of

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

• benzoguanidine donor and compare it with the benchmark carbazole-based material (4CzIPN). Extended π-conjugation in 4BGIPN material results in yellow-green luminescence at 512 nm with a fast radiative rate of 5.5 × 10−5 s−1 and a photoluminescence quantum yield of 46% in methylcyclohexane solution. Such a

• exhibits a featureless yellow CT-type luminescence with λmax = 525 nm that is 44 and 25 nm red-shifted compared to 4CzIPN (λmax = 481 and 500 nm in Zeonex and MCH, respectively) [12]. The solution photoluminescent quantum yield (PLQY) of 4BGIPN is 46% under inert atmosphere and decreases down to 18% in

• aerated MCH solution. The reduction in quantum yield on exposure to oxygen is due to quenching of the triplet excited states indicating a TADF luminescence mechanism. PLQY in Zeonex films is 39% in air, which is lower than the PLQY of 87% reported for 4CzIPN [17]. The two-component excited state lifetime

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

• ) under solvent-free conditions, through subsequent elimination of a benzamide molecule in a superbasic medium (t-BuOK/DMSO). The fluorescent properties of the synthesized compounds were studied. 4-Arylpyrazolo[3,4-b]pyridin-6-ones luminesce in the region of 409–440 nm with a quantum yield of 0.09–0.23

• ). Their diluted alcohol solutions luminesce with a quantum yield of 0.09–0.23. Pyrazolo[3,4-b]pyridinones 4a–i, 9a, and 10a are characterized by an abnormally high Stokes shift (107–152 nm, 1.07–1.49 eV, Table 2). Such luminophores, which are colorless in daylight but become colored when irradiated with

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

• ) wavelength LEDs that complicate the setup. The simpler reaction setups and lack of a heterogeneous surface (electrodes) can make the mechanistic investigation more accessible. While quantum parameters (quantum yield, quadratic relationships with light intensity, etc) have been touched upon for a

• transfer can be significantly suppressed by using photocatalysts with a more negative reduction half potential E1/2 (PC/PC•−) [73][74]. The involvement of an excited state radical anion *PC1•− was further supported by analysis of the product quantum yield (QY). The QY exceeded the theoretical limit of a

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

• possible relaxation pathway, because the orthogonal geometry of the dyads is beneficial for SOCT-ISC. Previously we have shown that SOCT-ISC occurs for the analogue of NI-PTZ-C5 [39]. In order to study the ISC efficiency of the dyads, we measured the singlet oxygen quantum yield (ΦΔ) of the dyads in

• Ltd., U.K.). Fluorescence quantum yields (ΦF) were measured by an absolute photoluminescence quantum yield spectrometer (Quantaurus-QY Plus C13534-11, Hamamatsu Ltd., Japan). Luminescence lifetimes of compounds were measured with an OB920 luminescence lifetime spectrometer (Edinburgh Instruments Ltd

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

• HPLC. Due to the large conjugated structure, NG 110 exhibited a significantly red-shifted emission in the near-infrared (NIR) region. Furthermore, the structure extension causes significant improvements both in the fluorescence quantum yield and CPL properties. The dissymmetry factors glum of (P)- and

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• albumin and LDL. Furthermore, the Zn and Pd porphyrin complexes revealed a good capability to yield singlet oxygen (quantum yield >70%) and exhibited significant photoinduced cytotoxicity. In another report, Prakash Rao et al. [65] highlighted the click protocol to accomplish the synthesis of hydrogenated

• transfer quantum yield of 0.98. These conjugates could be useful in light-harvesting applications because of their optical characteristics. In 2008, Liu et al. [67] nicely demonstrated Cu(I)-catalyzed click chemistry for the synthesis of tetrakis(PM-β-CD)-modified zinc(II) porphyrin 166a and tetra(β-CD

Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence

• Kaiyue Ye,
• Liyuan Cao,
• Davita M. E. van Raamsdonk,
• Zhijia Wang,
• Jianzhang Zhao,
• Daniel Escudero and
• Denis Jacquemin

