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

• widely used in the dye industry and have been applied as advanced materials in the fields of fluorescence labeling [58][59], organic semiconducting devices [60][61], and light harvesting [62][63][64][65]. PDI and NDI units have been extensively incorporated into functional supramolecular architectures

Precious metal-free molecular machines for solar thermal energy storage

• Meglena I. Kandinska,
• Snejana M. Kitova,
• Vladimira S. Videva,
• Stanimir S. Stoyanov,
• Stanislava B. Yordanova,
• Stanislav B. Baluschev,
• Silvia E. Angelova and
• Aleksey A. Vasilev

Beilstein J. Org. Chem. 2019, 15, 1096–1106, doi:10.3762/bjoc.15.106

• . First of all, the azacrown nitrogen atom is linked directly to the dye and it is part of the chromophore system, responsible for the “push–pull” effect and the photophysical properties of the dye. This provides control over the “push–pull” effect in the chromophore by switching on and off states (i.e

• defined their photophysical behavior in neat acetonitrile (ACN) solution and in the presence of barium cations. Figure 1 shows the absorption spectra of dyes 4a–d measured at different concentrations (cM) of Ba(ClO4)2. All dye solutions have similar absorption profiles with a broad long wavelength band in

• chromoionophore and the spectra in Figure 1 were assigned to the formation of the trans-dye–Ba2+ complex [19]. For all dye solutions, a distinct isosbestic point upon titration was observed, indicating only one kind of complex formation even at the highest Ba2+ concentration. To determine the optimal Ba2

Molecular recognition using tetralactam macrocycles with parallel aromatic sidewalls

• Dong-Hao Li and
• Bradley D. Smith

Beilstein J. Org. Chem. 2019, 15, 1086–1095, doi:10.3762/bjoc.15.105

• enables them to be effective hosts for a wide range of guest molecules including organic biscarbonyl derivatives, near-infrared dyes, acenes, precious metal halide complexes, trimethylammonium ion-pairs, and saccharides. Keywords: fluorescent dye; host–guest chemistry; hydrogen bonding; hydrophobic

• acene guests Rotaxane template 18 in Scheme 2 is a squaraine dye whose central core has two oxygen atoms that can form hydrogen bonds with the tetralactam NH residues. Squaraine rotaxanes were first prepared by the Smith group in 2005 using the Leigh-type clipping method [44]. As a general trend the

• photophysical property of a squaraine dye is improved when it is encapsulated by tetralactam A, B, or C, but squaraine fluorescence is quenched when the dye is encapsulated by tetralactam E whose structure has extremely electron-rich sidewalls [34]. The moderate flexibility of tetralactam A is one of the

Fabrication, characterization and adsorption properties of cucurbit[7]uril-functionalized polycaprolactone electrospun nanofibrous membranes

• Changzhong Chen,
• Fengbo Liu,
• Xiongzhi Zhang,
• Zhiyong Zhao and
• Simin Liu

Beilstein J. Org. Chem. 2019, 15, 992–999, doi:10.3762/bjoc.15.97

• blue (MB) is frequently used as a routine model dye molecule to test the adsorption capability of materials. More importantly, the binding constant of MB with CB[7] is as high as 107 M−1 in aqueous solution [33]. However, due to the considerable solubility of CB[7] in water, the adsorption experiment

• isotherm fitted the Langmuir isotherm model. Although the adsorption capability of the nanofibrous membranes was low due to weak binding between CB[7] and the dye molecule, it was greatly improved with the addition of CB[7]. Currently the fabrication of CB[n]s linked covalently on rigid polymeric matrices

Diaminoterephthalate–α-lipoic acid conjugates with fluorinated residues

• Leon Buschbeck,
• Aleksandra Markovic,
• Gunther Wittstock and
• Jens Christoffers

Beilstein J. Org. Chem. 2019, 15, 981–991, doi:10.3762/bjoc.15.96

• sequence including one deprotection reaction. One functional unit is α-lipoic acid (ALA) for binding the dye to gold surfaces. It was introduced to the DAT scaffold by an amidation reaction. The other functional unit is a para-(trifluoromethyl)benzyl group for facile detection of the surface-bound material

