Synthesis, liquid crystalline behaviour and structure–property relationships of 1,3-bis(5-substituted-1,3,4-oxadiazol-2-yl)benzenes

• Afef Mabrouki,
• Malek Fouzai,
• Armand Soldera,
• Abdelkader Kriaa and
• Ahmed Hedhli

Beilstein J. Org. Chem. 2020, 16, 149–158, doi:10.3762/bjoc.16.17

• perfluoroalkyl as terminal chains were synthesized and characterized. Liquid crystal properties of the synthesized compounds have been investigated by polarizing optical microscopy, differential scanning calorimetry and X-ray diffraction techniques. Conformation effects of the synthesized products on the dipole

• compounds 2 and 4 is constituted by a rigid core (three aromatic rings) to which are attached the terminal chains. Based on this structure, some liquid crystalline mesophases were expected. Differential scanning calorimetry (DSC), polarized optical microscopy (POM) and X-ray diffraction pattern analysis

• intermediate phase between 118.0 °C and 138.4 °C in heating and between 96.5 °C and 121.1 °C in cooling, indicating a remarkable stabilization in a temperature range of 20 °C. Polarized optical microscopy (POM) In order to achieve a further illustration of the liquid crystal behavior, POM observations were

Potent hemithioindigo-based antimitotics photocontrol the microtubule cytoskeleton in cellulo

• Alexander Sailer,
• Franziska Ermer,
• Yvonne Kraus,
• Rebekkah Bingham,
• Ferdinand H. Lutter,
• Julia Ahlfeld and
• Oliver Thorn-Seshold

Beilstein J. Org. Chem. 2020, 16, 125–134, doi:10.3762/bjoc.16.14

• network within cells treated with HITubs and documented the resulting disruption of the physiological MT network integrity, and consequently also changes in cell morphology by confocal microscopy. Cells exposed to HITub-4 (1 μM) in the dark or under λ = 530 nm illumination (to maintain exclusively Z

• antiproliferative potencies at λ = 450 and 530 nm/dark conditions (75 ms pulsing every 15 s). b) EC50 values of HITubs from cellular antiproliferation assays under dark conditions and at λ = 450 nm. The ratio of lit/dark EC50 values shows the fold change in photoswitchable bioactivity. Confocal microscopy images of

Influence of the cis/trans configuration on the supramolecular aggregation of aryltriazoles

• Sara Tejera,
• Giada Caniglia,
• Rosa L. Dorta,
• Andrea Favero,
• Javier González-Platas and
• Jesús T. Vázquez

Beilstein J. Org. Chem. 2019, 15, 2881–2888, doi:10.3762/bjoc.15.282

• and distilled before use. ECD was recorded in the range of 200–400 nm at room temperature by using 10 mm quartz cells. SEM images were taken by a TEM, JEOL JEM 1010 belonging to the Electronic Microscopy Service (SEGAI) of the University of La Laguna, Spain. Compounds 7f, 8f, 9, 10, 11, and 12 were

Chemical tuning of photoswitchable azobenzenes: a photopharmacological case study using nicotinic transmission

• Lorenzo Sansalone,
• Jun Zhao,
• Matthew T. Richers and
• Graham C. R. Ellis-Davies

Beilstein J. Org. Chem. 2019, 15, 2812–2821, doi:10.3762/bjoc.15.274

• transfected with either wild-type (WT) α4β2 or mutant (E61C) nicotinic acetylcholine receptors [16]. Cells with successful ion channel expression co-expressed YFP visualized using epi-fluorescence microscopy. Cover slips were treated with all trans-1 (0.05 mM in physiological buffer) for 20 min in the dark

A photochemical determination of luminescence efficiency of upconverting nanoparticles

• Baptiste Amouroux,
• Clément Roux,
• Jean-Claude Micheau,
• Fabienne Gauffre and
• Christophe Coudret

Beilstein J. Org. Chem. 2019, 15, 2671–2677, doi:10.3762/bjoc.15.260

• good agreement with measurements obtained on bulk samples by using integrating spheres [33], and the order of magnitude of the emissive power of a single NP is close to what was achieved by microscopy on nanoparticles of similar composition but at a higher laser power (49 × 10−16 W under 976 nm

