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Search for "visible" in Full Text gives 652 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Synthesis of optically active folded cyclic dimers and trimers
Beilstein J. Org. Chem. 2025, 21, 1603–1612, doi:10.3762/bjoc.21.124
- simple SiO2 column chromatography. In addition, they were purified using a recyclable high-performance liquid chromatography (HPLC) to remove unidentified impurities to obtain (Sp)-6 and (Sp)-7 in 16% and 3% isolated yields, respectively. The ultraviolet–visible (UV–vis) absorption spectra and normalized
Thermodynamic equilibrium between locally excited and charge transfer states in perylene–phenothiazine dyads
Beilstein J. Org. Chem. 2025, 21, 1577–1586, doi:10.3762/bjoc.21.121
- featuring high photostability and strong visible absorption. Perylene–phenothiazine (Pe–PTZ) derivatives have been previously investigated for their excited-state dynamics [15]. Incorporating additional electron-donating groups such as triphenylamine (TPA) onto the PTZ core is expected not only to enhance
General method for the synthesis of enaminones via photocatalysis
Beilstein J. Org. Chem. 2025, 21, 1535–1543, doi:10.3762/bjoc.21.116
- ]. Thus, the use of visible light as an energy source provides more efficient chemical transformations and minimize the use of harmful reagents, the generation of waste and the consumption of energy, fulfilling several principles of Green Chemistry and promoting greener opportunities for organic synthesis
- [37][38]. In this context, the reactivity of enaminones under visible-light-mediated reaction conditions has attracted significant attention [39]. However, it is rather surprising that a photocatalytic approach for the synthesis of enaminones has yet to be explored. Herein, we report the first light
- while 3-iodochromone failed to provide the desired enaminone 9a (Table S7, Supporting Information File 1). Control experiments including the reaction in the absence of visible-light or photocatalyst, showed no product formation (Table 1, entries 16 and 17). Interestingly, the yield of 9a dropped to 30
Azobenzene protonation as a tool for temperature sensing
Beilstein J. Org. Chem. 2025, 21, 1528–1534, doi:10.3762/bjoc.21.115
- calculations revealed that a second acid molecule significantly enhances protonation, prompting further investigation into the reaction stoichiometry. Upon protonation of 3, the n → π* transition disappears and the π → π* transition red-shifts from 358 nm to 502 nm (Figure 1B), resulting in a visible color
Highly distinguishable isomeric states of a tripodal arylazopyrazole derivative on graphite through electron/hole-induced switching at ambient conditions
Beilstein J. Org. Chem. 2025, 21, 1496–1507, doi:10.3762/bjoc.21.112
- -resolution images, and an example is shown in Figure 2d. The resonances in the 2D-FFT are originated from the moiré pattern of the super-lattice. Two distinct orientations are visible in the 2D-FFT. The 3-fold orientation of islands suggests that the molecular lattices are oriented with respect to the
- visible in large-area STM images as well. A super-periodic pattern is visible at low resolution, and the periodicity (≈6.1 nm) matches with the AFM measurements. Additional STM images of the ultra-thin film of FNAAP at different resolutions are provided in Supporting Information File 1, section 5. Next
- calculations assume a commensurate hexagonal lattice. The graphite lattice directions are marked by the 3-black arrows. The unit cell parameters of optimized geometry (a = 1.968 nm, b = 1.968 nm and γ = 120°) match well with the experiments. The microscopic arrangement of the molecules is clearly visible. It
Photoredox-catalyzed arylation of isonitriles by diaryliodonium salts towards benzamides
Beilstein J. Org. Chem. 2025, 21, 1480–1488, doi:10.3762/bjoc.21.110
- . Control experiments, Figure S20). Conclusion In conclusion, a novel synthetic methodology for the preparation of benzamides from isonitriles and diaryliodonium salts has been proposed utilizing visible-light photoredox ruthenium-based catalysis. Both symmetrical and unsymmetrical diaryliodonium salts were
