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

• its physicochemical properties. Moreover, we tailored a fully earth-abundant photocatalytic system to achieve specifically CO2 reduction, optimizing efficiency and selectivity. By changing the conditions, we enhanced the turnover number (TON) of CO production from only 0.5 to more than 60 and the

• selectivity from 6% to 97% after four hours of irradiation at 420 nm. Further efficiency enhancement was achieved by adding 1,1,1,3,3,3-hexafluoropropan-2-ol, producing CO with a TON up to 230, although at the expense of selectivity (54%). Keywords: carbon monoxide selectivity; cobalt(II) complex; copper(I

• major components, fostering or dropping the efficiency. Thus, a rational design of novel molecular catalysts should consider an additional development of the whole system [7]. Moreover, it would be beneficial for future applications, if major efforts are focused on earth-abundant materials [8][9][10][11

Unprecedented synthesis of a 14-membered hexaazamacrocycle

• Anastasia A. Fesenko and
• Anatoly D. Shutalev

Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126

• 13 and 14 in Table 1). The experimental data described above were obtained using 50–141 mg of pyrazolopyrimidine 8. We demonstrated that, under the optimized conditions (1.5 equiv of N2H4·H2O, MeOH, reflux, 3 h), the reaction can be scaled up to gram quantities without any loss of efficiency and even

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

• a new class of FREAs called Y6. Y6 utilizes a ladder-type electron-deficient core-based central fused ring (dithienothiophen[3.2-b]pyrrolobenzothiadiazole) and achieved a remarkable efficiency of 16% in OSCs [26]. Building upon this breakthrough, Liu et al. blended Y6 with their polymer D18

• , resulting in an efficiency of 18% and marking a significant advancement in OSC research [27]. Zhou and co-workers synthesized Y6-type NFA acceptors, Qx12 and Qx13, by substituting Y6’s benzothiadiazole ring with a Qx moiety. Qx13 exhibited a stronger π–π interaction compared to Qx12, which facilitated

• ). The charge transfer efficiency and device performance of Qx33 was improved by aligning its LUMO energy level with the conduction band edge of the TiO2 nanoparticles. This strategic approach highlights the importance of optimizing energy level alignment for efficient charge transport in DSSCs [40

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

• coordinates of (0.664, 0.335)), an EQEmax of 3.32% and exciton utilization efficiency (EUE) of 47%. Keywords: ambipolar material; deep red fluorophore; hybridized local and charge transfer; naphthothiadiazole; OLED; organic light-emitting diode; Introduction Recently, organic fluorophores with efficient

• OLED realized a maximum external quantum efficiency (EQEmax) of 3.32% with an emission peak at 659 nm. Results and Discussion The designed TPECNz molecule was synthesized by a multistep reaction as described in Scheme 1. Initially, an Ullmann coupling reaction of bromo-TPE 1 and carbazole provided TPE

• orbital (HOMO) was delocalized over the Nz core and the attached carbazole moieties. There was an overlap between the HOMO and LUMO orbitals over the Nz fragment, which is likely to promote the LE component and consequently gives rise to a faster radiative decay and thus a higher luminescence efficiency

A series of perylene diimide cathode interlayer materials for green solvent processing in conventional organic photovoltaics

• Kathryn M. Wolfe,
• Shahidul Alam,
• Eva German,
• Fahad N. Alduayji,
• Maryam Alqurashi,
• Frédéric Laquai and
• Gregory C. Welch

Beilstein J. Org. Chem. 2023, 19, 1620–1629, doi:10.3762/bjoc.19.119

• new materials with studious strategies to negate these issues and contribute to the movement for the commercialization of OPVs [7][8][9]. Cathode interlayers (CILs) have been recently recognized as a key component to realize highly efficient OPVs. Indeed, the highest efficiency to date reported at

• detrimental to device performance and long-term stability. Second, efficiency is increased by tuning the frontier molecular orbitals to block holes by a deep highest occupied molecular orbital (HOMO) and by promoting electron cascade with a deep lowest unoccupied molecular orbital (LUMO). Third, CILs prevent