Plasma membrane imaging with a fluorescent benzothiadiazole derivative

• Pedro H. P. R. Carvalho,
• Jose R. Correa,
• Karen L. R. Paiva,
• Daniel F. S. Machado,
• Jackson D. Scholten and
• Brenno A. D. Neto

Beilstein J. Org. Chem. 2019, 15, 2644–2654, doi:10.3762/bjoc.15.257

• (pH 7.4) at room temperature and the coverslips were mounted over glass slides using ProLong Gold Antifade (Invitrogen, OR, USA) according to the manufacturer’s recommendations. These two main samples (of live and fixed cells) were analyzed using confocal microscopy and excited using 405 nm wavelength

• . Afterwards, the cells were washed three times in PBS and the samples were mounted over glass slides by using antifade agent Prolong Gold (Invitrogen, OR, USA) according to the manufacture’s recommendations. The samples were analyzed using confocal microscopy. CellMask was excited at 633 nm wavelength and the

• incubated with BTD-4APTEG (1 μM) in live (A) and (B) and fixed cells (C) and (D). (A) and (C) show the staining distribution of the new dye BTD-4APTEG in the plasma membrane of the cells. (B) and (D) show the normal morphological aspects of the samples by phase contrast microscopy. The dye was found

A new approach to silicon rhodamines by Suzuki–Miyaura coupling – scope and limitations

• Thines Kanagasundaram,
• Antje Timmermann,
• Carsten S. Kramer and
• Klaus Kopka

Beilstein J. Org. Chem. 2019, 15, 2569–2576, doi:10.3762/bjoc.15.250

• application in STED (stimulated emission depletion) microscopy, as sensor molecules for, e.g., ions and as fluorophores for the optical imaging of tumors. Different strategies were already employed for their synthesis. Because of just three known literature examples in which Suzuki–Miyaura cross couplings

• in super-resolution microscopy [1][2][3][4][5][6][7][8] and as probes for targeting various biomolecules [9][10][11][12] or sensors for metal ions [13][14][15][16][17], pH [15], voltage [18] or metabolites [19][20][21][22]. Since our group is interested in synthesizing new tumor tracers for

Probing of local polarity in poly(methyl methacrylate) with the charge transfer transition in Nile red

• Aydan Yadigarli,
• Qimeng Song,
• Sergey I. Druzhinin and
• Holger Schönherr

Beilstein J. Org. Chem. 2019, 15, 2552–2562, doi:10.3762/bjoc.15.248

• fluorescence was used to detect a lipid droplet in monkey aortic smooth muscle cells [16], for visualizing different proteins, such as lactoglobulin, casein and albumin [17]. In fluorescence lifetime imaging microscopy τf as a viable contrast parameter was employed to image lipid droplets in living HeLa cells

Ultrafast processes triggered by one- and two-photon excitation of a photochromic and luminescent hydrazone

• Alessandro Iagatti,
• Baihao Shao,
• Alberto Credi,
• Barbara Ventura,
• Ivan Aprahamian and
• Mariangela Di Donato

Beilstein J. Org. Chem. 2019, 15, 2438–2446, doi:10.3762/bjoc.15.236

• ], drug delivery [8][9], design of molecular machines [10][11][12][13], super resolution microscopy [14][15], together with biological applications, among which photopharmacology is currently gaining increasing attention [16][17][18][19]. Photochromic molecules, which respond to light as an external

Targeted photoswitchable imaging of intracellular glutathione by a photochromic glycosheet sensor

• Xianzhi Chai,
• Hai-Hao Han,
• Yi Zang,
• Jia Li,
• Xiao-Peng He,
• Junji Zhang and
• He Tian

Beilstein J. Org. Chem. 2019, 15, 2380–2389, doi:10.3762/bjoc.15.230

• broad and strong absorption makes the 2D MnO2 nanosheets a potential energy acceptor for the fluorophores which are stacked on the nanosheets plane, leading to the fluorescence quenching through FRET mechanism [32][34]. The transmission electron microscopy (TEM) image of the prepared product revealed

Mono- and bithiophene-substituted diarylethene photoswitches with emissive open or closed forms

• A. Lennart Schleper,
• Mariano L. Bossi,
• Vladimir N. Belov and
• Stefan W. Hell

Beilstein J. Org. Chem. 2019, 15, 2344–2354, doi:10.3762/bjoc.15.227

• large fluorescence quantum yield, compound SyOTh1 emerged as a candidate for single-molecule based super-resolution fluorescence microscopy. Keywords: diarylethenes; dyes; fluorescence; organic synthesis; photochromism; photoswitching; Introduction Reversibly photoswitchable diarylethenes (DAEs) with