Advances in nitrogen-containing helicenes: synthesis, chiroptical properties, and optoelectronic applications
Beilstein J. Org. Chem. 2025, 21, 1422–1453, doi:10.3762/bjoc.21.106
- , or selenium enables spectral tuning across the visible to near-infrared range, improved photostability, and dual-state emissive behavior. In parallel, significant progress in synthetic methodologies – including enantioselective catalysis, electrochemical cyclizations, and multicomponent reaction
- chiroptical retention upon nitrogen incorporation. Qian’s group developed a series of azahelicenes 15a–d through Bischler–Napieralski cyclization [28]. Notably, compound 15b displayed a high interconversion barrier of 36.0 kcal mol−1, enabling enantiomeric resolution. All compounds exhibited visible-range
- %, representing the highest reported values for thermally activated delayed fluorescence (TADF) emitters operating above 650 nm. Shortly thereafter, Wang’s group reported a related series of B,N-containing compounds 38a–c, which displayed pronounced chiroptical activity in the visible region [53]. These compounds
Oxetanes: formation, reactivity and total syntheses of natural products
Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101
- performing the reaction under visible light irradiation, or coupling the reaction to other light-induced processes to produce new classes of products. In 2018, Aitken and co-workers reported a synthesis of previously unknown tricyclic 4:4:4 oxetanes 73 through a photochemical triple cascade reaction starting
- , γ-H transfer and Paternò–Büchi reaction. In 2020, two highly similar methodologies based on a visible-light-mediated Paternò–Büchi reaction between simple alkenes 77 and α-ketoesters 78 were reported independently and shortly after one another (Scheme 21) [61][62]. They both use blue light for
- promoted by visible light at room temperature, requires no protecting atmosphere or additives, and the resulting polysubstituted oxetanes are obtained in moderate to good yields. Additional advantages include scalability and high chemoselectivity as various functional groups were tolerated, including
Recent advances in amidyl radical-mediated photocatalytic direct intermolecular hydrogen atom transfer
Beilstein J. Org. Chem. 2025, 21, 1306–1323, doi:10.3762/bjoc.21.100
- modified. In recent years, photocatalysis has been widely adopted due to its green and efficient nature [45][46][47][48][49][50][51]. The generation of amidyl radical is implemented by HRP. Six different methods (Figure 2c), which have been developed for visible-light mediated reactions, could generate
- (SET) process by the cleavage of the N–O bond; (c) direct homolytic cleavage of weak N–S or N–X bonds in HRP initiated in the presence of visible light; (d) the intersystem crossing (ISC) of S1 to T1 state directly from the amide anion. This review is organized by bond cleavage type, offering a deep
- demonstrated the homolytic cleavage of the N–O bond using N-(tert-butyl)-O-(1-phenylvinyl)-phenylhydroxyamide as a HAT reagent [78][79]. This compound was capable of initiating the formation of amidyl radicals through visible light activation. Although their controlled experiments showed that this method was
Recent advances and future challenges in the bottom-up synthesis of azulene-embedded nanographenes
Beilstein J. Org. Chem. 2025, 21, 1272–1305, doi:10.3762/bjoc.21.99
- | values of helicenes in the visible range. Miscellaneous reactions: The scope of reactions that can be used as the final fusion step when azulene-containing precursors are employed is not limited to those described above. A synthetic strategy involving condensation followed by the reaction of the
- planar π-structures and exhibit weak azulene-like S0→S1 transition absorptions in the visible regions. Single-crystal ribbons of 176 exhibit p-type semiconducting behaviour with hole mobilities of up to 0.29 m2 V−1s−1. Typical Cadogan products can be obtained when the NO2 group is localized in the
