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

Mechanochemical synthesis of hyper-crosslinked polymers: influences on their pore structure and adsorption behaviour for organic vapors

• Sven Grätz,
• Sebastian Zink,
• Hanna Kraffczyk,
• Marcus Rose and
• Lars Borchardt

Beilstein J. Org. Chem. 2019, 15, 1154–1161, doi:10.3762/bjoc.15.112

• contents below the limit of detection (Supporting Information File 1, Figure S3). Scattering electron microscopy also revealed an agglomerated morphology of the samples (Supporting Information File 1, Figure S4). After successfully establishing the occurrence of the cross-linking reaction and investigating

• . Scanning electron microscopy (SEM/EDX) images were obtained using a Hitachi SU8020 SEM equipped with a secondary electron (SE) detector. Prior to the measurement the samples were prepared on an adhesive carbon pad and sputtered with gold to obtain the necessary electron conductivity. Thermogravimetric

Photochemical generation of the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radical from caged nitroxides by near-infrared two-photon irradiation and its cytocidal effect on lung cancer cells

• Ayato Yamada,
• Manabu Abe,
• Yoshinobu Nishimura,
• Shoji Ishizaka,
• Masashi Namba,
• Taku Nakashima,
• Kiyofumi Shimoji and
• Noboru Hattori

Beilstein J. Org. Chem. 2019, 15, 863–873, doi:10.3762/bjoc.15.84

• light using a fluorescence microscope (BIOREVO BZ-9000, Keyence, Osaka, Japan), intracellular ROS were detected using the ROS-ID Oxidative Stress Detection Kit (Enzo Life Sciences, Farmingdale, NY, USA) in conjunction with fluorescence microscopy. Intracellular ROS was detected in the form of green

Synthesis of acylglycerol derivatives by mechanochemistry

• Karen J. Ardila-Fierro,
• Andrij Pich,
• Marc Spehr,
• José G. Hernández and
• Carsten Bolm

Beilstein J. Org. Chem. 2019, 15, 811–817, doi:10.3762/bjoc.15.78

• peptides to endure mechanical stress in nature has allured scientists to evaluate the mechanical stability of proteins by using single-molecule nanomechanical techniques (e.g., magnetic and optical tweezers or atomic force microscopy) [3][4]. Additionally, the resilience of the peptide bond to mechanical

The LANCA three-component reaction to highly substituted β-ketoenamides – versatile intermediates for the synthesis of functionalized pyridine, pyrimidine, oxazole and quinoxaline derivatives

• Tilman Lechel,
• Roopender Kumar,
• Mrinal K. Bera,
• Reinhold Zimmer and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2019, 15, 655–678, doi:10.3762/bjoc.15.61

• this experiment was the double-coupling product OX27 and the mono-coupling product (not shown) was isolated in 5% yield [45]. A solution of the C3-symmetric compound OX28 in 1-phenyloctane was investigated by scanning tunneling microscopy (STM) to reveal its ability to form self-assembled monolayers at

Cyclopropene derivatives of aminosugars for metabolic glycoengineering

• Jessica Hassenrück and
• Valentin Wittmann

Beilstein J. Org. Chem. 2019, 15, 584–601, doi:10.3762/bjoc.15.54

• were incubated with Tz-biotin, followed by incubation with streptavidin-AlexaFluor 555 (strep-AF555) for visualization (Scheme 1). In confocal fluorescence microscopy experiments, all sugars showed a distinct cell membrane staining in comparison to the negative control (Figure 3A). As expected [25][27

• , resuspended in buffer, and then subjected to flow cytometry analysis. The obtained results coincided with those of the fluorescence microscopy experiments (Figure 3B,C). Ac4ManNCyc gave a significantly higher fluorescence intensity than the negative control, which, however, is exceeded by far from that of

• . Ac4GlcNCp was obtained in 19% yield and Ac4GalNCp in 16% yield over two steps. We next explored the suitability of Ac4GlcNCp and Ac4GalNCp in MGE. Applying the same protocol used for the mannosamine derivatives, we first performed fluorescence microscopy experiments after MGE. As a positive control, we

Synthesis of the polyketide section of seragamide A and related cyclodepsipeptides via Negishi cross coupling