• ), and we also assessed the devices' external quantum efficiency (EQE), which can be seen in Figure 6a and 6b. To make the necessary adjustments to the PCE, integrated JSC (Supporting Information File 1, Figure S31) is computed for devices with their EQE values determined [31]. The estimated values of

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• initiator. Polystyrene of different molecular weights was obtained with low Mw/Mn and active chain ends [31]. Although a bicomponent initiating system is economical and practical, the traditional initiators have many problems such as the poor initiation efficiency. It is difficult to control the molecular

• achieved via a radical mechanism (Scheme 17). In comparison to the Pt-catalyzed system, the radical-induced hydrosilylation has a lower cost, better tolerance to coordinating functionalities, and yields products without metal residues, but its efficiency is inferior to transition-metal catalyzed methods

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• , tetrahydrofuran, methanol, toluene, hexane, and n-pentane were employed, in which the products in non-polar hydrocarbon solvents like hexane and n-pentane were obtained in excellent efficiency and enantioselectivity. Song et al. found that the chemoselective α-sulfenylation and β-thiolation of α,β-unsaturated

Functions of enzyme domains in 2-methylisoborneol biosynthesis and enzymatic synthesis of non-natural analogs

• Binbin Gu,
• Lin-Fu Liang and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 1452–1459, doi:10.3762/bjoc.19.104

• products that have been identified by GC–MS analysis and the synthesis of reference compounds [30][31]. Notably, 2MIBS also shows some substrate flexibility and can convert GPP into monoterpenes in vitro, albeit with less efficiency as compared to the conversion of 2-Me-GPP [24]. On the other hand, single

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• with >98% site-selectivity, in up to 98% yield and er = 96.5:3.5. Reactions involved a wide range of acyclic 1,1-disubstituted aryl olefins. Several C1-symmetric bidentate ligands derived from enantiomerically pure imidazolinium salts were examined for their efficiency. For example, a remarkable

• -naphthol moiety 193 afforded the highest yield and enantioselectivity. On protecting the hydroxy group in the ligand as methyl ether, the reaction efficiency decreased remarkably. However, on using NHC ligands without oxygen atom, such as analogues of 193, IMes, and SIMes, no conversion occurred. 2.8 C(sp2

One-pot nucleophilic substitution–double click reactions of biazides leading to functionalized bis(1,2,3-triazole) derivatives

• Hans-Ulrich Reissig and
• Fei Yu

Beilstein J. Org. Chem. 2023, 19, 1399–1407, doi:10.3762/bjoc.19.101

• substituent undergo a one-pot reaction with reasonable efficiency and furnished the expected 1,2,3-triazole derivative 7 in 61% yield under the approved conditions. Next, we turned our attention to the generation of divalent systems, starting with the reactions of 1,3- (8) and 1,2-bis(bromomethyl)benzene (11

Visible-light-induced nickel-catalyzed α-hydroxytrifluoroethylation of alkyl carboxylic acids: Access to trifluoromethyl alkyl acyloins

• Feng Chen,
• Xiu-Hua Xu,
• Zeng-Hao Chen,
• Yue Chen and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2023, 19, 1372–1378, doi:10.3762/bjoc.19.98

• of H2O were added to the reaction mixture [40] (Table 1, entry 6), but the addition of more water did not improve the reaction efficiency further (Table 1, entry 7). The structure of nickel catalysts played a significant role in the reaction efficiency. Switching the Ni catalyst to NiCl2(dtbbpy

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• are widespread as essential building blocks in various drugs, natural products, agrochemicals, and materials. Modern economy requires developing green strategies with improved efficiency and reduction of waste. Due to its atom and step-economy, the cross-dehydrogenative coupling (CDC) reaction has

• and regenerates the tert-butoxyl radical to complete the entire catalytic cycle. The formation of hydrogen bonds between the oxygen of the carbonyl group and the hydrogen of the 2,2,2-trifluoroethanol (TFE) reduces the activation energy of the radical reaction and improves the coupling efficiency. In

• application of this method still limited by sustainability, safety, and cost factors. Therefore, further development to shorten the reaction time, improve the reaction efficiency, and reduce energy consumption in an environmentally friendly, practical, and safe method for CDC will be a continuous process [131

