Biobased carbon dots as photoreductants – an investigation by using triarylsulfonium salts

• Valentina Benazzi,
• Arianna Bini,
• Ilaria Bertuol,
• Mariangela Novello,
• Federica Baldi,
• Matteo Hoch,
• Alvise Perosa and
• Stefano Protti

Beilstein J. Org. Chem. 2025, 21, 1024–1030, doi:10.3762/bjoc.21.84

• tail extending to the visible region. The emission properties of the synthesized CDs were also investigated and the results are summarized in Table 2. The fluorescence quantum yield strongly depends on the nature of the starting substrates, as is apparent by comparison of the value obtained for

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

• photoluminescence quantum yield (ϕ) combined with improved photostability. The spin-allowed transition from the excited doublet state to the ground state [7][8][9][10][11][12][13], combined with the absence of competing triplet states – which is a major pathway of efficiency loss in closed-shell emitters – promises

• mechanisms and reasons behind the fluorescence color and the fluorescence quantum yield and derive structure–optical property relationships. We will provide the reader with an overview of the perspectives and challenges of open-shell light-emitting radicals and discuss what to do to solve the remaining

Study of tribenzo[b,d,f]azepine as donor in D–A photocatalysts

• Katy Medrano-Uribe,
• Jorge Humbrías-Martín and
• Luca Dell’Amico

Beilstein J. Org. Chem. 2025, 21, 935–944, doi:10.3762/bjoc.21.76

• ), and 5c (3.7 eV). At the same time, 5a and 5b showed bigger values (3.9 eV and 4.0 eV, respectively) (Figure 2). The strength of common donors plays a crucial role in influencing quantum yield (QY) measurements. As shown in Table 1, we observe a notable decrease in QY across the PCs 5e, 5d, and 5c

Substituent effects in N-acetylated phenylazopyrazole photoswitches

• Radek Tovtik,
• Dennis Marzin,
• Pia Weigel,
• Stefano Crespi and
• Nadja A. Simeth

Beilstein J. Org. Chem. 2025, 21, 830–838, doi:10.3762/bjoc.21.66

• bathochromic shift of the n→π* absorption band further moving their UV–vis absorption spectrum towards the therapeutic window [35]. Moreover, a similar modification in stilbene-based photoswitches and molecular motors showed an increase in performance and photoisomerization quantum yield [36][37]. Consequently

• the n→π* transition is selectively addressed, with similar or markedly reduced quantum yields. A deviation from Kasha's rule with the opposite outcome (viz. the quantum yield of isomerization proceeding from the excitation of the π→π* state is lower than the one from the n→π*) is reported in various

• in CH3CN. UV–vis absorption maxima of Z-PAP derivatives in CH3CN (obtained through 365 nm irradiation to the corresponding PSS365). PSS distribution of various NAc-PAP derivatives.a Quantum yield values for the E→Z and Z→E photoisomerization of PAP derivatives with the corresponding 365 nm and 445 nm

Photochemically assisted synthesis of phenacenes fluorinated at the terminal benzene rings and their electronic spectra

• Yuuki Ishii,
• Minoru Yamaji,
• Fumito Tani,
• Kenta Goto,
• Yoshihiro Kubozono and
• Hideki Okamoto

Beilstein J. Org. Chem. 2025, 21, 670–679, doi:10.3762/bjoc.21.53

• processes contributing to the low fluorescence quantum yield of the F8-phenacenes (cf. Table 1). Because fluorescence behavior in the solid state reflects molecular alignment and intermolecular interactions in the crystals, solid-state fluorescence of the F8-phenacenes was investigated. We observed

Deep-blue emitting 9,10-bis(perfluorobenzyl)anthracene

• Long K. San,
• Sebastian Balser,
• Brian J. Reeves,
• Tyler T. Clikeman,
• Yu-Sheng Chen,
• Steven H. Strauss and
• Olga V. Boltalina

Beilstein J. Org. Chem. 2025, 21, 515–525, doi:10.3762/bjoc.21.39

• photochemical reaction. Its structure was elucidated by NMR spectroscopy and single crystal X-ray diffractometry. The latter revealed no π–π interaction between neighboring ANTH cores. A combination of high photoluminescence quantum yield (PLQY) of 0.85 for 9,10-ANTH(BnF)2, its significantly improved

• -emitting device. The photophysical data of ANTH and 9,10-disubstituted anthracene derivatives are summarized in Table 1. The measured photoluminescence quantum yield, PLQY (Φf) of ANTH in cyclohexane is in agreement with the literature values of 0.28–0.36 [32][33][34][35]. An increase in Φf was previously

