Naphthalene diimide–amino acid conjugates as novel fluorimetric and CD probes for differentiation between ds-DNA and ds-RNA

• Annike Weißenstein,
• Myroslav O. Vysotsky,
• Ivo Piantanida and
• Frank Würthner

Beilstein J. Org. Chem. 2020, 16, 2032–2045, doi:10.3762/bjoc.16.170

• the type of polynucleotide, thus the studied NDI dyes act as dual fluorimetric/ICD probes for sensing the difference between here used GC-DNA, AT-DNA and AU-RNA. Keywords: amino acid–fluorophore conjugate; circular dichroism; DNA/RNA recognition; fluorescence; intercalation; naphthalene diimide

• colourless and non-fluorescent core-unsubstituted NDI with a new charge transfer band with an absorption maximum in the visible spectral range and a high fluorescence quantum yield (up to 58%) [23][25]. Further, the 2-amino substituent offers the possibility to connect various amino acid side chains, thus

• stability of similar NDI compounds is greater in weakly acidic buffer solution over a longer period of time [24]. Compounds 3a,b, and 5 revealed absorption maxima of 518–540 nm with molar extinction coefficients of nearly 10000 M−1 cm−1 (Figure 2). Further, 3a,b, and 5 show strong fluorescence at 573–602 nm

pH- and concentration-dependent supramolecular self-assembly of a naturally occurring octapeptide

• Goutam Ghosh and
• Gustavo Fernández

Beilstein J. Org. Chem. 2020, 16, 2017–2025, doi:10.3762/bjoc.16.168

• fractal-like morphologies, as verified by circular dichroism (CD), Fourier-transform infrared (FTIR) spectroscopy, thioflavin T (ThT) fluorescence spectroscopy assay, and atomic force microscopy (AFM). Upon changing the pH value (using pH 5.5 and 13.0), PEP-1 forms different types of secondary structures

• fluorescence spectroscopy assay were used to investigate the formation of secondary structures from PEP-1 during the self-assembly. The CD spectrum of PEP-1 at pH 7.4 (PBS buffer, c = 5.0 × 10−4 M) showed an intense negative band at around 226 nm that indicated the characteristic signature of a β-sheet-rich

• ]. The band at 1678 cm−1 was the characteristic feature of an antiparallel conformation of the sheet structure or the β-turn structure [61]. To further confirm the β-sheet formation, we performed a ThT fluorescence spectroscopy assay. ThT is a widely used fluorescent dye that is amyloid-specific and can

Automated high-content imaging for cellular uptake, from the Schmuck cation to the latest cyclic oligochalcogenides

• Rémi Martinent,
• Javier López-Andarias,
• Dimitri Moreau,
• Yangyang Cheng,
• Naomi Sakai and
• Stefan Matile

Beilstein J. Org. Chem. 2020, 16, 2007–2016, doi:10.3762/bjoc.16.167

• high-content (HC) microscopy can satisfy this need. The automated imaging of thousands of cells per condition in multiwell plates allows us to obtain quantitative data on not only the fluorescence intensity but also on the localization in a very short time. Quantitative and statistically relevant

• aqueous solvents was evaluated by a series of experimental studies, such as NMR, UV, CD, and fluorescence titrations [23][25]. The Schmuck cation indeed showed a much higher affinity towards carboxylates, with dissociation constants of KD ≈ 1 mM (4: 620 µM; 5: 1.3 mM) compared to simple acylguanidinium

• ][58] has been suggested to further improve the standards set by the CAPA [59]. Standard high-throughput (HT) screening has been used regularly to facilitate studies on cellular uptake [60]. In standard assays, a single macroscopic parameter, usually the fluorescence intensity, is automatically

Et₃N/DMSO-supported one-pot synthesis of highly fluorescent β-carboline-linked benzothiophenones via sulfur insertion and estimation of the photophysical properties

• Dharmender Singh,
• Vipin Kumar and
• Virender Singh

Beilstein J. Org. Chem. 2020, 16, 1740–1753, doi:10.3762/bjoc.16.146

• , β-carbolines are also used as fluorescence standards. Recently, a novel β-carboline-based fluorescent chemosensor was developed by Batra and co-workers for the quantitative analysis of fluoride ions (F−) at ppb level [19]. Sulfur-containing organic compounds are broadly associated with numerous

