Facile access to pyridinium-based bent aromatic amphiphiles: nonionic surface modification of nanocarbons in water

• Lorenzo Catti,
• Shinji Aoyama and
• Michito Yoshizawa

Beilstein J. Org. Chem. 2024, 20, 32–40, doi:10.3762/bjoc.20.5

• similar to AA [12][13], indicating self-assembly via the hydrophobic effect and π-stacking interactions (Figure 3a,b). The self-assembly in water was further supported by UV–visible analysis, displaying slight red-shifts of the anthracene absorption bands relative to the spectrum in methanol (Δλmax = +3

• the self-assembly of in average six PA-CH3 amphiphiles into a small aromatic micelle (Figure 3g). In a similar way, the generation of micelles (PA-OCH3)n, (PA-OH)n, and (PA-Im)n was confirmed via NMR, UV–visible, and DLS analyses upon dissolution of the corresponding amphiphiles in water (Figure 3c,d

• H2O (2.7 mL), the suspension was sonicated with a probe sonicator (40 kHz, 150 W, 10 min), centrifuged (16,000g, 10 min), and then filtrated (200 nm pore-size membrane filter) to yield a clear brown solution containing host–guest composite (PA-OCH3)n·(C60)m. The UV–visible analysis clearly showed new

Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes

• Nedra Touj,
• François Mazars,
• Guillermo Zaragoza and
• Lionel Delaude

Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145

• stretching vibration of the S=C–S− group, another strong absorption was clearly visible in the IR spectra of CAAC·CS2 betaines 4a–c. This second most intense band was observed around 1550 cm−1 (Table 2). It probably originated from the asymmetric stretching of the aldiminium group, in line with similar high

Beyond n-dopants for organic semiconductors: use of bibenzo[d]imidazoles in UV-promoted dehalogenation reactions of organic halides

• Kan Tang,
• Megan R. Brown,
• Chad Risko,
• Melissa K. Gish,
• Garry Rumbles,
• Phuc H. Pham,
• Oana R. Luca,
• Stephen Barlow and
• Seth R. Marder

Beilstein J. Org. Chem. 2023, 19, 1912–1922, doi:10.3762/bjoc.19.142

• (Figure 4a) show significant spectral evolution within the first 1 ps following photoexcitation at 350 nm in MeCN. The (negative) bleach feature at 450 nm and photoinduced absorption (PIA) peaking at 775 nm transform into a broad PIA spanning the visible wavelengths with a notable isosbestic point at 600

• -DMBI)2 with a broad PIA spanning the visible wavelengths, which may suggest that the initial evolution observed in the (N-DMBI)2 occurs within our instrument response. In toluene, the signal amplitude at 5 ns for (Cyc-DMBI)2 is significantly smaller than that of the (N-DMBI)2 and 96% of the signal

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

• the solutions of the compounds showed non-structured emission peaks in the visible region, which are attributed to ICT emission. The PL intensities of the solutions of the compounds are enhanced after deoxygenation, which is indicative of TADF. The photoluminescence quantum yields and TADF properties

• 10 000 cd m−2, electroluminescence ranging from blue to yellow, maximum current of 15 cd/A and higher EQE than 7%. Pyridine-3,5-dicarbonitrile-based TADF materials exhibit different visible light emission spectra (Figure 1). Recently, Chen and Lu reported two new orange-red/red TADF emitters composed

• and visible regions. Emission spectra of solutions and films were recorded using an Edinburgh Instruments FLS980 spectrometer, enabling a detailed investigation of the emission behavior of compounds. The choice of toluene, THF, and CHCl3 as solvents in our study was based on their different polarities

Controlling the reactivity of La@C₈₂ by reduction: reaction of the La@C₈₂ anion with alkyl halide with high regioselectivity

• Yutaka Maeda,
• Saeka Akita,
• Mitsuaki Suzuki,
• Michio Yamada,
• Takeshi Akasaka,
• Kaoru Kobayashi and
• Shigeru Nagase