Recent advances in oxidative radical difunctionalization of N-arylacrylamides enabled by carbon radical reagents
Beilstein J. Org. Chem. 2025, 21, 1207–1271, doi:10.3762/bjoc.21.98
- quinolinone products. Beyond electrochemical protocols, photochemical activation – particularly visible-light photoredox catalysis – has become a powerful and sustainable strategy for generating carbon radicals under mild conditions. In 2023, Fan’s group discovered a radical cyclization of N-arylacrylamides
- radical then reacts with acrylamide to yield the desired product 37. As shown in Scheme 21, a visible light-induced trifluoromethylation/arylation using Umemoto’s reagent for the synthesis of trifluoromethylated oxindole derivatives was reported by Huang and Zhang’s group in 2021 [13]. This method is
- ), the process involves the homolytic cleavage of Umemoto's reagent 39 under visible light irradiation, releasing a trifluoromethyl radical 42. The radical then adds to the double bond of N-arylacrylamide, forming intermediate radical 43. Subsequently, this intermediate undergoes intramolecular
Gold extraction at the molecular level using α- and β-cyclodextrins
Beilstein J. Org. Chem. 2025, 21, 1116–1125, doi:10.3762/bjoc.21.89
- expected tridimensional CD-MOF in the presence of KAuBr4 in aqueous solution. Instead, they self-assembled into unidimensional threads that aggregated into superstructures and formed, in less than one minute, needle-shaped crystals visible to the naked eye. In these crystals, the molecules of α-CD stacked
Recent advances in synthetic approaches for bioactive cinnamic acid derivatives
Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85
- (2022) investigated the visible-light-mediated amidation of cinnamic acid (7) by using ethyl 2-diazoacetate and acetonitrile to give its corresponding amide 103 in excellent yield (Scheme 32) [29]. The reactive free carbene 104 was released upon light exposure of the diazo ester leading to the nitrilium
- proceeding via C–N-bond cleavage of the oxidized tertiary amine 116 (Scheme 35) [70]. Cinnamic acid (7) was activated by forming the acyl radical 118 after −OPyf group cleavage from 117. Recently, Li and co-workers (2024) studied visible-light-mediated FeCl3-catalyzed reductive transamidation of nitro
Biobased carbon dots as photoreductants – an investigation by using triarylsulfonium salts
Beilstein J. Org. Chem. 2025, 21, 1024–1030, doi:10.3762/bjoc.21.84
- ); triarylsulfonium salts; visible light; Introduction Carbon dots (CDs) are a class of zero-dimensional carbon-based semiconducting nanoparticles bearing on the surface a wide range of functional groups, such as carboxylic acids, alcohols, and amines, that garnered significant attention in the last decade among the
- their size, surface defects, and functional groups, which can be engineered to tune their optical properties. Accordingly, their emission spans a broad range of wavelengths, from ultraviolet to the visible region, allowing for the potential application in an impressive range of applications, such as
- biocompatibility. The electrochemical properties of such materials have been then evaluated by cyclic voltammetry (CV). For all the properties mentioned above, CDs emerged as low-cost and sustainable photocatalysts. Indeed, upon visible-light irradiation, the generated excited state CD* can operate as either
On the photoluminescence in triarylmethyl-centered mono-, di-, and multiradicals
Beilstein J. Org. Chem. 2025, 21, 964–998, doi:10.3762/bjoc.21.80
- , there is a lack of understanding of why the absorption and photoluminescence of D3 symmetrical triphenylmethyl radicals are so weak in the visible spectrum. While it is understood that the functionalization with donor moieties breaks the D3 symmetry, the ϕ varies greatly among different donors and also
- Gomberg (see TTM and PTM in Figure 1a) [31]. Gomberg’s radical emits light in the green region of the visible spectrum, which is shifted bathochromically by substituting the ortho- and para-positions of the trityl phenyl rings with halogens. However, all symmetrical halo-trityl radicals exhibit low ϕ