Beilstein J. Org. Chem. 2022, 18, 1435–1453, doi:10.3762/bjoc.18.149

• can be controlled. The singlet oxygen quantum yield (ΦΔ) of NI-PTZ is moderate in n-hexane (HEX, ΦΔ = 19%). TADF was observed for the dyads, the biexponential luminescence lifetime are 16.0 ns (99.9%)/14.4 μs (0.1%) for the dyad and 7.2 ns (99.6%)/2.0 μs (0.4%) for the triad. Triplet state was

• were recorded with an FS5 spectrofluorometer (Edinburgh instruments Ltd., U.K.). Fluorescence quantum yields (ΦF) were measured by an absolute photoluminescence quantum yield spectrometer (Quantaurus-QY Plus C13534-11, Hamamatsu Ltd., Japan). Luminescence lifetimes of compounds were recorded with an

Ionic multiresonant thermally activated delayed fluorescence emitters for light emitting electrochemical cells

• Merve Karaman,
• Abhishek Kumar Gupta,
• Subeesh Madayanad Suresh,
• Tomas Matulaitis,
• Lorenzo Mardegan,
• Daniel Tordera,
• Henk J. Bolink,
• Sen Wu,
• Stuart Warriner,
• Ifor D. Samuel and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2022, 18, 1311–1321, doi:10.3762/bjoc.18.136

• for other donor decorated MR-TADF emitters [34][35][36]. The photoluminescence quantum yield, ΦPL, in MeCN for DiKTa-OBuIm is 48% which decreases in air to 34%. The emission is much weaker in DiKTa-DPA-OBuIm, reflecting both the smaller oscillator strength of the transition to S1 and the greater non

Thermally activated delayed fluorescence (TADF) emitters: sensing and boosting spin-flipping by aggregation

• Ashish Kumar Mazumdar,
• Gyana Prakash Nanda,
• Nisha Yadav,
• Upasana Deori,
• Upasha Acharyya,
• Bahadur Sk and
• Pachaiyappan Rajamalli

Beilstein J. Org. Chem. 2022, 18, 1177–1187, doi:10.3762/bjoc.18.122

• base fumes, etc. [10][11]. However, the fluorescence quantum yield of such emitters in the solid state is relatively low due to the aggregation-caused quenching (ACQ) effect [12][13][14] and limits practical applications. Hence, metal-free emitters with high photoluminescence quantum yield (PLQY) in

Synthesis, optical and electrochemical properties of (D–π)₂-type and (D–π)₂Ph-type fluorescent dyes

• Kosuke Takemura,
• Kazuki Ohira,
• Taiki Higashino,
• Keiichi Imato and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2022, 18, 1047–1054, doi:10.3762/bjoc.18.106

• and fluorescence maximum wavelengths (λmax,abs and λmax,fl) of OTT-2 appear in a longer wavelength region than those of OTK-2. The fluorescence quantum yield (Φfl) of OTT-2 is 0.41, which is higher than that (Φfl = 0.36) of OTK-2. In the solid state OTT-2 shows relatively intense fluorescence

• fluorescence quantum yield (Φfl) of OTK-2 are comparable to those of the (D–π)2A-type fluorescent dyes. More recently, we found that the (D–π)2-type fluorescent dye OTT-2 consisting of two D–π moieties is derived by oxidative homocoupling of a stannyl D–π unit. There is an obvious structural difference between

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

• a certain application, for example where charge transport is more important than photoluminescence quantum yield or vice versa. Introducing alkyl chains can provide solubility, enabling facile solution processing, such as device printing techniques [13]. Hence, there is an ongoing interest in

• , we published a series of ‘bent’ diindenodithienothiophene derivatives (2–4, Figure 2) [16]. It was observed that oxidising the central sulfur atom significantly increased the solution photoluminescence quantum yield (PLQY) from 0.004 (3) to 0.72 (4). The diketo derivative 5 of compound 2 has been