Beilstein J. Org. Chem. 2023, 19, 1858–1866, doi:10.3762/bjoc.19.138

• and visible–near infrared spectroscopy. The reaction of La@C2v-C82 with alkyl halides using the same conditions showed no consumption of La@C2v-C82, indicating that the reactivity of La@C2v-C82 toward alkyl halides was effectively increased by one-electron reduction. Single-crystal X-ray diffraction

• °C for 2 h (Scheme 1). Figure 1 depicts the changes in the visible–near infrared (vis–NIR) absorption spectra during the reaction, showing gradual changes with isosbestic points. Since the electrolyte interferes with the high-performance liquid chromatography (HPLC) separation and anionic species may

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• -anion catalysis under visible light irradiation, as depicted in Scheme 9. Subsequent investigations revealed that redox-active esters 3 and Katritzky salts 15 derived from amino acids could be effectively employed in decarboxylative/deaminative cross-coupling reactions [15]. These reactions enabled the

• -heterocycles. Recently, independent research groups led by Li, Yang, and Patureau separately disclosed a novel approach to 3,3-disubstituted oxindoles 43 through an iodide/phosphine-catalyzed visible-light-mediated decarboxylative radical cascade cyclization of N-arylacrylamides 42 (Scheme 18) [35][36

• hydrogenation or hydrogen transfer [40], electrocatalysis coupled with water oxidation [41], and sustained visible-light-induced photocatalysis [42]. Among the different strategies available, the use of a mild photocatalytic process involving hole-driven hydrogen transfer with hydrogen donors or hole scavengers

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

• dichloromethane at 1 mg mL−1 concentration. Molecular absorption spectroscopy Molecular absorption spectra were recorded on Agilent Cary 100 conc UV–visible spectrophotometer between the range of 200 and 800 nm in quartz cuvettes. Stock solutions of the compounds were prepared in spectroscopic grade DMSO at 5

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

• 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

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

• , particularly when they are applied as emitters in organic light-emitting diodes (OLEDs) [19]. Therefore, with such a constrained number of efficient emitters, the current advance of DR/NIR OLEDs largely trails behind the visible light emission OLEDs [20][21]. So far, remarkable efforts have been made in

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

• cation and crown ether pocket, dimerisation of the crown porphyrin molecule would occur. The dimerisation led to interesting changes in the visible, NMR, ESR, and emission spectral features. Further developments by Camilleri, Gunter, Boitrel, and Osuka focused on the exploitation of meso-crowned

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

• NMR spectroscopy, mass spectrometry, and elemental analysis. See Supporting Information File 1 for full synthetic and characterization details. Optical properties Using UV–visible spectroscopy, the optical properties for PDIN-FB, PDIN-B, CN-PDIN-FB, and CN-PDIN-FB in both solution and film form were

• group impacts the shape of the UV–visible film spectra, leading to ill-defined 0 → 0, 0 → 1, and 0 → 2 transitions, while those without a nitrile group exhibit well-defined 0 → 0 and 0 → 1 transitions. Complex aggregation of these compounds is evident, and no clear indication of H- or J-aggregation can

• filter. The absorbance of each saturated solution was measured with a UV–visible spectrophotometer to determine the concentration using the Beer–Lambert law and the previously determined molar extinction coefficients. PDIN-FB reached a saturated solution at a concentration at 8.4 mg/mL, PDIN-B a

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

• ., Zibo 256401, China 10.3762/bjoc.19.98 Abstract A visible-light-induced nickel-catalyzed cross coupling of alkyl carboxylic acids with N-trifluoroethoxyphthalimide is described. Under purple light irradiation, an α-hydroxytrifluoroethyl radical generated from a photoactive electron donor–acceptor

• direct conversion of carboxylic acids to ketones is an important chemical transformation [31][32][33][34][35][36][37][38]. However, to the best of our knowledge, this protocol has not been used for the synthesis of fluoroalkylated ketones so far. Very recently, we have developed a visible-light-induced