• asymmetric DAEs with oxidized 2-ethylbenzo[b]thiophene-3-yl units have high cycloreversion quantum yields (a desirable feature for super-resolution RESOLFT microscopy), large Stokes shifts and acceptable absorptivity [5]. Yet unknown asymmetric “thiophenylated” DAEs may have unique properties

• to monothiophene and then to bithiophene derivatives). In all cases, asymmetric substitution allowed faster cycloreversion than symmetric substitution, which is a positive effect regarding potential application of these dyes as reversible fluorescent markers in RESOLFT microscopy [5]. Two processes

Synthesis of a dihalogenated pyridinyl silicon rhodamine for mitochondrial imaging by a halogen dance rearrangement

• Jessica Matthias,
• Thines Kanagasundaram,
• Klaus Kopka and
• Carsten S. Kramer

Beilstein J. Org. Chem. 2019, 15, 2333–2343, doi:10.3762/bjoc.15.226

• microscopy [2][3][4][5][6][7][8][9], as direct probes for various biomolecules [10][11][12][13] or as sensors for metal ions [14][15][16][17][18], pH [16], voltage [19] or metabolites [20][21][22][23]. Several attempts were made, partially supported by DFT calculations, to correlate the dyes’ structural

• different silicon rhodamines. Optimization of the HD rearrangement of 19 and subsequent reaction with xanthone 17 to the silicon rhodamine dye 15. Supporting Information Synthesis of dye 15, its optical characterization and detailed information on microscopy experiments, including videos showing

Fluorescent phosphorus dendrimers excited by two photons: synthesis, two-photon absorption properties and biological uses

• Anne-Marie Caminade,
• Artem Zibarov,
• Eduardo Cueto Diaz,
• Aurélien Hameau,
• Maxime Klausen,
• Kathleen Moineau-Chane Ching,
• Jean-Pierre Majoral,
• Jean-Baptiste Verlhac,
• Olivier Mongin and
• Mireille Blanchard-Desce

Beilstein J. Org. Chem. 2019, 15, 2287–2303, doi:10.3762/bjoc.15.221

• widespread popularity of TPE (also named TPA, for two-photon absorption) in the biology community, with on one side, the advent of two-photon excitation fluorescence microscopy [4], even for research clinical uses [5], and on the other side with the discovery of the TPA properties of quantum dots (inorganic

Aggregation-induced emission effect on turn-off fluorescent switching of a photochromic diarylethene

• Luna Kono,
• Yuma Nakagawa,
• Ayako Fujimoto,
• Ryo Nishimura,
• Yohei Hattori,
• Toshiki Mutai,
• Nobuhiro Yasuda,
• Kenichi Koizumi,
• Satoshi Yokojima,
• Shinichiro Nakamura and
• Kingo Uchida

Beilstein J. Org. Chem. 2019, 15, 2204–2212, doi:10.3762/bjoc.15.217

• , fluorescence switching for molecular level recording [4], multiple-fluorescence for logic circuits [5] as well as biological applications [6] and super-resolution microscopy for bio-imaging [7][8]. The fluorescence switching in solid state is attracting much attention from both scientific and technological

Bipolenins K–N: New sesquiterpenoids from the fungal plant pathogen Bipolaris sorokiniana

• Chin-Soon Phan,
• Hang Li,
• Simon Kessler,
• Peter S. Solomon,
• Andrew M. Piggott and
• Yit-Heng Chooi

Beilstein J. Org. Chem. 2019, 15, 2020–2028, doi:10.3762/bjoc.15.198

• research was undertaken with the assistance of resources and services from the National Computational Infrastructure (NCI), which is supported by the Australian Government. Authors acknowledge the facilities of Microscopy Australia at the Centre for Microscopy, Characterisation & Analysis, The University

Archangelolide: A sesquiterpene lactone with immunobiological potential from Laserpitium archangelica

• Silvie Rimpelová,
• Michal Jurášek,
• Lucie Peterková,
• Jiří Bejček,
• Vojtěch Spiwok,
• Miloš Majdl,
• Michal Jirásko,
• Miloš Buděšínský,
• Juraj Harmatha,
• Eva Kmoníčková,
• Pavel Drašar and
• Tomáš Ruml