Radical ligand transfer: a general strategy for radical functionalization

• David T. Nemoto Jr,
• Kang-Jie Bian,
• Shih-Chieh Kao and
• Julian G. West

Beilstein J. Org. Chem. 2023, 19, 1225–1233, doi:10.3762/bjoc.19.90

• functionalization of alkyl radicals, with successful synthetic reactions requiring efficiency and selectivity in both of these processes and inherent compatibility between each. Radical generation has benefitted from many general mechanistic approaches, including hydrogen atom transfer (HAT) [5], alkene addition [6

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• likely that the same recycling methods could be extended to the rest of the benzimidazole family. Benzimidazoles are being adopted in organic photoreductions [30], and have been shown to increase the efficiency of carbon dioxide reduction systems using ruthenium-based photocatalytic systems [48][72

Selective and scalable oxygenation of heteroatoms using the elements of nature: air, water, and light

• Damiano Diprima,
• Hannes Gemoets,
• Stefano Bonciolini and
• Koen Van Aken

Beilstein J. Org. Chem. 2023, 19, 1146–1154, doi:10.3762/bjoc.19.82

• byproducts, and increased efficiency in industrial processes. As such, this field of research is of great importance and interest to both academia and industry. This work showcases a sustainable and catalyst-free oxidation method for heteroatoms (e.g., S, P, and Se) using only air, water and light. An

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

• efficiency and selectivity of the reactions (vide infra, conPET section). Electrolytes have the potential to be i) aqueous-separated and recovered in batch, or ii) decreased, even ultimately eliminated by flow reactors as an engineering control. Regarding purely the chemical reactivity and scope of

• especially in the case of excited radical ions which oftentimes exhibit unusual wavelength dependencies on catalytic efficiency. Light source wavelengths/input powers (radiant flux is rarely reported) are quoted if available, readers are directed to the report in question for details. When not available, the

• , several polyhalogenated aromatics could be chemoselectively engaged at one C–X bond, even for 1-bromo-4-iodobenzene (1f). Apart from N-methylpyrrole, other substituted pyrroles, thiazine (4o), pyrazine (4p) and electron-rich benzenes (4q) were found to be suitable trapping reagents with varying efficiency

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

• harvesting efficiency of both the singlet and triplet excitons and thus a high quantum efficiency for the electroluminescence [13]. The TADF emission process involves the reverse intersystem crossing (rISC) from the triplet (T1) state to the emissive singlet (S1) state. A typical molecular structure motif

• analogous dyads recently, however, the delayed fluorescence lifetimes were much longer (2.0–14.4 μs) as compared to the current dyads [47]. TADF emitters with shorter delayed fluorescence lifetimes are suitable for fabrication of OLED devices, to suppress the efficiency roll-off effect. The photophysical

• 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

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

• , are studied as potential CO2 capture agents due to their unique molecular structures and high selectivity towards CO2. In this paper we have investigated binding efficiency of a number of cyclodextrins towards CO2. It is found that the crystal structure of α-cyclodextrin with CO2 has a 1:1

Linker, loading, and reaction scale influence automated glycan assembly

• Marlene C. S. Dal Colle,
• Manuel G. Ricardo,
• Nives Hribernik,
• José Danglad-Flores,
• Peter H. Seeberger and
• Martina Delbianco

Beilstein J. Org. Chem. 2023, 19, 1015–1020, doi:10.3762/bjoc.19.77

• ]. We wondered whether different glycan sequences were more sensitive to the linker structure. Less reactive donors might highlight differences in the linker nucleophilicity [25]. The aggregation of the growing glycan chains is conceivable to be connected to linker flexibility [18]. The efficiency of UV

• whether methanoloysis on resin could improve photocleavage efficiency. However, when we tested the same procedure on L1, target compound 5b was isolated in only 15% yield. These results strongly suggest that the two linkers perform differently depending on the glycan sequences. Conclusion Taken together