- bromine substitution decreases the spin–lattice relaxation time T1 of the radical electron. This is due to increased spin–orbit coupling in the brominated species. By contrast, the phase memory time Tm becomes longer for successively brominated radicals, visible from the concurrent spectral broadening in
Study of tribenzo[b,d,f]azepine as donor in D–A photocatalysts
Beilstein J. Org. Chem. 2025, 21, 935–944, doi:10.3762/bjoc.21.76
- absorption profile in the visible region, ii) a long lifetime of the excited states, and iii) balanced redox potentials in both the ground and excited states [7]. In 2018, Zeitler and her collaborators conducted an innovative and in-depth study on modulating the photochemical properties of a family of donor
- 6a, we observed a blue-shifted absorption profile due to the break of the conjugation in sulfur-based acceptors. Compounds 4a and 6a presented a similar absorption profile, while molecule 5a showed a red-shifted spectrum tailing up to the visible region (Figure 2a). The lack of a significant charge
- Supporting Information File 1, Table S3). As we expected, due to the blue-shifted absorption presented in molecules 4a and 6a, it was impossible to excite them under visible light (400 nm). Gratifyingly, PC 5a delivered product 8 with a promising 63% NMR yield. Next, we compare the photocatalytic behavior of
Recent advances in controllable/divergent synthesis
Beilstein J. Org. Chem. 2025, 21, 890–914, doi:10.3762/bjoc.21.73
- enantiocontrol. Conversely, the bulky tert-butyl-decorated (R)-spirophosphoramidite L5 imposed a confined cavity, steering selectivity toward Si–C(sp2)-bond activation and predominantly afforded the regioisomeric (S)-2-silacyclohexenylarenes 18. In 2025, Gong and co-workers reported a visible-light-mediated
Substituent effects in N-acetylated phenylazopyrazole photoswitches
Beilstein J. Org. Chem. 2025, 21, 830–838, doi:10.3762/bjoc.21.66
- reported to either bathochromically shift the UV–vis absorption spectrum or lead to a better separation of the n→π* bands of the two photoisomers and allow for visible-light-responsive switches [23][24][25][26]. In recent years, heteroaryl azobenzene derivatives have revealed superior properties to
Photocatalyzed elaboration of antibody-based bioconjugates
Beilstein J. Org. Chem. 2025, 21, 616–629, doi:10.3762/bjoc.21.49
- ) that can form covalent bonds when exposed to UV or visible light. These photoaffinity tags or crosslinkers are designed to bind to specific biomolecules, such as proteins, nucleic acids, or lipids, in a highly selective manner. The light irradiation triggers a chemical reaction, such as a bond
- the agency of low-energy visible light with specific functional groups on biomolecules. This allows precise control over the conjugation process, enabling targeted modifications without affecting non-reactive sites. Although previous reviews have discussed the more traditional synthetic methods
- emerged as a transformative approach in the modification of proteins, enabling researchers to achieve selective and efficient conjugation under mild conditions [37]. By utilizing visible light and transition-metal catalysts, this technique allows the generation of reactive intermediates that can
Unprecedented visible light-initiated topochemical [2 + 2] cycloaddition in a functionalized bimane dye
Beilstein J. Org. Chem. 2025, 21, 500–509, doi:10.3762/bjoc.21.37
- E. M. Kosower in 1978. In this study, we report the topochemical cycloaddition of diethyl 2,6-dichloro-1,7-dioxo-1H,7H-pyrazolo[1,2-a]pyrazole-3,5-dicarboxylate (Cl2B), initiated by visible light. Crystal structure analysis confirmed that the reactive double bonds are parallel and coplanar, in line
- with the Schmidt criteria for topochemical cycloaddition. Additionally, two other bimane derivatives with different substitution patterns were synthesized and investigated. Our findings suggest that functionalizing bimanes to redshift their absorption maxima into the visible-light spectrum provides a
