Methodology for awakening the potential secondary metabolic capacity in actinomycetes

• Shun Saito and
• Midori A. Arai

Beilstein J. Org. Chem. 2024, 20, 753–766, doi:10.3762/bjoc.20.69

• et al. applied a fluorescence-based DNA cleavage assay coupled with HiTES to Streptomyces clavuligerus and identified the steroid 11α-hydroxyprogesterone (14) as an effective elicitor and characterized 10 cryptic enediyne-derived natural products, designated clavulynes A (15) and B–J with unusual

Isolation and structure determination of a new analog of polycavernosides from marine Okeania sp. cyanobacterium

• Kairi Umeda,
• Naoaki Kurisawa,
• Ghulam Jeelani,
• Tomoyoshi Nozaki,
• Kiyotake Suenaga and
• Arihiro Iwasaki

Beilstein J. Org. Chem. 2024, 20, 645–652, doi:10.3762/bjoc.20.57

• in 100 mL phosphate-buffered saline) was added to each well. The plates were incubated for an additional 3 h. The plates were read in a SpectraMax Gemini XS microplate fluorescence scanner (Molecular Devices) using an excitation wavelength of 536 nm and an emission wavelength of 588 nm. WI-38 cells

Synthesis of photo- and ionochromic N-acylated 2-(aminomethylene)benzo[b]thiophene-3(2Н)-ones with a terminal phenanthroline group

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Irina V. Dubonosova,
• Olga Yu. Karlutova,
• Oleg P. Demidov,
• Alexander D. Dubonosov and
• Vladimir A. Bren

Beilstein J. Org. Chem. 2024, 20, 552–560, doi:10.3762/bjoc.20.47

• light and H+ or sequential addition of Fe2+ and AcO− ions. Keywords: fluorescence; molecular switches; N→O acyl rearrangement; naked eye effect; photochromism; Introduction Photochromism is defined as the reversible transformation of a molecular entity between different forms, having different

• -Acylated compounds 2a–c in solutions exhibited fluorescence in the region of 465–468 nm, and the excitation emission spectra agreed well with the absorption spectra (Figure 1). Compounds 2a–c in solutions demonstrated a typical negative photochromism [1][16] when irradiated with visible light of 436 nm

• (Figure 2). A decrease in the long-wavelength absorption was accompanied by a simultaneous increase in the shorter-wavelength absorption in the spectral region around 370 nm. During this process, a gradual diminishment of the initial fluorescence intensity at 465–468 nm up to zero was observed. The

Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors

• Jens Frackenpohl,
• David M. Barber,
• Guido Bojack,
• Birgit Bollenbach-Wahl,
• Ralf Braun,
• Rahel Getachew,
• Sabine Hohmann,
• Kwang-Yoon Ko,
• Karoline Kurowski,
• Bernd Laber,
• Rebecca L. Mattison,
• Thomas Müller,
• Anna M. Reingruber,
• Dirk Schmutzler and
• Andrea Svejda

Beilstein J. Org. Chem. 2024, 20, 540–551, doi:10.3762/bjoc.20.46

• binding affinity to enzyme targets, e.g., acyl-ACP thioesterases, belonging to the protein family of FATs, was demonstrated by using co-crystallization, fluorescence-based thermal shift assays, and chemoproteomics techniques [3]. Likewise, methiozolin (2) is a recently assigned FAT inhibitor that has

• . Active fractions were pooled together, and the buffer was exchanged into 25 mM potassium phosphate buffer pH 7.3 containing 10% glycerol with PD10 columns (GE Healthcare). Aliquots of the protein solution were frozen in liquid nitrogen and stored at −80 °C. LpFAT A fluorescence polarization assay

• : Fluorescence polarization (FP) competition assays were performed at room temperature in black 96-well microtiter plates (Greiner, Catalog No. 655900). The assay mixture contained 25 mM potassium phosphate buffer pH 7.3, 200 mM NaCl, 0.01% Triton X-100, 2 nM fluorescent tracer, 0.4 µg of purified LpFAT A