Unprecedented visible light-initiated topochemical [2 + 2] cycloaddition in a functionalized bimane dye

• Metodej Dvoracek,
• Brendan Twamley,
• Mathias O. Senge and
• Mikhail A. Filatov

Beilstein J. Org. Chem. 2025, 21, 500–509, doi:10.3762/bjoc.21.37

• suggest potential triplet-state formation, which is involved in the proposed mechanism for the cycloaddition reaction. Although Me4B could theoretically form triplet states, given its fluorescence quantum yield of 51.7–67.3%, its crystallographic structure is not conducive to this reaction, regardless of

• fluorescence spectra are presented in Supporting Information File 1 (Figures S12–S14). For the fluorescence quantum yield measurements, solutions of each bimane were prepared, and the concentration was adjusted so that the absorbance at the right shoulder of the band at 360 nm falls within the range of 0.03

• reference (Φfl = 33%) [19]. Quantum yields were calculated using the following formula (Equation 1): where Φs is the fluorescence quantum yield of the analyte and Φref is the fluorescence quantum yield of the reference, Abs is the absorbance at the excitation wavelength, Area is the area under the

Synthesis of N-acetyl diazocine derivatives via cross-coupling reaction

• Thomas Brandt,
• Pascal Lentes,
• Jeremy Rudtke,
• Michael Hösgen,
• Christian Näther and
• Rainer Herges

Beilstein J. Org. Chem. 2025, 21, 490–499, doi:10.3762/bjoc.21.36

• Abstract Diazocines are photoswitches derived from azobenzenes by bridging the two phenyl rings in ortho position with a CH2CH2 group forming an eight membered (diazocine) ring. Diazocine is superior to most azobenzenes in almost all photophysical properties (switching efficiency, quantum yield

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• transition-metal-based photosensitizers acting by triplet energy transfer for which high singlet oxygen quantum yields are crucial, the silicon phthalocyanins in this study have exhibited relatively low singlet oxygen quantum yield values (around 0.27 for the silicon-based photocatalysts used in this work

Synthesis and characterizations of highly luminescent 5-isopropoxybenzo[rst]pentaphene

• Islam S. Marae,
• Jingyun Tan,
• Rengo Yoshioka,
• Zakaria Ziadi,
• Eugene Khaskin,
• Serhii Vasylevskyi,
• Ryota Kabe,
• Xiushang Xu and
• Akimitsu Narita

Beilstein J. Org. Chem. 2025, 21, 270–276, doi:10.3762/bjoc.21.19

• properties were investigated by UV–vis absorption and fluorescence spectroscopy in compassion to pristine BPP and its oxidation product, benzo[rst]pentaphene-5,8-dione (BPP-dione). BPP-OiPr exhibited a significantly enhanced photoluminescence quantum yield (PLQY), reaching 73% in comparison to pristine BPP

• ], perylene [18][19], and coronene [20]. Besides their limited accessibility in the past, the lack of attention to BPP can presumably be ascribed to its low photoluminescence quantum yield (PLQY). We recently reported a PLQY of 13% for pristine BPP and revealed a symmetry-forbidden nature of its first excited

Streamlined modular synthesis of saframycin substructure via copper-catalyzed three-component assembly and gold-promoted 6-endo cyclization

• Asahi Kanno,
• Ryo Tanifuji,
• Satoshi Yoshida,
• Sota Sato,
• Saori Maki-Yonekura,
• Kiyofumi Takaba,
• Jungmin Kang,
• Kensuke Tono,
• Koji Yonekura and
• Hiroki Oguri

Beilstein J. Org. Chem. 2025, 21, 226–233, doi:10.3762/bjoc.21.14

• displayed a relatively broad peak with a maximum around 490 nm (blue solid line). The excitation spectra of 18 (blue dashed line), corresponding to an emission at 490 nm, was also recorded (Figure S3, Supporting Information File 1 for details). Despite the modest emission quantum yield (Φfl = 0.07, excited

Synthesis, structure and π-expansion of tris(4,5-dehydro-2,3:6,7-dibenzotropone)

• Yongming Xiong,
• Xue Lin Ma,
• Shilong Su and
• Qian Miao

Beilstein J. Org. Chem. 2025, 21, 1–7, doi:10.3762/bjoc.21.1

• orange solution in common organic solvents, and its solution in cyclohexane exhibits very weak orange photoluminescence with a quantum yield as low as 3.9 × 10−4 upon excitation at 400 nm. Such a low photoluminescence quantum yield may be attributed to the conformational motions of the helicene moieties