• might be feasible. Herein, we disclose a visible-light-induced nickel-catalyzed cross-coupling of alkyl carboxylic acids with N-trifluoroethoxyphthalimide to deliver trifluoromethyl aliphatic acyloins under mild conditions (Scheme 1d). Furthermore, this platform bypasses the need for exogenous

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

• assigned to singlet locally excited fluorescence (1LE) from the benzoguanidine donor ligand. The second high-energy PL component at 470 nm becomes visible only after a long-time delay (720 ms, see Figure 5 black profile), therefore, we ascribed it to a phosphorescence from a higher lying 3LE state

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

• into a carbon-centered radical B which then combines with 2-methylpyridine to obtain radical intermediate C. Oxidation of intermediate C by radical A then furnishes the product. Photocatalyzed CDC reactions In recent years, visible-light-driven photocatalytic processes have been considered influential

• -dicarbonyl compounds. Rare earth-metal-catalyzed CDC reaction. Visible-light-driven CDC of cycloalkanes with benzazoles. Photoinduced alkylation of quinoline with cyclic ethers. Photocatalyzed CDC reactions between α-C(sp3)–H bonds of ethers and C(sp2)–H bonds of aromatics.

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

• ) 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

• visible and near IR regions [11][12][13][14]. Similarly, simple quinoxaline-based heterocycles have shown their potential as photosensitizers to induce toxicity in a single cell green algae such as Chlamydomonas reinhardtii [15] and also displayed efficacy against Mycobacterium tuberculosis and other

• Soret bands between 439–442 nm and four Q-bands between 526 and 642 nm (Figure 3). In contrast, UV–visible spectra of zinc(II) benzo[f]chromeno[2,3-h]quinoxalinoporphyrins 14–16 showed broadened Soret bands with slight splitting between 445–450 nm and two Q-bands at ≈566 and 606 nm (Figure 4). All the

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

• 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

• system using a benzimidazole sacrificial donor. As we have discussed, examples of recycling benzimidazoles already exist which makes them excellent candidates for donor recycling. In contrast to those developed for water splitting, one of the first visible light-driven Z-scheme for carbon dioxide

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

• increase the concentration from 0.06 M to 0.6 M (Table 1, entry 7) maintaining approximately the same reaction time, while further concentration increase resulted in substantially slower kinetics (see Supporting Information File 1, Table S2). When performing the reaction in the dark or under visible light

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

• generation of reactive intermediates for both oxidative and reductive processes via photon activation of a catalyst. Although this represents a significant step towards chemoselective and, more generally, sustainable chemistry, its efficacy is limited by the energy of visible light photons. Nowadays

• conditions are available via PRC (vide infra). However, even if PRC provides elegant methods to circumvent these issues, it comes with its own set of limitations. In particular, the accessible energy for photocatalytically-driven transformations is generally limited by the energy of a single visible light

• remain inert to direct photoredox activation powered by visible light [12]. Irradiation with UV photons that intrinsically possess higher energy, however, is generally unfavorable due to the high expense and thermal footprint of the reactors. Although most organic molecules directly absorb photons in the

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

• photocatalyst. Keywords: decarboxylative cyclization; DMAT; ergot alkaloids; photoredox catalysis; radicals; Introduction Visible-light photoredox catalysis is rapidly changing the way organic chemists approach the design and synthesis of molecules by offering new synthetic disconnection opportunities that

• of all ergot alkaloids, specifically the decarboxylative cyclization of DMAT, is still a puzzle even though a radical mechanism has been proposed (Figure 1a) [72][73]. Results and Discussion Herein, we propose that visible light irradiation of the cationic iridium photocatalyst Ir[dF(CF3)ppy]2(dtbbpy