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• signals in the low-range visible/NIR region. Upon protonation of the pyridine, the conformation switch leads to a spatial separation of the active Pt moieties and a release of the guest (Figure 4). Also, the same group demonstrated the induction of chirality and fluorescence with chiral guest molecules

• using a similar principle [24]. The protection from the solvent of the intercalated Pt guest enables its fluorescence emission and is accompanied by the induction of chirality in the resulting host–guest complex. A significant enhancement of the circular dichroism response of the chiral guest is

• chiroptical properties with a large change in the absorption spectra and a bathochromic shift in the emission maximum. This system represents a rare example of a multi-output readout system, showing responses in ECD, fluorescence, and CPL activity. The authors later reported a similar system with a bipyridine

Development of a chemical scaffold for inhibiting nonribosomal peptide synthetases in live bacterial cells

• Fumihiro Ishikawa,
• Sho Konno,
• Hideaki Kakeya and
• Genzoh Tanabe

Beilstein J. Org. Chem. 2024, 20, 445–451, doi:10.3762/bjoc.20.39

• fluorescence scanning (excitation wavelength, 532 nm; emission wavelength, 580 nm). The labeling of GrsA by probe 3 was completely suppressed by the addition of inhibitors 1, 2, 4, 5, and 7 (Figure 4a). In contrast, inhibitors 6, 8, and 9 moderately inhibited labeling, which was consistent with the decreased

• 4–9 (100 µM), irradiated at 365 nm, and subjected to the click reaction with TAMRA-N3. In-gel fluorescence scanning revealed that inhibitors 1, 2, 4, and 7 completely suppressed GrsA labeling by probe 3 in the proteomic environment (Figure 4b). Unlike the results obtained for the labeling of

• are treated with a TAMRA-N3 under copper(I)-catalyzed azide–alkyne cycloaddition conditions, followed by SDS-PAGE coupled with in-gel fluorescence scanning. AMS, 5′-O-sulfamoyladenosine. Competitive labeling experiments of GrsA using probe 3 in the presence of ʟ-Phe-AMS inhibitors. (A) Labeling of

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• a reductive quenching mechanism. However, since the overall transformation is redox-neutral, no stoichiometric reductant was employed. Instead, fluorescence-quenching studies suggested that the reductive quenching of the iridium excited state (*IrIII) was taking place "off-cycle" via oxidation of

• photosensitizer in an energy-transfer (EnT) mechanism. This proposal was supported by fluorescence quenching measurements, as well as the direct excitation of 44 by UV irradiation, resulting in the formation of 45 in a 45% yield. According to this hypothesis, NHPI ester 44 would adopt a favorable conformation (46

Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines

• Eugeny Ivakhnenko,
• Vasily Malay,
• Pavel Knyazev,
• Nikita Merezhko,
• Nadezhda Makarova,
• Oleg Demidov,
• Gennady Borodkin,
• Andrey Starikov and
• Vladimir Minkin

Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34

• widened the scope and provided an access to derivatives of N,O- and N,S-heteropentacyclic quinoxalinophenoxazine, triphenodioxazine and oxazinophenothiazine systems. Keywords: 3H-phenoxazin-3-one; fluorescence; molecular structure; pentacyclic heterocycles; synthesis; Introduction 3H-Phenoxazin-3-one

• -phenoxazin-3-ones 4, compounds 5 and 6 display intense fluorescence in solution at room temperature (Figure 5). The excitation spectra of the compounds (Figures S7–S11, Supporting Information File 1) correspond to the longest-wavelength absorption bands. The absorption and emission spectra of benzo[5,6][1,4

• 6a,b) and c = 2⋅10−6 M (compound 10c) in toluene solutions with a Varian Cary Eclipse fluorescence spectrophotometer. UV–vis and fluorescence spectra were recorded using standard 1 cm quartz cells at room temperature. Toluene of spectroscopic grade (Aldrich) was used to prepare the solutions. The