• accelerate the transformation. Photophysical studies Fluorescence, offering a nondestructive exceptional technique to monitor a system of interest at the molecular level [70][71][72], has found wide-ranging applications in several research areas such as medicine, pharmaceutics, biology, environment, and food

• chemosensors, ligands, and fluorescent probes. In order to investigate the fluorescence properties, compound 2bA was chosen as the model substrate for optimization of various parameters like time, concentration, and solvent. In order to obtain the maximum emission, various solvents were screened. The

Nonenzymatic synthesis of anomerically pure, mannosyl-based molecular probes for scramblase identification studies

• Giovanni Picca,
• Markus Probst,
• Simon M. Langenegger,
• Oleg Khorev,
• Peter Bütikofer,
• Anant K. Menon and
• Robert Häner

Beilstein J. Org. Chem. 2020, 16, 1732–1739, doi:10.3762/bjoc.16.145

• glycosylation is described. Two short-chain glycolipid analogs that mimic the naturally occurring substrate mannosyl phosphoryl dolichol exhibit either photoreactive and clickable properties or allow the use of a fluorescence readout. Both probes consist of a hydrophilic mannose headgroup that is linked to a

• structure in which the citronellyl–dodecanyl linker is located in the phospholipid membrane, and the mannose and the NBD are positioned in the surrounding aqueous medium. The close proximity of the NBD fluorophore to the membrane–water interface [30][31] allows for fluorescence-based scramblase assays

Clickable azide-functionalized bromoarylaldehydes – synthesis and photophysical characterization

• Dominik Göbel,
• Marius Friedrich,
• Enno Lork and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2020, 16, 1683–1692, doi:10.3762/bjoc.16.139

• emission behavior. Keywords: bromoarylaldehydes; click-chemistry; fluorenes; fluorescence; phosphorescence; Introduction Small organic luminophores exhibiting room-temperature phosphorescence (RTP) have attracted great attention due to promising applications in optoelectronic devices [1][2][3][4][5][6][7

• can occur. While the latter decay (fluorescence) takes place without a change in the electron spin, phosphorescence is defined as the radiative transition from the lowest excited triplet state (T1) to the singlet ground state (S0) [18][19][20][21]. Triplet state excitons are generated by the spin

• ISC processes through intermolecular halogen bonding to generate efficient RTP was initially investigated by Kim et al. [58]. They developed the minimalistic 2,5-dihexyloxy-4-bromobenzaldehyde (1) [59][60][61][62][63] which showed a weak fluorescence in solution, but exhibited a green phosphorescence

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

Synthesis of new fluorescent molecules having an aggregation-induced emission property derived from 4-fluoroisoxazoles

• Kazuyuki Sato,
• Akira Kawasaki,
• Yukiko Karuo,
• Atsushi Tarui,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2020, 16, 1411–1417, doi:10.3762/bjoc.16.117

• synthesized and investigated for their photochemical properties. The introduction of a fluorine substituent into 3,5-diarylisoxazoles led to an increase of fluorescence intensity and exhibited a redshift in the emission intensity. α-Fluorinated boron ketoiminates (F-BKIs) were also synthesized via a ring

• ; Introduction Fluorescence bioprobes based on conventional organic dyes are used for enzyme activity measurements and in bioimaging systems with promising applications in the field of clinical diagnostics [1][2][3][4][5][6][7]. Most of the fluorescence bioprobes are mainly excited with near-ultraviolet or blue

• light ray and the structures often include fluorescein, rhodamine, or 7-amino-4-methylcoumarin (7-AMC) scaffolds as fluorophores. These fluorophores usually exhibit strong fluorescence in dilute solutions, but most of their emissions are partially or completely quenched in the solid state or in highly

Anthelmintic drug discovery: target identification, screening methods and the role of open science

• Frederick A. Partridge,
• Ruth Forman,
• Carole J. R. Bataille,
• Graham M. Wynne,
• Marina Nick,
• Angela J. Russell,
• Kathryn J. Else and
• David B. Sattelle

Beilstein J. Org. Chem. 2020, 16, 1203–1224, doi:10.3762/bjoc.16.105

• researchers, The Worm Breeder’s Gazette, which combines advice and suggestions on methods with informal communication of new findings in advance of publication. For example, the Nobel prize-winning use of a green fluorescence protein as a marker was reported in the Gazette by Martin Chalfie and colleagues