Beilstein J. Org. Chem. 2019, 15, 1933–1944, doi:10.3762/bjoc.15.189

• , the endoplasmic reticulum was visualized by transfection with a plasmid DNA coding mCherry-ER (0.5 µg) using Fugene HD (Promega, USA; DNA/Fugene HD = 1:3). Fluorescence microscopy The intracellular localization of compound 5 was studied by real-time live-cell fluorescence microscopy using an inverse

• sesquiterpene lactones archangelolide (1) and trilobolide (2). Intracellular localization of archangelolide-dansyl (5) in human cells from osteosarcoma (U-2 OS). A, C) Bright-field images; B, D) fluorescence microscopy of living cells treated with 1 µM concentration of compound 5 for 90 min. Co-localization of

• dansylarchangelolide 5 with a marker of endoplasmic reticulum (top row) and with a mitochondrial marker (bottom row) in human cells from osteosarcoma (U-2 OS). A, E) Bright-field images. Fluorescence microscopy of living cells treated with 1 µM concentration of compound 5 (90 min; images B and F) and a mitochondria

Morphology-tunable and pH-responsive supramolecular self-assemblies based on AB₂-type host–guest-conjugated amphiphilic molecules for controlled drug delivery

• Yang Bai,
• Cai-ping Liu,
• Di Chen,
• Long-hai Zhuo,
• Huai-tian Bu and
• Wei Tian

Beilstein J. Org. Chem. 2019, 15, 1925–1932, doi:10.3762/bjoc.15.188

• -assembly and the size of β-CD-BM2-based supramolecular self-assemblies under neutral and acidic pH were first investigated by employing transmission electron microscopy (TEM) and dynamic light scattering (DLS). The prepared β-CD-BM2 were dissolved under neutral pH solution to form FSSAs. TEM revealed that

• -loaded supramolecular self-assemblies Confocal laser scanning microscopy (CLSM) was further utilized to confirm the intracellular uptake of DOX-loaded FSSAs (Figure 6). The PC-3 cells treated with DOX-loaded FSSAs indicated Hoechst 33342 blue fluorescence in their nuclei and DOX red fluorescence in their

Nanopatterns of arylene–alkynylene squares on graphite: self-sorting and intercalation

• Tristan J. Keller,
• Joshua Bahr,
• Kristin Gratzfeld,
• Nina Schönfelder,
• Marcin A. Majewski,
• Marcin Stępień,
• Sigurd Höger and
• Stefan-S. Jester

Beilstein J. Org. Chem. 2019, 15, 1848–1855, doi:10.3762/bjoc.15.180

• , Uniwersytet Wrocławski, ul. F. Joliot-Curie 14, 50-383 Wrocław, Poland 10.3762/bjoc.15.180 Abstract Supramolecular nanopatterns of arylene–alkynylene squares with side chains of different lengths are investigated by scanning tunneling microscopy at the solid/liquid interface of highly oriented pyrolytic

• and non-planar coronoid polycyclic aromatic hydrocarbons (i.e., butyloxy-substituted kekulene and octulene derivatives) are found to be able to intercalate into the intramolecular nanopores. Keywords: macrocycles; scanning tunneling microscopy; self-assembled monolayers; self-sorting; solid/liquid

• tunneling microscopy (STM). Throughout all STM images, surface regions covered by arylene–alkynylene backbones and (intermolecularly interdigitating) alkoxy side chains appear in bright and dark colors, which indicate high and low tunneling currents, respectively [31]. In most of our STM images, we achieve

Norbornadiene-functionalized triazatriangulenium and trioxatriangulenium platforms

• Roland Löw,
• Talina Rusch,
• Tobias Moje,
• Fynn Röhricht,
• Olaf M. Magnussen and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1815–1821, doi:10.3762/bjoc.15.175

• as realized in compound 1. Consequently, future surface chemistry investigations will be performed with compound 1 including the TATA platform and an ethynyl spacer. STM Measurements The adsorption behaviour of the NBD 1a on Au(111) surfaces was studied by scanning tunnelling microscopy (STM) at room

Synthesis and conformational preferences of short analogues of antifreeze glycopeptides (AFGP)

• Małgorzata Urbańczyk,
• Michał Jewgiński,
• Joanna Krzciuk-Gula,
• Jerzy Góra,
• Rafał Latajka and
• Norbert Sewald