Elucidating the glycan-binding specificity and structure of Cucumis melo agglutinin, a new R-type lectin

• Jon Lundstrøm,
• Emilie Gillon,
• Valérie Chazalet,
• Nicole Kerekes,
• Antonio Di Maio,
• Ten Feizi,
• Yan Liu,
• Annabelle Varrot and
• Daniel Bojar

Beilstein J. Org. Chem. 2024, 20, 306–320, doi:10.3762/bjoc.20.31

• fluorescence scanners, which can be paired with glycan information due to the known arrangements of immobilized glycans on the plate. To cover the broadest possible sequence space, we tested our eukaryotically produced CMA1 protein against the two largest glycan arrays at the National Center for Functional

• replicates of six. Results from replicates were combined as average RFU (raw fluorescence unit). For this average, the highest and lowest value was removed for each glycan, mitigating the effects of outliers. The results can be found in Supporting Information File 1, table “cfg”. ICL array For experiments, a

• raised by 1 °C/min from 25 to 100 °C, and fluorescence readings were taken at each step. Surface plasmon resonance spectroscopy Experiments were performed using a Biacore X100 instrument (Cytiva) at 25 °C in HBS-T running buffer (10 mM HEPES pH 7.4, 150 mM NaCl and 0.05% Tween 20). Biotinylated PAA

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• dithienonaphthalene products (e.g., 16) exhibit very different fluorescence properties, S-extrusion from thiophene-annelated thiepines was consequently exploited for peroxide sensing. Very recently, Zhou et al. reported the synthesis of S-doped phenanthrene and triphenylene derivatives via the thermally-induced ring

Substitution reactions in the acenaphthene analog of quino[7,8-h]quinoline and an unusual synthesis of the corresponding acenaphthylenes by tele-elimination

• Ekaterina V. Kolupaeva,
• Narek A. Dzhangiryan,
• Alexander F. Pozharskii,
• Oleg P. Demidov and
• Valery A. Ozeryanskii

Beilstein J. Org. Chem. 2024, 20, 243–253, doi:10.3762/bjoc.20.24

• difficult to purify compound 8. At the same time, isolation of the new product 8 turned out to be more convenient on using the simple KOH/EtOH system. These conditions did not affect the yield of acenaphthylene 8 (Scheme 9). Compound 8 possesses fluorescence in solutions and the solid state both as the base

Synthesis of the 3’-O-sulfated TF antigen with a TEG-N₃ linker for glycodendrimersomes preparation to study lectin binding

• Mark Reihill,
• Hanyue Ma,
• Dennis Bengtsson and
• Stefan Oscarson

Beilstein J. Org. Chem. 2024, 20, 173–180, doi:10.3762/bjoc.20.17

• silica gel 60 F254. Visualisation was performed with UV-light (254 nm) fluorescence quenching, and/or by staining with an 8% H2SO4 dip (stock solution: 8 mL conc. H2SO4, 92 mL EtOH), ninhydrin dip (stock solution: 0.3 g ninhydrin, 3 mL AcOH, 100 mL EtOH) and/or ceric ammonium molybdate dip (stock

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• column. In 62, unlike 59 and 60, thermally induced racemization was observed and kinetic parameters were obtained (ΔG‡298 K = 25.4 kcal mol−1), which were similar to those reported for 57 and 58 [133]. Photoluminescence properties Most anilino-substituted TCBD molecules exhibit negligible fluorescence in

• chloroform, while only a few exhibit weak fluorescence in hexane [15]. These nonluminescence characteristics are attributable to the low-energy state of the twisted ICT (TICT) state, which is capable of deactivating the ground state through accessible conical intersections (CIs) [15][134][135][136]. In

• -emission (AIE)-active aggregates exhibit emissive behavior in hexane, with an emission peak at 679 nm and a shoulder at 717 nm along with a fluorescence quantum yield of 8.5%. This luminescence phenomenon can be aptly considered to be AIE, considering the pronounced constraints imposed on molecular

Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions

• Julika Schlosser,
• Olga Fedorova,
• Yuri Fedorov and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11

• their DNA-binding properties with calf thymus (ct) DNA. The titrations of ct DNA to compounds 2d–g resulted in no or only negligible changes of the absorption and fluorescence spectra (cf. Supporting Information File 1, Figures S8–S11), indicating that these substrates do not interact significantly with

• efficient fluorescence quenching (Figure 5), which is commonly observed with this class of cationic ligands [3][70], mainly as a result of a photoinduced electron transfer from the excited, DNA-bound ligand with the DNA bases [71]. The binding isotherms obtained from the titration data were used to

• Varian Cary Eclipse fluorescence spectrometer with Hellma quartz glass cuvettes 115 FQS (layer thickness d = 10 mm). All measurements were recorded at T = 20 °C as adjusted with a thermostat, if not stated otherwise. The sample solutions in the DNA experiments were mixed with a reaction vessel shaker Top

Long oligodeoxynucleotides: chemical synthesis, isolation via catching-by-polymerization, verification via sequencing, and gene expression demonstration

• Yipeng Yin,
• Reed Arneson,
• Alexander Apostle,
• Adikari M. D. N. Eriyagama,
• Komal Chillar,
• Emma Burke,
• Martina Jahfetson,
• Yinan Yuan and
• Shiyue Fang

Beilstein J. Org. Chem. 2023, 19, 1957–1965, doi:10.3762/bjoc.19.146

• on an agar plate containing kanamycin and rhamnose. As shown in Figure 4, GFP was successfully expressed. As a negative control, a portion of the culture was also plated on an agar plate containing kanamycin but not rhamnose. As expected, fluorescence of GFP was not observed. The same gene expression

• of 55% predicted in the above analysis. To demonstrate protein synthesis using genes constructed from the long synthetic ODNs, the pF1K vector containing the 800 bp GFP gene construct derived from the CBP purified 399 and 401 nt ODNs was transformed into E. coli KRX cells. Green fluorescence was

• observed upon induction using rhamnose (Figure 4). Without rhamnose induction, no fluorescence was observed. The gene expression results were identical to those using the control 800 bp GFP gene from a commercial source. Therefore, the complete process from automated long ODN synthesis, ODN purification by

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

Beilstein J. Org. Chem. 2023, 19, 1895–1911, doi:10.3762/bjoc.19.141

• % yields, respectively. When comparing compounds 25a and 25b, UV–vis and fluorescence studies (λmax = 500 nm, λem = 502 nm, Φem = 0.45 for 25a; λmax = 513 nm, λem = 517 nm, Φem = 0.26 for 25b; λmax = 442 nm, λem = 444 nm, Φem = 0.97 for 9,10-bis((triisopropylsilyl)ethynyl)anthracene – blue-colored) provide

• yield of 81% over the two steps. To obtain the PAH 51, a second Pd-catalyzed annulation and subsequent aromatization of 50 were performed in an acidic medium. Ultimately, the desired compound, PAH 51 bearing TIPS groups, was obtained in 82% yield as the final product. UV–vis and fluorescence studies

• demonstrated significant absorption and fluorescence characteristics. Among the synthesized compounds, linear derivative 62 exhibited the most intense absorption peak (λmax = 503 nm), whereas the other two compounds 63 and 64 possessed slightly blue-shifted absorption maxima at 487 nm and 501 nm, respectively

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

• research on organic compounds exhibiting thermally activated delayed fluorescence (TADF) has led to numerous patents and research articles. This study focuses on the synthesis and investigation of the semiconducting properties of polyaromatic π-systems containing two and three fragments of pyridine-2,6

• electronic devices including OLEDs. Thus, extensive search for organic dyes exhibiting E-type fluorescence (thermally activated delayed fluorescence (TADF)) is booming [1][2][3]. The majority of research results are protected by an impressive amount of patent applications. The first example of a blue TADF