• of C. elegans viability and fluorescence [141]. Open tools for more detailed analysis of helminth physiology Sophisticated software and hardware methods have been developed to phenotype more subtle aspects of worm biology than paralysis/motility/viability assays. These methods could form a fruitful

Development of fluorinated benzils and bisbenzils as room-temperature phosphorescent molecules

• Shigeyuki Yamada,
• Takuya Higashida,
• Yizhou Wang,
• Masato Morita,
• Takuya Hosokai,
• Kaveendra Maduwantha,
• Kaveenga Rasika Koswattage and
• Tsutomu Konno

Beilstein J. Org. Chem. 2020, 16, 1154–1162, doi:10.3762/bjoc.16.102

• photophysical properties of the benzil and bisbenzil derivatives in toluene at 25 °C showed both fluorescence with a photoluminescence (PL) band at a maximum wavelength (λPL) of around 400 nm and phosphorescence with a PL band at a λPL of around 560 nm. Interestingly, intersystem crossing effectively caused

• materials. Keywords: alkyne oxidation; benzils; bistolanes; fluorinated compounds; phosphorescence; Introduction The development of organic light-emitting molecules is recognized as one of the most important studies because of the broad application of these compounds as fluorescence probes, bio-imaging

• materials, and biosensors in biomedical diagnostics [1][2][3][4] and as organic light-emitting diodes in the technological field [5][6][7][8]. Among the organic light-emitting molecules developed thus far, extended π-conjugated compounds (e.g., pyrenes and perylenes) emit fluorescence, which is a radiative

Synthesis and properties of quinazoline-based versatile exciplex-forming compounds

• Rasa Keruckiene,
• Simona Vekteryte,
• Ervinas Urbonas,
• Matas Guzauskas,
• Eigirdas Skuodis,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101

• ; quinazoline; Introduction Organic luminescent materials are extensively used in a wide range of optoelectronic devices. For the design of compounds, potentially exhibiting properties such as bipolar charge transport, delayed fluorescence or aggregation-induced emission enhancement (AIEE), a useful strategy

• properties [8]. A quinazoline-based emitter exhibiting thermally activated delayed fluorescence (TADF) was also reported [6] and green to yellow TADF OLEDs were fabricated with EQEs from 17.6 to 20.5%. The multicolor emission of a quinazoline–carbazole compound was employed in white OLEDs. White

• solutions of derivatives 1 and 2 displayed broad Gaussian forms, whereas the emission spectrum of compound 3 was narrow and slightly vibrational (Figure 5). The strongly red-shifted fluorescence bands (ca. 107 nm for 1 and 156 nm for 2) with respect to the LEB of absorption, were attributed to charge

A smart deoxyribozyme-based fluorescent sensor for in vitro detection of androgen receptor mRNA

• Ekaterina A. Bryushkova,
• Erik R. Gandalipov and
• Julia V. Nuzhina

Beilstein J. Org. Chem. 2020, 16, 1135–1141, doi:10.3762/bjoc.16.100

• enclosed inside a hybridized MGA, malachite green dye produces a signal (648 nm) after excitation on 610 nm, which is easily detectable by a fluorescence spectrophotometer. The complete SDFS was assembled by annealing the individual component strands (T1–T5) to each other. The efficiency of the SDFS

• mRNA by Dz1 and Dz2, which are parts of T1 and T4 strands, respectively, that leads to the release of a short 27-nt fragment from 60-AR_RNA (Figure 1F and G) near the MGA. Due to this a significant increase in fluorescence signal at the presence of malachite green was expected owing to the fact that 27

• -AR_RNA at 37 °C already in 6 hours. To estimate the functional activity of the SDFS we simultaneously evaluated the biosensor fluorescence intensity and the efficiency of the target RNA cleavage in the presence of SDFS under the same conditions. The complete assembled SDFS (100 nM), mix of Т1–Т5 (100 nM

Synthesis of esters of diaminotruxillic bis-amino acids by Pd-mediated photocycloaddition of analogs of the Kaede protein chromophore

• Esteban P. Urriolabeitia,
• Pablo Sánchez,
• Alexandra Pop,
• Cristian Silvestru,
• Eduardo Laga,
• Ana I. Jiménez and
• Carlos Cativiela