• indicated that trifluoromethylation is an excellent tool for the detection of surface-bound materials by XPS. Keywords: chromophore; diaminoterephthalate; fluorine surface marker; fluorescence dye; lipoic acid; self-assembled monolayers; Introduction Diaminoterephthalates (DATs) are powerful fluorescence

• suitability for molecular surface labeling. Conclusion Two bifunctional diaminoterephthalate (DAT) fluorescence dyes have been prepared. One functional unit is α-lipoic acid (ALA) for binding the dye to gold surfaces. The other carries a trifluoromethyl group for facile detection of the surface-bound material

Synthesis of (macro)heterocycles by consecutive/repetitive isocyanide-based multicomponent reactions

• Angélica de Fátima S. Barreto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2019, 15, 906–930, doi:10.3762/bjoc.15.88

• -MiB. Functional macrocycles have been developed with dye-modified and photoswitchable moieties by MiBs [43]. The approach employed the use of bifunctionalized near-infrared (NIR) dyes containing two carboxylic acid moieties with diisocyanide building blocks providing the formation of somewhat flexible

• macrocycles [40]. Synthesis of cholane-based hybrid macrolactams by MiBs [41]. Synthesis of macrocyclic oligoimine-based DCL using the Ugi-4CR-based quenching approach [42]. Dye-modified and photoswitchable macrocycles by MiBs [43]. Synthesis of nonsymmetric cryptands by two sequential double Ugi-4CR-based

Design and synthesis of multivalent α-1,2-trimannose-linked bioerodible microparticles for applications in immune response studies of Leishmania major infection

• Chelsea L. Rintelmann,
• Tara Grinnage-Pulley,
• Kathleen Ross,
• Daniel E. K. Kabotso,
• Angela Toepp,
• Anne Cowell,
• Christine Petersen,
• Balaji Narasimhan and
• Nicola Pohl

Beilstein J. Org. Chem. 2019, 15, 623–632, doi:10.3762/bjoc.15.58

• of the commercially available rhodamine dye, TAMRA (555ex/580em), to the dendrimer would allow for standard immunofluorescence assays, to track the microparticle following cellular uptake and intracellular processing. TAMRA’s high photostability, low pH sensitivity and ease of incorporation through

Low-budget 3D-printed equipment for continuous flow reactions

• Jochen M. Neumaier,
• Amiera Madani,
• Thomas Klein and
• Thomas Ziegler

Beilstein J. Org. Chem. 2019, 15, 558–566, doi:10.3762/bjoc.15.50

• . The shape of the channels is a square with 1.2 mm × 1.2 mm diameter and the reactor has a total volume of 1.05 mL. It was designed to have two initial inlets with a subsequent chaotic mixing zone [27] and one quench inlet. We chose two dye solutions in dichloromethane for mixing experiments as a model

• system. a) CAD drawing of the reactor R1. b) 3D-printed reactor R1 from the CAD drawing. The reactor is filled with a blue dye solution for better visibility of the channels. c) Early stage prototype of a 3D-printed flow reactor (R2). d) Mixing test of two dye solutions. a) L-shaped rail made of PLA with

• the mounted reactor R3. The small picture shows the fixed reactor in the rail. b) In-printed screw nuts during 3D-printing: The print was paused, the nuts inserted and the print resumed. a) Microreactor R4 with a reactor volume of 12 µL filled with a blue dye solution. b) Magnification of the reactor

Synthesis and SAR of the antistaphylococcal natural product nematophin from Xenorhabdus nematophila

• Frank Wesche,
• Hélène Adihou,
• Thomas A. Wichelhaus and
• Helge B. Bode

Beilstein J. Org. Chem. 2019, 15, 535–541, doi:10.3762/bjoc.15.47

• relationship of the simple and antistaphylococcal amide nematophin from Xenorhabdus nematophila and synthetic derivatives are described. Moreover, the synthesis of intrinsic fluorescent derivatives, incorporating azaindole moieties was achieved for the first time. Keywords: azaindole; fluorescent dye; MRSA