Synthesis of tetrahydrofuro[3,2-c]pyridines via Pictet–Spengler reaction

• Elena Y. Mendogralo and
• Maxim G. Uchuskin

Beilstein J. Org. Chem. 2023, 19, 991–997, doi:10.3762/bjoc.19.74

• hydrolysis could be a convenient tool for the synthesis of substituted 3-(2-oxopropyl)piperidin-4-ones 5. Using tetrahydrofuro[3,2-c]pyridine 4a as the model compound, we studied the effect of various Brønsted acids, temperature, concentrations, and the nature of the solvent on the efficiency of the reaction

Photoredox catalysis enabling decarboxylative radical cyclization of γ,γ-dimethylallyltryptophan (DMAT) derivatives: formal synthesis of 6,7-secoagroclavine

• Alessio Regni,
• Francesca Bartoccini and
• Giovanni Piersanti

Beilstein J. Org. Chem. 2023, 19, 918–927, doi:10.3762/bjoc.19.70

• feasible under these conditions, the observed reaction efficiency was poor (14–33% yield). However, on the 1H NMR spectrum, some unexpected signals were observed. The appearance of equilibrating species such as rotamers in the 1H NMR spectrum (see the variable-temperature NMR experiments in Supporting

• [98]. Reducing the substrate concentration increased efficiency while assisting in avoiding the oligomerization pathways (Table 1, entries 2 and 3). Higher photocatalyst loadings resulted in an increased yield (Table 1, entry 4). Control experiments showed that both the photocatalyst and light were

• essential for product production (Table 1, entries 6 and 7), despite the fact that the removal of base did not result in a significantly reduced efficiency (Table 1, entry 5). The regioselectivity outcome was explained by the relative stability of the intermediate radicals involved, with strong evidence of

Synthesis of aliphatic nitriles from cyclobutanone oxime mediated by sulfuryl fluoride (SO₂F₂)

• Xian-Lin Chen and
• Hua-Li Qin

Beilstein J. Org. Chem. 2023, 19, 901–908, doi:10.3762/bjoc.19.68

• control experiment, SO2F2 is essential for the reaction to proceed (Table 1, entry 2). Encouraged by the preliminary result, we then screened a large variety of conditions as shown in Table 1 in order to improve the efficiency of the transformation. The investigation of the solvent effect revealed that in

• %). Notably, the efficiency of this transformation was greatly impacted by the electronic effect on the aromatic rings of the olefins. Alkenes with electron-donating groups on their aromatic rings showed higher yields of the corresponding products as compared to those with electron-withdrawing groups (3af–ar

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

• to 2 h did not affect the yield of pyrimidine 9a (Table 1, entry 8). It is important to emphasize that the use of bases essentially impaired the efficiency of the method (Table 1, entries 9 and 10). Apparently, the addition of a basic reagent does not influence the main process and the decrease in

Honeycomb reactor: a promising device for streamlining aerobic oxidation under continuous-flow conditions

• Masahiro Hosoya,
• Yusuke Saito and
• Yousuke Horiuchi

Beilstein J. Org. Chem. 2023, 19, 752–763, doi:10.3762/bjoc.19.55

• structure raised the mixing efficiency of a gas–liquid reaction system, and it effectively accelerated the aerobic oxidation of benzyl alcohols to benzaldehydes under continuous-flow conditions. This reactor is a promising device for streamlining aerobic oxidation with high process safety because it is a

• -tube reactors or fixed bed reactors [17][18][19][20]. To maximize this advantage, the gas–liquid biphasic reaction must be controlled under continuous-flow conditions. This reaction requires high mixing efficiency to assure high mass transfer of the gas to the liquid phase and a consequent high

• high mixing efficiency throughout the reaction. This complex equipment complicates its versatile application for the scale-up and manufacturing, which leads to higher costs. To address this issue, we turned our attention to the use of porous material, which is widely used for exhaust gas treatment in

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

• 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

• us to undertake the current study. X-ray crystallography, UV–vis spectroscopy and cyclic voltammetry were applied to analyze the extent of π-electron conjugation and the efficiency of the particular donor–acceptor conjugation path in chromophores 5. Results and Discussion Synthesis The target