Beilstein J. Org. Chem. 2020, 16, 1111–1123, doi:10.3762/bjoc.16.98

• chromatography (TLC) was performed on Macherey-Nagel Polygram® SIL G/UV254 silica gel on polyester sheets, with manganese-activated zinc silicate with green fluorescence for short-wave UV (254 nm) and special inorganic fluorescent pigment with blue fluorescence for long-wave UV (366 nm) as indicators. Fluka

Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

• Nuray Altinolcek,
• Ahmet Battal,
• Mustafa Tavasli,
• William J. Peveler,
• Holly A. Yu and
• Peter J. Skabara

Beilstein J. Org. Chem. 2020, 16, 1066–1074, doi:10.3762/bjoc.16.93

• , respectively. Keywords: carbazole; electrochemistry; fluorescence; formyl group; solvatochromism; Introduction Carbazole derivatives have found many different applications in a variety of technologically important areas, such as organic light emitting diodes (OLEDs), organic photovoltaics (OPVs), dye

• Fluorescence and Absorbance Spectrometer. Each compound (7a/7b) displayed three distinctive absorption bands in the UV–vis spectra: high energy bands and mid energy bands were assigned to π–π* and n–π* transitions, whereas the low energy bands were assigned to an intramolecular charge transfer (ICT) transition

• the meta position to the carbazole ring. The photoluminescence (PL) properties of compounds 7a and 7b were investigated in dichloromethane using a Duetta Fluorescence and Absorbance Spectrometer. Compounds 7a and 7b gave emission maxima at 561 nm and 482 nm, respectively. The UV–vis and PL spectra of

Aryl-substituted acridanes as hosts for TADF-based OLEDs

• Naveen Masimukku,
• Dalius Gudeika,
• Oleksandr Bezvikonnyi,
• Ihor Syvorotka,
• Rasa Keruckiene,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 989–1000, doi:10.3762/bjoc.16.88

• ”, 202 Stryska Str. 79031, Lviv, Ukraine 10.3762/bjoc.16.88 Abstract Four aryl-substituted acridan derivatives were designed, synthesized and characterized as electroactive materials for organic light emitting diodes based on emitters exhibiting thermally activated delayed fluorescence. These compounds

• demonstrated maximum external quantum efficiencies up to 3.2%. Keywords: acridan; hole mobility; host; OLED; thermally activated delayed fluorescence; Introduction Organic light emitting diodes (OLEDs) are perfect candidates for multicolor displays and for next generation energy saving large area-lighting

• devices [1]. Nowadays, organic compounds exhibiting thermally activated delayed fluorescence (TADF) are widely used as emitters for OLEDs [2]. The great interest in TADF emitters is mainly explained by their heavy-atoms-free molecular structure and 100% theoretical limit of internal quantum efficiency

Cation-induced ring-opening and oxidation reaction of photoreluctant spirooxazine–quinolizinium conjugates

• Phil M. Pithan,
• Sören Steup and
• Heiko Ihmels

Beilstein J. Org. Chem. 2020, 16, 904–916, doi:10.3762/bjoc.16.82

• fluorescence at ca. 1 h after the addition. All the other tested metal ions (see above) did not cause a change of the absorption and emission. The coralyne–spirooxazine conjugate 3b was weakly fluorescent upon the excitation at λex = 400 nm, with a broad emission band at λfl = 481 nm (Φfl = 0.007 relative to

• 500 V and 600 V, depending on the fluorescence intensity. The emission spectra were smoothed with the implemented moving-average function by a factor of 5. Emission spectra in the range between 600 nm and 850 nm were corrected with an instrument-specific correction curve. The fluorescence quantum

• . Absorption (A) and fluorescence spectrum (B) of 3a in MeCN (c = 5 µM) in the absence (black) and in the presence of metal ions ca. 1 h after the addition. Red: Cu2+ (c = 15 µM), orange: Hg2+ (c = 100 µM), blue: Li+, Na+, K+, Mg2+, Ca2+, Mn2+, Fe2+, Co2+, Ni2+, Zn2+, Ag+, and Pb2+ (c = 100 µM each); λex = 470

Bipyrrole boomerangs via Pd-mediated tandem cyclization–oxygenation. Controlling reaction selectivity and electronic properties

• Liliia Moshniaha,
• Marika Żyła-Karwowska,
• Joanna Cybińska,
• Piotr J. Chmielewski,
• Ludovic Favereau and
• Marcin Stępień