• Jan Hendrik Lang and
• Thomas Lindel

Beilstein J. Org. Chem. 2019, 15, 577–583, doi:10.3762/bjoc.15.53

• A (1, Scheme 1) [1][2], is an ideal situation for the validation of the chemoselectivity and efficiency of photoaffinity labelling. Recently, it has been determined by cryo-electron microscopy how jasplakinolide A (1) binds to F-actin and alters the actin skeleton in vivo, resulting in pronounced

Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines

• Andrejs Šišuļins,
• Jonas Bucevičius,
• Yu-Ting Tseng,
• Irina Novosjolova,
• Kaspars Traskovskis,
• Ērika Bizdēna,
• Huan-Tsung Chang,
• Sigitas Tumkevičius and
• Māris Turks

Beilstein J. Org. Chem. 2019, 15, 474–489, doi:10.3762/bjoc.15.41

• biocompatibility could be applied for the cell staining in fluorescence microscopy. Applications in the cell studies The newly prepared compound library with purine and 7-deazapurine derivatives was submitted to the screening of their biological activity. The compounds of interest were studied on two cancer cell

Fabrication of supramolecular cyclodextrin–fullerene nonwovens by electrospinning

• Hiroaki Yoshida,
• Ken Kikuta and
• Toshiyuki Kida

Beilstein J. Org. Chem. 2019, 15, 89–95, doi:10.3762/bjoc.15.10

• ). Because the red photoluminescence of C60 is useful for a bioimaging applications [30][31], the electrospun fibers were measured with confocal laser scanning microscopy (CLSM). Interestingly, a uniform red color distribution is observed (Figure S9, in Supporting Information File 1), indicating the presence

Lectins of Mycobacterium tuberculosis – rarely studied proteins

• Katharina Kolbe,
• Sri Kumar Veleti,
• Norbert Reiling and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2019, 15, 1–15, doi:10.3762/bjoc.15.1

• regarded as a non-piliated genus; however, recently, studies using transmission electron microscopy (TEM) and atomic force microscopy (AFP) have identified long appendages on the surfaces of M. smegmatis and Mtb, which could be identified as pili [108][109][110]. Two different pili types were detected for

• microscopy as rope-like bundles on the cell surface. Mature T4P are encoded by a seven gene operon, the expression of which is up-regulated during contact with A549 epithelial cells and within macrophages [111][129]. However, their significance in Mtb pathogenicity has hitherto not been further investigated

Repurposing the anticancer drug cisplatin with the aim of developing novel Pseudomonas aeruginosa infection control agents

• Mingjun Yuan,
• Song Lin Chua,
• Yang Liu,
• Daniela I. Drautz-Moses,
• Joey Kuok Hoong Yam,
• Thet Tun Aung,
• Roger W. Beuerman,
• May Margarette Santillan Salido,
• Stephan C. Schuster,
• Choon-Hong Tan,
• Michael Givskov,
• Liang Yang and
• Thomas E. Nielsen

Beilstein J. Org. Chem. 2018, 14, 3059–3069, doi:10.3762/bjoc.14.284

• incubation of the macrophages at 37 °C, 5% CO2 for 4 h was ensued. A solution containing 20 µM propidium iodide (PI) was added to the macrophages to stain for dead macrophages killed by PAO1 treated with cisplatin or ΔpscJ. Live and dead macrophages were imaged by fluorescence microscopy (Zeiss, Germany) at

Novel solid-phase strategy for the synthesis of ligand-targeted fluorescent-labelled chelating peptide conjugates as a theranostic tool for cancer

• Sagnik Sengupta,
• Mena Asha Krishnan,
• Premansh Dudhe,
• Ramesh B. Reddy,
• Bishnubasu Giri,
• Sudeshna Chattopadhyay and
• Venkatesh Chelvam

Beilstein J. Org. Chem. 2018, 14, 2665–2679, doi:10.3762/bjoc.14.244

• bioconjugates a potential theranostic tool for cancer. The newly synthesized bioconjugates 13 and 17, that can selectively target PSMA+ and FR+ cancers, were further evaluated by performing in vitro studies using laser scanning confocal microscopy on PSMA+ LNCaP cells, FR+ epithelial CHO-β cells and PSMA−, FR