• visible-light irradiation of the photoredox catalyst [Ir(dF(CF3)ppy)2(dtbpy)]PF6 to access the excited state *[Ir(dF(CF3)ppy)2(dtbpy)]PF6, which can trigger SET oxidation of 8. Rapid decarboxylation leads to α-amino radical V (and the reduced photocatalyst), which is intercepted by the pendant double bond

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

• ], Liu [35], and Yang [36] achieved similar transformations through visible-light photocatalysis. In addition, Guo [37][38] improved the protocol by using low-cost nickel and iron catalysts. However, most of these advancements mainly relied on the excellent redox potential manipulation of cyclic oxime

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

• 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

• motifs in rotaxane-based polymers has also provided interesting properties which can be employed in some specific implementations. α-Cyclodextin-based polyrotaxanes 2 having trithiocarbonate stopper groups with an adjacent phenyl group were employed for the construction of visible light-degradable

• supramolecular gels (Figure 2a) [52]. Upon irradiation using a UV-light-emitting diode (LED) and a visible LED as sources, the reversible cleavage of the trithiocarbonate stoppers was accomplished, thus allowing the dethreading [53] of the wheels to take place by the shuttling of the macrocycles along the thread

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

• mol·L−1 hydrochloric acid solution, heated at 70 °C, cooled and filtered. The filtrate was slowly evaporated in air (about 10 days) to obtain colorless crystals. Ultraviolet–visible absorption and fluorescence spectroscopy An aqueous solution of TMeQ[6] and G@TMeQ[6] at 3.0 × 10−5 mol L−1 was prepared

• . The host–guest interaction between TMeQ[6] and G was investigated using a UV-2700 dual-beam ultraviolet–visible (UV–vis) spectrophotometer and Varian Cary Eclipse fluorescence spectrophotometer at room temperature [41]. At U = 550 V, slit = 5/5, different concentrations of G were added to the TMeQ[6

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

• = 844 000 M−1 cm−1 at 573 nm). A pair of enantiomers, (M,M)- and (P,P)-configuration was revealed by single crystal X-ray diffraction and optically pure samples of 125 were isolated by chiral HPLC. Meanwhile, a record high electronic circular dichroism (ECD) signal in the visible spectral range (Δε

Photocatalytic sequential C–H functionalization expediting acetoxymalonylation of imidazo heterocycles

• Deepak Singh,
• Shyamal Pramanik and
• Soumitra Maity

Beilstein J. Org. Chem. 2023, 19, 666–673, doi:10.3762/bjoc.19.48

• chemodivergent formation of C-3 ethoxycarbonylmethylated and hydroxyalkylated IPs under visible light using water or alcohol as the source of the oxygenated group under degassed conditions [22]. However, all these photochemical methods require the usage of a substantial amount of base, the preactivation with a

Direct C2–H alkylation of indoles driven by the photochemical activity of halogen-bonded complexes

• Martina Mamone,
• Giuseppe Gentile,
• Jacopo Dosso,
• Maurizio Prato and
• Giacomo Filippini

Beilstein J. Org. Chem. 2023, 19, 575–581, doi:10.3762/bjoc.19.42

• substrates [13][14][15][16][17][18]. In this approach, an electron acceptor substrate (“A”) and a donor molecule (“D”) interact to form a new aggregate defined as EDA complex (Figure 1a). Although the two molecular entities might not directly absorb visible light, the newly formed complex usually presents a

• charge transfer state which results in a bathochromic shift of the absorption towards the visible range [19][20]. Upon light irradiation, the EDA complex may undergo an intramolecular single-electron-transfer (SET) process to produce a radical ion pair (D•+, A•−). To avoid the occurrence of a back

• ambient temperature and under visible-light irradiation. Interestingly, this method employs 1,4-diazabicyclo[2.2.2]octane (DABCO) as sacrificial donor in the EDA complex formation with 2. To test the feasibility of our design plan, we focused on the reaction between 3-methylindole (1a, 2 equiv) and α