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

Thiophene/selenophene-based S-shaped double helicenes: regioselective synthesis and structures

• Mengjie Wang,
• Lanping Dang,
• Wan Xu,
• Zhiying Ma,
• Liuliu Shao,
• Guangxia Wang,
• Chunli Li and
• Hua Wang

Beilstein J. Org. Chem. 2022, 18, 809–817, doi:10.3762/bjoc.18.81

• obviously differ because of changes in their molecular configuration and equal to 2.86, 3.15, and 3.81 eV, respectively [27][28]. As the number of selenium atoms increases from DH-1 to DH-3, the fluorescence intensity (Figure S19 in Supporting Information File 1) and the fluorescence quantum yield (ΦF

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

• fluorescence quantum yield (ΦF) as well as radiative (kr) and non-radiative (knr) fluorescence decay rates (see Table 2). The ΦPF was typical for carbazole–pyrimidine TADF compounds [31][43][44], in the range of 0.01–0.07 and decreased for compounds with stronger acceptor units (see Figure S28b in Supporting

• profiles of the DF decay. Unfortunately, TADF decay rates were inaccessible. Similar emission decay transients were also estimated for RTP compounds 2a and 2d both at singlet and triplet emission peaks (see Figure S31 in Supporting Information File 1). The largest DF quantum yield, ranging from 0.34–0.49

• easily minimized, enabling rather efficient TADF. We have shown that electron-withdrawing substituents connected directly to the pyrimidine unit have a larger impact on TADF efficiency in comparison with those attached through a phenylene bridge. The largest delayed fluorescence quantum yield, ranging

Comparative study of thermally activated delayed fluorescent properties of donor–acceptor and donor–acceptor–donor architectures based on phenoxazine and dibenzo[a,j]phenazine

• Saika Izumi,
• Prasannamani Govindharaj,
• Anna Drewniak,
• Paola Zimmermann Crocomo,
• Satoshi Minakata,
• Leonardo Evaristo de Sousa,
• Piotr de Silva,
• Przemyslaw Data and
• Youhei Takeda

Beilstein J. Org. Chem. 2022, 18, 459–468, doi:10.3762/bjoc.18.48

• the D–A compound 1 compared to POZ-DBPHZ reflects the contribution of an additional donor to relaxation of the molecular geometry in the excited state. The photoluminescence quantum yield (ΦPL) of the D–A compound 1 is lower (0.13 in cyclohexane) than that of the D–A–D compound POZ-DBPHZ (0.33) [17

Effect of a twin-emitter design strategy on a previously reported thermally activated delayed fluorescence organic light-emitting diode

• Ettore Crovini,
• Zhen Zhang,
• Yu Kusakabe,
• Yongxia Ren,
• Yoshimasa Wada,
• Bilal A. Naqvi,
• Prakhar Sahay,
• Tomas Matulaitis,
• Stefan Diesing,
• Ifor D. W. Samuel,
• Wolfgang Brütting,
• Katsuaki Suzuki,
• Hironori Kaji,
• Stefan Bräse and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2021, 17, 2894–2905, doi:10.3762/bjoc.17.197

• nm compared to that of ICzTRZ at 475 nm and showed a comparable photoluminescence quantum yield of 57.1% in a 20 wt % CzSi film versus 63.3% for ICzTRZ. The emitter was then incorporated within a solution-processed organic light-emitting diode that showed a maximum external quantum efficiency of 8.4

• % doped CzSi film of DICzTRZ emits in the blue at 488 nm and shows a photoluminescence quantum yield of 57.1%. The ΦPL of DICzTRZ is slightly lower than that of ICzTRZ (63% under N2 [14]), in line with its lower computed oscillator strength. DICzTRZ shows both prompt and delayed fluorescence, with a τp

• , b) EL spectra and c) current density-voltage-luminance properties. Device efficiency simulation of the fabricated OLEDs depicting the variation in EQE with varied PL quantum yield (vertical axis) and anisotropy factor (horizontal axis). The predicted EQEs are indicated with pink and blue rectangular

Photophysical, photostability, and ROS generation properties of new trifluoromethylated quinoline-phenol Schiff bases

• Inaiá O. Rocha,
• Yuri G. Kappenberg,
• Wilian C. Rosa,
• Clarissa P. Frizzo,
• Nilo Zanatta,
• Marcos A. P. Martins,
• Isadora Tisoco,
• Bernardo A. Iglesias and
• Helio G. Bonacorso

Beilstein J. Org. Chem. 2021, 17, 2799–2811, doi:10.3762/bjoc.17.191

• attributed to a greater electronic conjugation provided by the imine function present in the molecules of the series 3. Photostability and singlet oxygen quantum yield (ΦΔ) assays In order to be efficient for applications in photobiology, organic dyes must be stable when subjected to light irradiation for

• -aminoquinolines and salicylaldehydes and an easy purification methodology with yields of up to 91%. Photophysical experiments with the derivatives exhibited common transitions in these heterocycle units and corroborated the aromatic structures and good fluorescence quantum yield values for all compounds

• −5 M). Photooxidation rate constants and singlet oxygen quantum yield of compounds 3aa–fa and 3bb–be in DMSO solution. Supporting Information Supporting Information File 270: NMR spectra of the compounds, IR spectra, crystallographic data, photophysical and singlet oxygen spectra of new structures