• folate receptors. The in vitro uptake study has been performed using laser scanning confocal microscopy and the bioconjugates are found to be delivered specifically to cells expressing corresponding cell surface proteins. The small molecule targeted imaging probes prepared in this study are designed for

• remove unbound conjugates, confocal images were acquired using a laser scanning confocal microscopy (FV 1000, Olympus) by excitation at 559 nm (yellow diode laser) and emission at 618 nm. Author’s Contributions Sagnik Sengupta (SS) chemically synthesized and characterized the targeting ligands and

Impact of Pseudomonas aeruginosa quorum sensing signaling molecules on adhesion and inflammatory markers in endothelial cells

• Carmen Curutiu,
• Florin Iordache,
• Veronica Lazar,
• Aurelia Magdalena Pisoschi,
• Aneta Pop,
• Mariana Carmen Chifiriuc and
• Alina Maria Hoban

Beilstein J. Org. Chem. 2018, 14, 2580–2588, doi:10.3762/bjoc.14.235

• cellular substrata of PAO1 strain treated with 20 µM of tested purified QSSMs. Fluorescence microscopy images of QSSMs treated euckariote cells, revealing attachment patterns. (Ctrl- = untreated control cells, P.a ctrl = P. aeruginosa control treated cells, ODdHL = P. aeruginosa + OddHL treated cells

Comparative cell biological study of in vitro antitumor and antimetastatic activity on melanoma cells of GnRH-III-containing conjugates modified with short-chain fatty acids

• Eszter Lajkó,
• Sarah Spring,
• Rózsa Hegedüs,
• Beáta Biri-Kovács,
• Sven Ingebrandt,
• Gábor Mező and
• László Kőhidai

Beilstein J. Org. Chem. 2018, 14, 2495–2509, doi:10.3762/bjoc.14.226

• cancer cell behavior and effects of targeted chemotherapeutics with small structural differences (e.g., length of the side chain in 4Lys) was also clearly suggested. Keywords: drug-targeting conjugates; gonadotropin-releasing hormone-III; holographic microscopy; impedimetry; short-chain fatty acids

• concentration. This apparent lack of consistence between the results of impedimetry and the basic morphometric parameters provided by holographic microscopy can be attributed to some method- and cell-related factors. The change in impedance (Cell index) during cell adhesion depends on (i) the cell–cell

• cell movement or locomotion) of conjugates were investigated by monitoring the locomotion of A2058 cells with holographic microscopy under the condition that the conjugates (10−7 to 10−5 M) were added directly to the cells in a uniform concentration. For the characterization of cellular movement, three

Bioinspired cobalt cubanes with tunable redox potentials for photocatalytic water oxidation and CO₂ reduction

• Zhishan Luo,
• Yidong Hou,
• Jinshui Zhang,
• Sibo Wang and
• Xinchen Wang

Beilstein J. Org. Chem. 2018, 14, 2331–2339, doi:10.3762/bjoc.14.208

• spectrometer with KBr as the diluents. Electrochemical measurements were conducted with a Biologic VSP-300 Electrochemical System in a conventional three electrode cell. The 1H NMR experiments were performed on Bruker AVANCE 400M spectrometers. Transmission electron microscopy (TEM) was obtained using a FEI

Tetrathiafulvalene – a redox-switchable building block to control motion in mechanically interlocked molecules

• Hendrik V. Schröder and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2018, 14, 2163–2185, doi:10.3762/bjoc.14.190

• ][89]. An ordered array of molecules enables the possibility of concerted switching. The fixed orientation on a surface allows studying molecules with sophisticated techniques such as scanning tunneling microscopy. Furthermore, redox-switchable AMMs, containing for example TTF moieties, can be

Synthesis and supramolecular self-assembly of glutamic acid-based squaramides

• Juan V. Alegre-Requena,
• Marleen Häring,
• Isaac G. Sonsona,
• Alex Abramov,
• Eugenia Marqués-López,
• Raquel P. Herrera and
• David Díaz Díaz

Beilstein J. Org. Chem. 2018, 14, 2065–2073, doi:10.3762/bjoc.14.180

• aliphatic chain and on the other side to a glutamic acid residue. The gelator bearing the free carboxylic groups showed a lower gelation capacity than its precursor diester derivative. Some selected gels were further studied by infrared spectroscopy, rheology and electron microscopy. Critical gelation