New standards for collecting and fitting steady state kinetic data

• Kenneth A. Johnson

Beilstein J. Org. Chem. 2019, 15, 16–29, doi:10.3762/bjoc.15.2

• concentration of active sites. There are significant systematic errors in measurements of protein concentrations using dye-binding assays or by absorbance measurements, and the fraction of protein that is active is not known without direct measurement. For these reasons, it is important to perform an active

Organometallic vs organic photoredox catalysts for photocuring reactions in the visible region

• Aude-Héloise Bonardi,
• Frédéric Dumur,
• Guillaume Noirbent,
• Jacques Lalevée and
• Didier Gigmes

Beilstein J. Org. Chem. 2018, 14, 3025–3046, doi:10.3762/bjoc.14.282

• )iridium(III) reported in ref [37] for photocontrolled radical polymerization of methacrylates. The use of a Fe complex or dye (for metal-free PC) is also possible to performed ATRP as described in reference [107]. A ROMP mechanism is also possible thanks to the photoredox catalyst. ROMP stands for ring

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

• affinity of the PSMA-targeting conjugate 13; it minimizes the repulsive interaction between the bulky dye molecule and the targeted folate protein active site in the case of folate receptor targeting bioconstruct 17, (iii) a fluorescent tag to track the cellular destination of bioconjugates and

Targeting the Pseudomonas quinolone signal quorum sensing system for the discovery of novel anti-infective pathoblockers

• Christian Schütz and
• Martin Empting

Beilstein J. Org. Chem. 2018, 14, 2627–2645, doi:10.3762/bjoc.14.241

• facilitated the discovery of novel PqsD-targeting compounds through CuAAC-mediated conjugation of a fluorescent dye (Figure 9) [62]. Finally, Sangshetti et al. reported the discovery of linezolid-like Schiff bases, which showed promising anti-biofilm activity in the double-digit micromolar range [63]. Notably

Synthesis of aryl sulfides via radical–radical cross coupling of electron-rich arenes using visible light photoredox catalysis

• Amrita Das,
• Mitasree Maity,
• Simon Malcherek,
• Burkhard König and
• Julia Rehbein

Beilstein J. Org. Chem. 2018, 14, 2520–2528, doi:10.3762/bjoc.14.228

• ). The organic dye 9-mesityl-10-phenylacridinium tetrafluoroborate completely decomposed in the presence of excess disulfide within 30 minutes of irradiation. [Ir(dF(CF3)ppy)2(dtbpy)]PF6 was found to be the best photocatalyst and in this case, CH3CN was the best solvent compared to DMF, DMSO and DCE

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

• -250TM, ChemoMetec A/S, Lillerød, Denmark) using Vitabright-48™ (ChemoMetec A/S, Lillerød, Denmark), a cell permeable dye that reacts with thiol groups to form a fluorescent product. An inverse correlation has been shown between the concentration of thiols and progression of apoptosis; the level of

• thiols, and hence the fluorescence intensity of this dye decrease in response to induction of apoptosis [44]. Based on the percentages of apoptotic cells shown in Table 4, there was a good match between the values provided by these two different methods. As expected, the maximum apoptotic effect was

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

• after 3 h reaction in each case is due to photobleaching of the used dye photosensitizer. Moreover, after water oxidation and CO2 reduction reactions, the structures of 1-CN and 1-OMe were studied by 1H NMR spectroscopy, and no obvious changes were observed compared with the fresh samples (Supporting

Hydroarylations by cobalt-catalyzed C–H activation

• Rajagopal Santhoshkumar and
• Chien-Hong Cheng

Beilstein J. Org. Chem. 2018, 14, 2266–2288, doi:10.3762/bjoc.14.202

• limited to terminal alkynes. Additionally, they applied this methodology to design a mitochondria-targeted imaging dye from electron-withdrawing formyl-substituted indoles and alkynes. Later, Maji’s group reported an N-tert-butyl amide-directed mono- and di-alkenylation reactions using a cobalt catalyst