Synthesis and investigation on optical and electrochemical properties of 2,4-diaryl-9-chloro-5,6,7,8-tetrahydroacridines

• Najeh Tka,
• Mohamed Adnene Hadj Ayed,
• Mourad Ben Braiek,
• Mahjoub Jabli and
• Peter Langer

Beilstein J. Org. Chem. 2021, 17, 2450–2461, doi:10.3762/bjoc.17.162

• given in Figure 4 and Figure 5, respectively. In addition, their plots of fluorescence intensities against absorbances are shown in Figure 6A and 6B. The tetrahydroacridine derivative 4b gave the highest fluorescence quantum yield of 8.2%. In order to elucidate the experimental observations and to

Chemical approaches to discover the full potential of peptide nucleic acids in biomedical applications

• Nikita Brodyagin,
• Martins Katkevics,
• Venubabu Kotikam,
• Christopher A. Ryan and
• Eriks Rozners

Beilstein J. Org. Chem. 2021, 17, 1641–1688, doi:10.3762/bjoc.17.116

• emission intensity (dependent on the sequence context) upon hybridization with complementary DNA and RNA [145]. Another analogue, 5,6-BenzopC (Figure 10) had high quantum yield and superior base pairing properties, but its fluorescence was completely quenched upon hybridization with DNA and RNA [146

2,4-Bis(arylethynyl)-9-chloro-5,6,7,8-tetrahydroacridines: synthesis and photophysical properties

• Najeh Tka,
• Mohamed Adnene Hadj Ayed,
• Mourad Ben Braiek,
• Mahjoub Jabli,
• Noureddine Chaaben,
• Kamel Alimi,
• Stefan Jopp and
• Peter Langer

Beilstein J. Org. Chem. 2021, 17, 1629–1640, doi:10.3762/bjoc.17.115

• , including the maximum of absorption and emission, fluorescence quantum yield, stokes shift, onset of the absorption wavelengths and optical band gap are summarized in Table 3. Aiming to understand the impact of substituents at arylethynyl groups, spectra of diversely substituted tetrahydroacridines were

• relative method using quinine sulfate [70]. Tetrahydroacridine derivative 4g containing an electron-donating methoxy substituent gave the highest fluorescence intensity as shown in Figure 3 and a quantum yield of 20%. DFT studies The arylethynyl substituents showed an impact on the absorption and emission

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

• [120]. At the same time, in vivo experiments have shown the high efficiency of low-molecular-weight isoindigo 71 in oxygen sensitization for cancer therapy [121]. Therein, a high value (84%) of the singlet oxygen quantum yield was obtained. Conclusion To summarize, it can be concluded that isoindigo is

Design, synthesis and photophysical properties of novel star-shaped truxene-based heterocycles utilizing ring-closing metathesis, Clauson–Kaas, Van Leusen and Ullmann-type reactions as key tools

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2021, 17, 1374–1384, doi:10.3762/bjoc.17.96

• ]. More interestingly, the high fluorescence quantum yield as well as the excellent photoluminescence quantum efficiency in addition to extraordinary thermal stability are the most significant characteristics of these systems. Interestingly, this versatile C3-symmetric aromatic framework can also formally

A new glance at the chemosphere of macroalgal–bacterial interactions: In situ profiling of metabolites in symbiosis by mass spectrometry

• Marine Vallet,
• Filip Kaftan,
• Veit Grabe,
• Fatemeh Ghaderiardakani,
• Simona Fenizia,
• Aleš Svatoš,
• Georg Pohnert and
• Thomas Wichard

Beilstein J. Org. Chem. 2021, 17, 1313–1322, doi:10.3762/bjoc.17.91

• . mutabilis germlings were stained with SYBR Gold, a sensitive probe forming a complex with DNA with high fluorescence quantum yield [36]. In the axenic callus-like form, the nuclei of algal cells and the bacterial cells accumulated around the rhizoidal tissue and exhibited the specific fluorescence after

Synthesis of 10-O-aryl-substituted berberine derivatives by Chan–Evans–Lam coupling and investigation of their DNA-binding properties

• Peter Jonas Wickhorst,
• Mathilda Blachnik,
• Denisa Lagumdzija and
• Heiko Ihmels

Beilstein J. Org. Chem. 2021, 17, 991–1000, doi:10.3762/bjoc.17.81

• deactivation of the excited state by conformational changes, e.g., torsional relaxation [42][43]. Since the fluorescence quantum yield of the parent berberine (1a) does not correlate well with the viscosity of the medium [40], it was concluded that the weak light-up effect in glycerol is mainly caused by the

• suppressed rotation about the Ar–O bond. Nevertheless, as the emission quantum yield of the derivatives 5a–e still remained low, even at high viscosity of the medium, there obviously exist additional relaxation pathways in the excited state, most likely a photo-induced electron transfer (PET) from the 10

• -aryl substituent to the berberine chromophore. The latter has been shown to operate also in resembling cationic, biaryl-type dyes [42][43]. Along the same lines, the low intrinsic emission quantum yield of the parent berberine (1a) has been suggested to result from an internal charge transfer (ICT