- a [2 + 2] cycloaddition reaction, with approximately 20% yield of the dimer in the crystal. This was particularly notable, given that the compound had spent minimal time in solution with limited exposure to visible light, and no exposure to ultraviolet light. To further explore this phenomenon, we
Synthesis of N-acetyl diazocine derivatives via cross-coupling reaction
Beilstein J. Org. Chem. 2025, 21, 490–499, doi:10.3762/bjoc.21.36
- photoswitches with superior photophysical properties. The parent ethylene-bridged diazocine shows excellent switching photoconversion between the Z and the E configurations (Γ(Z → E)385nm = 92% and Γ(E → Z)520nm > 99% in n-hexane) due to well-separated n–π*-transitions in the visible part of the electromagnetic
Photomechanochemistry: harnessing mechanical forces to enhance photochemical reactions
Beilstein J. Org. Chem. 2025, 21, 458–472, doi:10.3762/bjoc.21.33
- rearrangements. Most organic molecules are colorless and, in fact, do not absorb visible light: highly energetic UV irradiation is typically needed. A milder approach is offered by photocatalytic approaches. Here, a photocatalyst is added to the reaction mixture to convert light energy into chemical potential to
- transform molecules. Intriguingly, photocatalysts typically absorb harmless visible light and can be chosen ad hoc to trigger the desired chemistry. Indeed, the photocatalyst–substrate interaction can occur via energy transfer [4][5][6][7][8], single-electron transfer [9][10][11][12], or hydrogen-atom
- interface two technologies, the authors opted to use mechanoluminescent powders to generate photons directly inside the jar. In more detail, SrAl2O4:Eu2+/Dy3+ (SAOED) was used as a mechanoluminescent material to drive the visible-light-mediated Hofmann–Loffler–Freytag (HLF) reaction (Scheme 12A). Thus, when
Antibiofilm and cytotoxic metabolites from the entomopathogenic fungus Samsoniella aurantia
Beilstein J. Org. Chem. 2025, 21, 327–339, doi:10.3762/bjoc.21.23
- ]+ (calculated 446.1962). The UV–vis spectrum of 1 (Figure S3, Supporting Information File 1) revealed a prominent absorption peak (λmax) at 434 nm in the visible region reflected by being yellow-colored and suggesting the presence of an extended conjugated π-system in its structure. The 1H NMR and 1H–1H COSY
Red light excitation: illuminating photocatalysis in a new spectrum
Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22
- own a large span of colors depending on the nature of the metal and the ligands but also on the various oxidation states these compounds can attain. This property results on the absorption of a visible-light photon complementary to the observed color and has been extensively exploited in photoredox
- efficiency of photoredox-catalyzed reactions. Absorption in the red region opens up innovative opportunities for photochemical transformations. First, the employed photon has the lowest energy in the electromagnetic spectrum of visible light, which allows for safer laboratory conditions in terms of
- properties of metal complexes. Phthalocyanins, porphyrins, and their derivatives exemplify this, as their rigid macrocyclic structures enable strong absorption in the visible to NIR regions, making them appealing for photoredox catalysis applications. For instance, ruthenium phthalocyanin complexes have
Effect of substitution position of aryl groups on the thermal back reactivity of aza-diarylethene photoswitches and prediction by density functional theory
Beilstein J. Org. Chem. 2025, 21, 242–252, doi:10.3762/bjoc.21.16
- the visible region for all molecules, in which a visible absorption maximum was observed at 487, 467, 447, 454, and 440 nm for N3(c), N4(c), and I1(c)–I3(c). Note that the λmax of I4(c) could not be determined due to the overlapping absorption bands of the open-ring and closed-ring isomers. The
- absorption band in the visible region disappeared and returned to the initial one by stopping UV light irradiation. These results indicate that all molecules exhibit T-type photochromic reactions based on 6π aza-electrocyclic reaction. The absorption bands of compounds I1(c)–I4(c) are blue-shifted compared
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