Beilstein J. Org. Chem. 2019, 15, 1581–1591, doi:10.3762/bjoc.15.162

• into the ice lattice [12], others investigated the adsorption process on different surfaces via atomic force microscopy [10][13][14]. The antifreeze activity has been correlated with long-range perturbation of hydration dynamics [15]. Latest molecular dynamics simulations suggest that AFGP reversibly

Reversible end-to-end assembly of selectively functionalized gold nanorods by light-responsive arylazopyrazole–cyclodextrin interaction

• Maximilian Niehues,
• Patricia Tegeder and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2019, 15, 1407–1415, doi:10.3762/bjoc.15.140

• semi-micro PMMA cuvettes (BRAND). Transmission electron microscopy was performed using a Titan Themis G3 300 TEM (FEI) operating at 300 kV or a Libra 200 FE electron microscope (Zeiss) operating at 200 kV. The ζ-potential measurements were carried out on a Nano ZS Zetasizer (Malvern Instruments) at 25

Complexation of a guanidinium-modified calixarene with diverse dyes and investigation of the corresponding photophysical response

• Yu-Ying Wang,
• Yong Kong,
• Zhe Zheng,
• Wen-Chao Geng,
• Zi-Yi Zhao,
• Hongwei Sun and
• Dong-Sheng Guo

Beilstein J. Org. Chem. 2019, 15, 1394–1406, doi:10.3762/bjoc.15.139

• opportunity to construct organic luminescent materials and could be engaged in the manufacture of high-performance supramolecular dye lasers [24][48]. The complexation of GC5A with the two-photon fluorescent probe Two-photon excitation microscopy is a fluorescence imaging technique utilizing near-infrared

• photons as the excitation source. The fluorescent probe simultaneously absorbs two low energy photons to reach the excited state followed by fluorescence [57]. Acedan (6-acetyl-2-(dimethylamino)naphthalene) is a well-known probe with two-photon absorption that has been utilized in two-photon microscopy

• azocalix[4]arene with rhodamine 123 as the reporter pair [16]. Consequently, with regard to bioimaging, the study of the complexation between macrocycles and two-photon probes is meaningful as two-photon excitation microscopy exhibits several distinct advantages including a deeper tissue penetration

Selenophene-containing heterotriacenes by a C–Se coupling/cyclization reaction

• Pierre-Olivier Schwartz,
• Sebastian Förtsch,
• Astrid Vogt,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2019, 15, 1379–1393, doi:10.3762/bjoc.15.138

• the steady growth of polymer film. After 20 sweeps, homogeneous films of polymers P1–P4 were obtained (observed by optical microscopy) which were then electrochemically and spectroelectrochemically characterized (Table 5 and Table S7 in Supporting Information File 1). Cyclic voltammograms of polymers

N-doped carbon dots covalently functionalized with pillar[5]arenes for Fe³⁺ sensing

• Jia Gao,
• Ming-Xue Wu,
• Dihua Dai,
• Zhi Cai,
• Yue Wang,
• Wenhui Fang,
• Yan Wang and
• Ying-Wei Yang

Beilstein J. Org. Chem. 2019, 15, 1262–1267, doi:10.3762/bjoc.15.123

• microscopy (TEM) (Figure 1a). TEM images showed the spherical shape of CCDs with a diameter of 9 nm. For comparison, the shape of CN-dots was quasi-spherical with an average diameter of 7 nm (Figure 1b). As shown in Figure 1c, the UV–vis absorption peak of CN-dots is at 340 nm, and CP[5] has an obvious UV

Self-assembly behaviors of perylene- and naphthalene-crown macrocycle conjugates in aqueous medium

• Xin Shen,
• Bo Li,
• Tiezheng Pan,
• Jianfeng Wu,
• Yangxin Wang,
• Jie Shang,
• Yan Ge,
• Lin Jin and
• Zhenhui Qi

Beilstein J. Org. Chem. 2019, 15, 1203–1209, doi:10.3762/bjoc.15.117

•  1d). In the polar solvents MeCN and MeOH, fluorescence of 2 becomes much weaker, and is almost totally quenched in H2O. In order to observe the aggregates formed by 1 and 2 visually in solutions, transmission electron microscopy (TEM) was utilized. First, the aggregates of 1 formed in CHCl3 and MeCN