• –780 nm), which was later supported by electron microscopy (see below). Moreover, the gels displayed full thermoreversibility and remained stable for at least two months when stored in sealed vials. Only the gel made in DMF showed a gradual gel-to-crystal transition [37][38], which is not surprising

• organogels were conducted by field emission scanning electron microscopy (FESEM) of the corresponding xerogels obtained by the freeze-drying method (Figure 4). The remarkable influence of the solvents on the morphologies was evident among different samples. For instance, the specimens prepared in ethyl

Functionalization of graphene: does the organic chemistry matter?

• Artur Kasprzak,
• Agnieszka Zuchowska and
• Magdalena Poplawska

Beilstein J. Org. Chem. 2018, 14, 2018–2026, doi:10.3762/bjoc.14.177

• for functionalized GO: 1639 cm−1). This unexpected statement was supported, not by further spectroscopic analyses, but by morphological studies (transmission electron microscopy (TEM) and atomic force microscopy (AFM)) only. Once again, the possible electrostatic adsorption or hydrogen bonding

A self-assembled photoresponsive gel consisting of chiral nanofibers

• Lei Zou,
• Dan Han,
• Zhiyi Yuan,
• Dongdong Chang and
• Xiang Ma

Beilstein J. Org. Chem. 2018, 14, 1994–2001, doi:10.3762/bjoc.14.174

• absorption spectroscopy, circular dichroism, scanning electron microscopy and rheological techniques. This work provides a new method for facile synthesis of chiro-optical gels. Keywords: chirality; nanostructure; organogel; photoresponse; self-assembly; Introduction Supramolecular gels [1][2] immobilized

• microscopy (SEM, Figure 4). The samples were prepared by evaporating the solution of compound 3 on a surface of mica, and the differences in various solvents were also investigated. The sample in DMSO did not show a chiral self-assembled nanostructure owing to the destruction of quadruple hydrogen bonding

• to the character of the gel. However, the gel is not stable under shaking, where it is broken into a mixture of solution and small pieces. After melting these particles again then natural cooling, the gel state was once again obtained. Field emission scanning electron microscopy (FESEM) was utilized

Rational design of boron-dipyrromethene (BODIPY) reporter dyes for cucurbit[7]uril

• Mohammad A. Alnajjar,
• Jürgen Bartelmeß,
• Robert Hein,
• Pichandi Ashokkumar,
• Mohamed Nilam,
• Werner M. Nau,
• Knut Rurack and
• Andreas Hennig

Beilstein J. Org. Chem. 2018, 14, 1961–1971, doi:10.3762/bjoc.14.171

• illumination in confocal laser scanning microscopy [23][25], or absorb at shorter wavelengths, where biological samples show a high background from autofluorescence [26][27]. An ideal fluorescent dye would be highly photostable in biological media, have long-wavelength absorption to minimize background

• BODIPYs introduced herein matches the emission wavelength of an Ar laser, which is still the most common excitation source in fluorescence correlation spectroscopy (FCS) and fluorescence microscopy. FCS has been established to study dynamic processes in biological systems and, more recently, also in

• complex formation of the BODIPY core, the photostability of the dyes was not affected by CB7 complex formation (Figure S20, Supporting Information File 1). The compatibility of BODIPYs with common excitation sources and filter sets also enables their use in fluorescence microscopy. To demonstrate, we have

Graphitic carbon nitride prepared from urea as a photocatalyst for visible-light carbon dioxide reduction with the aid of a mononuclear ruthenium(II) complex

• Kazuhiko Maeda,
• Daehyeon An,
• Ryo Kuriki,
• Daling Lu and
• Osamu Ishitani

Beilstein J. Org. Chem. 2018, 14, 1806–1812, doi:10.3762/bjoc.14.153

• Kα radiation), Fourier-transform infrared (FTIR) spectroscopy (FTIR-610, Jasco), transmission electron microscopy (TEM) (JEM-2010F, JEOL), and UV–visible diffuse reflectance spectroscopy (DRS) (V-565, Jasco). The Brunauer–Emmett–Teller (BET) surface area of each specimen was determined using a