• bands and high-intensity low-energy bands. The presence of two distinct fluorescence bands is an indication of the existence of molecular conformations separated by a barrier. This is a characteristic of twisted internal charge transfer (TICT) states. It is worth of noting that the PL intensity of

Thienothiophene-based organic light-emitting diode: synthesis, photophysical properties and application

• Recep Isci and
• Turan Ozturk

Beilstein J. Org. Chem. 2023, 19, 1849–1857, doi:10.3762/bjoc.19.137

• absorption and emission maxima of 411 and 520 nm, respectively, with a mega Stokes shift of 109 nm and fluorescence quantum yields both in the solid state (41%) and in solution (86%). The optical properties were supported by computational chemistry using density functional theory for optimized geometry and

• emitter for an organic light-emitting diode through a solution process. DMB-TT-TPA (8) displayed excellent performance in both device application and photophysical properties, i.e., a maximum solution fluorescence quantum yield of 86% in THF, maximum solid-state fluorescence quantum yield of 41%, maximum

• lithiation of 7 and following reaction with dimesitylboron fluoride in 85% yield (Scheme 1). Photophysical properties The UV–vis absorption and fluorescence spectra of DMB-TT-TPA (8) were recorded in THF (Figure 1 and Table 1) [38]. It showed maximum absorption and emission wavelengths of 411 and 520 nm

Charge carrier transport in perylene-based and pyrene-based columnar liquid crystals

• Alessandro L. Alves,
• Simone V. Bernardino,
• Carlos H. Stadtlober,
• Edivandro Girotto,
• Giliandro Farias,
• Rodney M. do Nascimento,
• Sergio F. Curcio,
• Thiago Cazati,
• Marta E. R. Dotto,
• Juliana Eccher,
• Leonardo N. Furini,
• Hugo Gallardo,
• Harald Bock and
• Ivan H. Bechtold

Beilstein J. Org. Chem. 2023, 19, 1755–1765, doi:10.3762/bjoc.19.128

• listed in Table 2. The fitted fluorescence decay curves are shown in Supporting Information File 1 (Figure S1). For diluted solutions of 1 and 2, monoexponential lifetimes in the nanosecond timescale were observed and attributed to emission from monomeric species (6.54 and 4.14 ns, respectively). In the

• monomeric species [34]. It agrees with the intensity inversion of the vibronic absorption bands and PL redshift in the spin-coated film compared to the solution. The intensity inversion suggests formation of H-aggregates, leading to excimer fluorescence [35]. Due to the similarity to the lifetime in

• Optics USB4000 spectrophotometer. The PL spectra were collected with a Hitachi fluorescence spectrophotometer (Model F-7000) and the samples were excited at the wavelength of maximal absorption. For the PL as a function of the temperature, casting films were placed on a hot stage (Mettler Toledo FP-82

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

• devices is discussed in detail. Additionally, their significance as thermally activated delayed fluorescence emitters and chromophores for OLEDs, sensors and electrochromic devices is explored. The review emphasizes the remarkable characteristics and versatility of quinoxaline derivatives in electron

• high electron mobility and efficient charge transfer. In particular, Qx derivatives find use as non-fullerene acceptors (NFAs) in OSCs and as essential building blocks in sensitizers for DSSCs. The significance of Qx extends beyond to thermally activated delayed fluorescence (TADF) emitters and

• scientific community due to their remarkable characteristics as electron-transporting and hole-blocking layers in organic electronics [60]. Moreover, these derivatives have exhibited promising traits as thermally activated delayed fluorescence (TADF) emitters. This multifaceted nature has spurred ongoing

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

• designing new DR/NIR organic fluorophores in combination with device engineering to build up the performance of DR/NIR OLEDs. In general, to realize high fluorescence in the DR/NIR region from the organic fluorophores, the challenges of their pronounced non-radiative processes, and high planarity and

• energy gap between HOMO/LUMO hybrid orbits and drive fluorescence emission to longer wavelengths [48][49]. In this molecular design, the strong electron-deficient naphtho[2,3-c][1,2,5]thiadiazole (Nz) [13][50][51] as an acceptor and the strong electron-donating carbazole [52] as a donor unit were used 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