Efficient synthesis of fluorinated triphenylenes with enhanced arene–perfluoroarene interactions in columnar mesophases

• Yang Chen,
• Jiao He,
• Hang Lin,
• Hai-Feng Wang,
• Ping Hu,
• Bi-Qin Wang,
• Ke-Qing Zhao and
• Bertrand Donnio

Beilstein J. Org. Chem. 2024, 20, 3263–3273, doi:10.3762/bjoc.20.270

• been studied in various solutions and thin film: G66 emitted green light in solution with an absolute photoluminescent quantum yield of ca. 33%. Results and Discussion Synthesis and characterization We have recently generalized a very efficient “palladium-free” synthesis for the preparation of a

Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts

• Mandeep K. Chahal

Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257

• splitting, high quantum yield for intersystem crossing, and long triplet state lifetime, act as robust electron mediators. This section highlights the use of metal-free porphyrins in organic photoredox catalysis. So far, mainly planar metal-free porphyrins have been explored as photoredox catalysts, paving

Extension of the π-system of monoaryl-substituted norbornadienes with acetylene bridges: influence on the photochemical conversion and storage of light energy

• Robin Schulte,
• Dustin Schade,
• Thomas Paululat,
• Till J. B. Zähringer,
• Christoph Kerzig and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 3061–3068, doi:10.3762/bjoc.20.254

• , such as absorption in the range of the solar spectrum, a high quantum yield of the photoreaction, long half-lives of the photoproducts, and a high energy storage density [7][8][12][13][14]. In this context, several different MOST systems have been explored, including, for example, anthracenes [15

• sunlight. Furthermore, the photoisomerization quantum yield is very low and therefore not suitable for an application [7][8][14]. One promising way to overcome these disadvantages is the introduction of a donor–acceptor system at the norbornadiene double bonds, which has resulted in the development of new

• and the analogues 1c and 1e without an alkyne linker [29][30][34]. As the only exception, the m-substituted derivative 1k has a higher quantum yield than its analog 1b, which is, however, still lower than the one of the cyano-substituted norbornadiene 1c [30][34]. In addition, substitution at the 2

Tunable full-color dual-state (solution and solid) emission of push–pull molecules containing the 1-pyrindane moiety

• Anastasia I. Ershova,
• Sergey V. Fedoseev,
• Konstantin V. Lipin,
• Mikhail Yu. Ievlev,
• Oleg E. Nasakin and
• Oleg V. Ershov

Beilstein J. Org. Chem. 2024, 20, 3016–3025, doi:10.3762/bjoc.20.251

• unchanged. This represents a rare approach for the design of such fluorophores. Arylidene derivatives of pyrindane were found to be efficient fluorescent dyes showing a moderate to high emission quantum yield. The push–pull molecules were also characterized by a dual-state emission (in solution and in the

• , indicating that the more polar singlet excited state (S1) was much better stabilized by polar solvents than the ground state (S0). The highest fluorescence quantum yield of about 87% was observed in toluene. Then, the solvatochromic properties of stilbazole 1i, bearing a stronger electron-donating

• 1 in toluene were characterized by a high fluorescence quantum yield, reaching 87.5% for the para-methoxy-substituted derivative 1c. Emission maxima in DMSO were found to be in the range of 506–721 nm (Figure 6, right), associated with a fluorescence color from green to red (Figure 7, bottom). The

Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• involving variations in light exposure and quantum yield established the need for continuous irradiation and eliminated the possibility of a radical chain mechanism for the reaction. Recently in 2023, Yadav and colleagues demonstrated that diaryliodonium salts are effective for arylating and cyclizing

Synthesis of pyrrole-fused dibenzoxazepine/dibenzothiazepine/triazolobenzodiazepine derivatives via isocyanide-based multicomponent reactions

• Marzieh Norouzi,
• Mohammad Taghi Nazeri,
• Ahmad Shaabani and
• Behrouz Notash

Beilstein J. Org. Chem. 2024, 20, 2870–2882, doi:10.3762/bjoc.20.241

• numerous reports, quantum yield is one of the most important photophysical parameters for describing luminescent molecules and materials since high quantum efficiency is important for a wide range of applications, including displays, lasers, bio-imaging, solar cells, and accurate measurement of the quantum

• yield is therefore important [52][53][54]. Therefore, the quantum yield was determined using the standard of quinine sulfate for all the products (4a–l and 6a–h). Products 4a and 6c, which had the highest intensity of absorption and emission from derivatives of benzoxazepines and triazolobenzodiazepines