Beilstein J. Org. Chem. 2020, 16, 895–903, doi:10.3762/bjoc.16.81

• using NMR spectroscopy and DFT calculations [33]. In particular, the unprecedented double α-oxygenation of bipyrroles was shown to occur through stepwise acetoxylation, which we found to compete with α–α oligomerization. These new bipyrrole boomerangs exhibited enhanced fluorescence with Φfl values of

• bipyrroles are very efficient fluorophores (Table 2), noticeably more emissive than the lactam analogues and the other previously reported boomerangs [32]. Highest fluorescence quantum yields were observed in toluene (83 and 80%, respectively). For comparison, the Φfl values for the lactams cNMI2O and cNMI3O

• are about 1%. Interestingly, the fluorescence of cNMInH boomerang bipyrroles showed a stronger solvatochromic dependence than observed in their absorption spectra (Figure 2). In the more polar solvents, the emission profiles became significantly red shifted and broadened. At the same time, the

Aldehydes as powerful initiators for photochemical transformations

• Maria A. Theodoropoulou,
• Nikolaos F. Nikitas and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76

• of an α-hydroxybenzyl radical (11) and a benzoyl radical (10). This upper statement shows the potential of benzaldehyde (8) compared to the related aryl ketones, which are known to be capable of HAT. Until recently, the quenching of the fluorescence of excited benzaldehyde (9) was unreasonably

• thought to originate from the basicity of the aldehyde. A recent publication though came to empower the statement that the HAT properties of benzaldehyde (8) are responsible for the observed quenching of the fluorescence [34]. Aldehydes as photoinitiators for photochemical polymerizations A number of

• fluorescence quenching studies, UV–vis spectroscopy experiments, calculation of the quantum yield, a cutoff experiment below 400 nm, GC–MS analysis, and NMR spectroscopic mechanistic experiments. They also concluded that an energy transfer mechanism could not be possible since the solvent employed affected the

One-pot synthesis of dicyclopenta-fused peropyrene via a fourfold alkyne annulation

• Ji Ma,
• Yubin Fu,
• Junzhi Liu and
• Xinliang Feng

Beilstein J. Org. Chem. 2020, 16, 791–797, doi:10.3762/bjoc.16.72

• pentagons could be realized [11][12][13][14][15][16][17]. Among them, the cyclopenta-fused pyrenes are an important class of CP-PAHs owing to their unique physical and photophysical properties, such as high electron affinities and anomalous fluorescence [17][18][19][20]. However, the reported synthetic

• 1.78 eV from the onset of its UV–vis absorption spectrum. Similar to the cyclopenta-fused pyrene derivatives [28][29], compound 1 does not show detectable fluorescence emission. Furthermore, the electrochemical properties of 1 was probed by cyclic voltammetry (CV) in DCM (Figure 3b). According to the

Towards triptycene functionalization and triptycene-linked porphyrin arrays

• Gemma M. Locke,
• Keith J. Flanagan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2020, 16, 763–777, doi:10.3762/bjoc.16.70

• evident linearity in these systems. Moreover, initial UV–vis and fluorescence studies show the promise of triptycene as a linker for electron transfer studies, showcasing its isolating nature. Keywords: BODIPY; Pd-catalyzed cross-coupling; porphyrins; Sonogashira cross-coupling; triptycene; Introduction

• dimers and 8 nm (1.25 × 106 cm−1) for the monomer. The difference in properties of the unsymmetric zinc-nickel dimer 16 is observed significantly more in the corresponding fluorescence emission spectrum (Figure 7). The emission observed for the zinc monomer and dimer, 14 and 9, respectively, was

• significantly more enhanced, in comparison to the practically quenched fluorescence detected for the zinc-nickel dimer 16 which may be due to the electron-deficient nature of the nickel porphyrin [47]. In this instance, the excited zinc porphyrin is acting as electron donor while the electronically inactive

Synthesis of C₇₀-fragment buckybowls bearing alkoxy substituents

• Yumi Yakiyama,
• Shota Hishikawa and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2020, 16, 681–690, doi:10.3762/bjoc.16.66

• microwave experiment was carried out with a Biotage Initiator Eight EXP. UV–vis absorption spectra were recorded on a JASCO V-670 spectrometer and a SHIMADZU UV-1800 spectrometer. Fluorescence spectra were recorded on a JASCO FP-6500 spectrometer. Melting points were determined on a Stanford Research