• the dipyrrin part of the macrocycle (Figure 4). The introduction of the BF2 moiety into the free-base macrocycles consequently altered the fluorescent properties of the macrocyclic systems. The appended benzo-18-crown-6 in compounds 3a–c was selective for K+, and the macrocycle fluorescence was

• alkylammonium guests. The binding constants Ka in CHCl3/MeOH 9:1 determined for 9-Zn complexes with [NH3(CH2)NH2]+, [NH3(CH2)2NH3]2+, [NH3(CH2)3NH3]2+, and [NH3CH2CH3]+ equal to 8.3·103, 6.2·103, 8.7·103, and 7.7·102 M−1, respectively, were reported. Based on the fluorescence quenching experiments the formation

• revealed a distorted ruffled molecule with a macrocycle incorporating a pyrroloindole subunit formed through the fusion between the para-phenylene ring and the pyrrolic nitrogen. 42 demonstrated fluorophore behaviour with relatively large fluorescence quantum yields of 10–20% and singlet state lifetimes of

Cyclodextrins permeabilize DPPC liposome membranes: a focus on cholesterol content, cyclodextrin type, and concentration

• Ghenwa Nasr,
• Hélène Greige-Gerges,
• Sophie Fourmentin,
• Abdelhamid Elaissari and
• Nathalie Khreich

Beilstein J. Org. Chem. 2023, 19, 1570–1579, doi:10.3762/bjoc.19.115

• individually treated with 0.15 mM, 1.5 mM, and 15 mM of CDs (CD/DPPC molar ratios 1:1, 10:1 and 100:1, respectively). Following the exposure of liposomes to CDs, the samples were incubated at 37 °C and the fluorescence signals were measured at time 0, 4, and 24 h. For each formulation, the effect of CDs was

• of CD treated liposomes is equal to 0.15 mM, 1.5 mM, and 15 mM in respect to the CD/DPPC molar ratios: 1:1, 10:1, and 100:1, respectively. The fluorescence signal was measured for each sample immediately after the exposure of LUVs to CDs and the samples were incubated at 37 °C during 24 h. For each

• formulation, a solution containing only liposomes was used as the blank solution. The membrane permeability study by fluorescence spectroscopy The membrane permeability is commonly evaluated by following the leakage of self-quenching probes such as SRB from liposomes [14]. Indeed, a fluorescence auto

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

• Abstract Organic thermally activated delayed fluorescence (TADF) materials have been widely investigated due to their impressive electronic properties and applied potential for the third generation of organic light-emitting diodes (OLED). We present organic TADF material (4BGIPN) based on the strained

• : guanidine; organic; photoluminescence; TADF; yellow; Introduction Thermally activated delayed fluorescence (TADF) is a photoluminescence mechanism where excitons undergo thermally-assisted reverse-intersystem crossing from an excited triplet state to a higher-lying in energy singlet state to emit delayed

• fluorescence [1][2][3]. Organic TADF emitters have gained substantial attention in recent years for their prospective application in organic light-emitting diodes (OLEDs), photocatalysis, bioimaging, and sensors [4][5][6]. The ability to harvest both singlet and triplet excitons enable organic TADF emitters to

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

• ; Zn-TMPP, Soret band at 425 nm) due to the extended π-conjugation after the fusion of the benzo[f]chromeno[2,3-h]quinoxaline moiety at the β-pyrrolic positions of the porphyrin macrocycle. In the fluorescence spectra, free-base benzo[f]chromeno[2,3-h]quinoxalinoporphyrins 9–13 showed emission bands at

• ≈675 nm and 730 nm (Figure 5a). These newly synthesized free-base porphyrins displayed significant red-shifts in their emission spectra in comparison to meso-tetrakis(4-methylphenyl)porphyrin (TMPP; emission bands at ≈652 and 717 nm). Similarly, fluorescence spectra of zinc(II) benzo[f]chromeno[2,3-h