• , respectively, their quantum yield was calculated and 4a was obtained with 48.35% and 6c with 1.04% (Figure 5A and 5B) [55]. According to the results obtained from the quantum yield, we can claim that these synthesized derivatives pyrrole-fused dibenzoxazepine/dibenzothiazepine/triazolobenzodiazepine

Investigation of a bimetallic terbium(III)/copper(II) chemosensor for the detection of aqueous hydrogen sulfide

• Parvathy Mini,
• Michael R. Grace,
• Genevieve H. Dennison and
• Kellie L. Tuck

Beilstein J. Org. Chem. 2024, 20, 2818–2826, doi:10.3762/bjoc.20.237

• exhibited high luminescence (with a quantum yield of 68%) and displayed the characteristic trivalent terbium emission bands with emission peaks at 491 nm, 545 nm, 583 nm, and 621 nm, corresponding to transitions from the 5D4 excited state to the 7F6, 7F5, 7F4, and 7F3 ground states, respectively (Figure 2

• glutathione. The change in luminescence emission spectra (λex = 250 nm) of the solutions was also investigated after the subsequent addition of 1.0 molar equivalent of 1 mM Na2S(aq). Quantum yields. The quantum yield (φ) was determined using a quinine sulfate standard (φ = 0.55) for Tb·1, in water at pH 7.4

Synthesis of benzo[f]quinazoline-1,3(2H,4H)-diones

• Ruben Manuel Figueira de Abreu,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2708–2719, doi:10.3762/bjoc.20.228

• , the presence of N,N-dimethylamino groups leads to strongly enhanced quantum yields up to 71%. The highest quantum yield is observed for 5d (71%), followed by 5f with 51%. However, the presence of a pair of donor and acceptor groups appears to be disadvantageous in terms of quantum yield and the

5th International Symposium on Synthesis and Catalysis (ISySyCat2023)

• Anthony J. Burke and
• Elisabete P. Carreiro

Beilstein J. Org. Chem. 2024, 20, 2704–2707, doi:10.3762/bjoc.20.227

• fluorescence quantum yield, which is an important property for their potential application in the field of optoelectronics (particularly for energy and biological chemistry applications). In this thematic issue, Nieto et al. contributed a timely Review article on the chemical space of 2-phenethylamines

Photoluminescence color-tuning with polymer-dispersed fluorescent films containing two fluorinated diphenylacetylene-type fluorophores

• Kazuki Kobayashi,
• Shigeyuki Yamada,
• Motohiro Yasui and
• Tsutomu Konno

Beilstein J. Org. Chem. 2024, 20, 2682–2690, doi:10.3762/bjoc.20.225

• 10 s. For photophysical measurements, thin and smooth films were prepared by spin-coating followed by solvent evaporation. Photophysical properties The PL spectra and quantum yields were measured using a Quantaurus-QY C11347-01 absolute PL quantum yield spectrometer (Hamamatsu Photonics, Japan). The

Metal-free double azide addition to strained alkynes of an octadehydrodibenzo[12]annulene derivative with electron-withdrawing substituents

• Naoki Takeda,
• Shuichi Akasaka,
• Susumu Kawauchi and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2024, 20, 2234–2241, doi:10.3762/bjoc.20.191

• addition. Thus, compound 6a shows an ultraviolet absorption peak at 249 nm (λmax) and no absorption in the visible region was observed. When excited at 249 nm, an emission band at 513 nm (λem) appeared in the spectrum with a fluorescence quantum yield (Φ) of 7.0%. The absorption and fluorescence spectra

• previously reported electron-donating hexyloxy substituents. The addition pattern was experimentally investigated by 2D NMR, which was also supported by DFT calculations. The bistriazole product displayed fluorescence in the visible range with a fluorescence quantum yield of 7.0%. Finally, the developed

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

Synthesis and characterization of 1,2,3,4-naphthalene and anthracene diimides

• Adam D. Bass,
• Daniela Castellanos,
• Xavier A. Calicdan and
• Dennis D. Cao

Beilstein J. Org. Chem. 2024, 20, 1767–1772, doi:10.3762/bjoc.20.155

• has low fluorescence intensity (Φ = 0.006) [20], 7-Hex emits more efficiently with Φ = 0.41. Interestingly, 7-Ph has nearly no emission intensity, as evidenced by the low signal-to-noise ratio in the data and a near-zero quantum yield when excited at 400 nm. This fluorescence quenching is likely