Direct borylation of terrylene and quaterrylene

• Haruka Kano,
• Keiji Uehara,
• Kyohei Matsuo,
• Hironobu Hayashi,
• Hiroko Yamada and
• Naoki Aratani

Beilstein J. Org. Chem. 2020, 16, 621–627, doi:10.3762/bjoc.16.58

• fluorescence at 576 nm with a quantum yield of ΦF = 0.86 at 298 K (Figure 3). Both peaks are slightly red-shifted relative to those of intact terrylene (λabs = 560 nm and λem = 571 nm with ΦF = 0.82 in toluene). We employed density functional theory (DFT) and time-dependent (TD)-DFT calculations, both of them

• ], a slightly red-shifted absorption peak at 668 nm is observed. Interestingly, QB4 emits only weak fluorescence as was described for tetra-tert-butylquaterrylene [20]. The coefficient distribution of four frontier MOs of quaterrylenes basically exhibits the same symmetric pattern with terrylenes

• spectrophotometer V-570, and fluorescence spectra were measured with a JASCO PL spectrofluorometer FP-6600. Fluorescence quantum yields were measured on a HAMAMATSU Absolute PL Quantum Yield Measurement System C9920-02G. TLC and gravity column chromatography were performed on Art. 5554 (Merck KGaA) plates and

Regioselectively α- and β-alkynylated BODIPY dyes via gold(I)-catalyzed direct C–H functionalization and their photophysical properties

• Takahide Shimada,
• Shigeki Mori,
• Masatoshi Ishida and
• Hiroyuki Furuta

Beilstein J. Org. Chem. 2020, 16, 587–595, doi:10.3762/bjoc.16.53

• . Depending on the position of the ethynyl substituent in the BODIPY skeleton, the photophysical properties of the resulting α- and β-substituted BODIPYs are notably altered. The lowest S0–S1 transition absorbance and fluorescence bands are both bathochromically shifted as the number of substituents increases

• optical features such as intense and narrow S0–S1 absorption and emission bands in the visible-to-near-infrared region, a high fluorescence quantum yield, and good photostability. For the applications mentioned above, various BODIPY dyes functionalized at the meso-, α-, and β-pyrrolic positions have been

• comparative NMR analysis and mass spectrometry (see Supporting Information File 1). Optical properties The α- and β-ethynyl-substituted BODIPYs exhibit large bathochromic shifts in the absorption and fluorescence spectra relative to the unsubstituted 1a with extended π-conjugation (Figure 4 and Figure 5). The

Copper-catalyzed remote C–H arylation of polycyclic aromatic hydrocarbons (PAHs)

• Anping Luo,
• Min Zhang,
• Zhangyi Fu,
• Jingbo Lan,
• Di Wu and
• Jingsong You

Beilstein J. Org. Chem. 2020, 16, 530–536, doi:10.3762/bjoc.16.49

• fluorescence, and have been widely applied in many scientific areas including chemistry, biomedicine and materials science [1][2][3][4][5][6]. The arylation reaction of PAHs is an important strategy to further extend the π-conjugation length, which can effectively adjust the photophysical properties of

• , which corresponds to π−π* electron transition (Figure 1a and Table S2, Supporting Information File 1). The measurement of emission spectra demonstrates that 4k and 4n emit violet fluorescence with emission maxima at 395 nm and 390 nm, respectively, while 4o exhibits a sky-blue emission with an emission

Synthesis of triphenylene-fused phosphole oxides via C–H functionalizations

• Md. Shafiqur Rahman and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2020, 16, 524–529, doi:10.3762/bjoc.16.48

• nature as hybrids of triphenylene and benzo[b]phosphole. Keywords: C–H functionalization; fluorescence; phosphole; polycyclic aromatic hydrocarbons; triphenylene; Introduction The phosphorus-containing five-membered ring, phosphole, has attracted significant attention as a structural motif in π

• -containing ladder molecules and their application as fluorescence probes for biological imaging [10][11]. Marinetti extensively studied the synthesis of phosphahelicenes with linear fusion of the phosphole and the carbohelicene units [12], and their applications in asymmetric catalysis [13] and organic light

• , entry 3). Like many 2,3-dialkylbenzo[b]phospholes [17][35], 8a–c showed strong fluorescence in solution (ΦF = 0.67 and 0.34 for 8a and 8b, respectively). In contrast to the highly resolved bands in the absorption spectra, the fluorescence spectra were rather simple, with distinct emission peaks at 452