Synthesis of new p-tert-butylcalix[4]arene-based polyammonium triazolyl amphiphiles and their binding with nucleoside phosphates

• Vladimir A. Burilov,
• Guzaliya A. Fatikhova,
• Mariya N. Dokuchaeva,
• Ramil I. Nugmanov,
• Diana A. Mironova,
• Pavel V. Dorovatovskii,
• Victor N. Khrustalev,
• Svetlana E. Solovieva and
• Igor S. Antipin

Beilstein J. Org. Chem. 2018, 14, 1980–1993, doi:10.3762/bjoc.14.173

• pyrene and eosin Y as dye probes. The CAC values of tetraalkyl-substituted macrocycles 12a,b (5 µM for both) are significantly lower than those for dialkyl-substituted macrocycles 10a,b (790 and 160 µM, respectively). Premicellar aggregates of macrocycles 10a,b and 12a,b with the dye eosin Y were used

• for nucleotides sensing through a dye replacement procedure. It is unusual that disubstituted macrocycles 10a,b bind more effectively a less charged adenosine 5'-diphosphate (ADP) than adenosine 5'-triphosphate (ATP). A simple colorimetric method based on polydiacetylene vesicles decorated with 10b

• performed by the dye micellization method using pyrene and eosin Y (EY) as fluorescent and spectrophotometric probes, respectively (Table 1). The nonpolar pyrene can be incorporated into hydrophobic domains of the aggregates due to hydrophobic interactions. Pyrene insertion is measured by analyzing the

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

• host-induced protonation and thus to a fluorescence increase. The possibility to tune binding affinities and pKa values is demonstrated and it is shown that, in combination with the beneficial photophysical properties of BODIPYs, several new applications of host–dye reporter pairs can be implemented

• fluorescent dyes directly enables (bio)sensing applications through the indicator displacement principle [16][17]. Therein, the fluorescence properties of a dye are altered when encapsulated by the host, and when a competitive binder displaces the dye from the cavity, the properties of the non-encapsulated

• dye are regenerated. This principle has enabled, for example, real-time monitoring of enzymatic activity [18][19][20], the detection of membrane-transport activity [21] and membrane fusion [22], and even cellular imaging appears to be a potential future prospect [23][24]. However, most combinations of

Strong binding and fluorescence sensing of bisphosphonates by guanidinium-modified calix[5]arene

• Jie Gao,
• Zhe Zheng,
• Lin Shi,
• Si-Qi Wu,
• Hongwei Sun and
• Dong-Sheng Guo

Beilstein J. Org. Chem. 2018, 14, 1840–1845, doi:10.3762/bjoc.14.157

• , we employed fluorescein (Fl) as the reporter dye according to our previously published result [26]. Fl of high brightness is strongly encapsulated into the GC5A cavity (Ka = 5.0 × 106 M−1), accompanied with a drastic complexation-induced fluorescence quenching (Ifree/Ibound = 37). Taken together

• , these factors make the GC5A·Fl reporter pair an ideal combination for the projected IDA application. IDA was implemented to determine the binding affinities between GC5A and BPs via competitive fluorescence titrations. More importantly, the displacement of the reporter dye, accompanied with fluorescence

The phenyl vinyl ether–methanol complex: a model system for quantum chemistry benchmarking

• Dominic Bernhard,
• Fabian Dietrich,
• Mariyam Fatima,
• Cristóbal Pérez,
• Hannes C. Gottschalk,
• Axel Wuttke,
• Ricardo A. Mata,
• Martin A. Suhm,
• Melanie Schnell and
• Markus Gerhards

Beilstein J. Org. Chem. 2018, 14, 1642–1654, doi:10.3762/bjoc.14.140

• is obtained via second harmonic generation in a BBO crystal using the output of a dye laser (Cobra-Stretch and PrecisionScan, Sirah). They are pumped by the second harmonic (532 nm) of a Nd:YAG laser (SpitLight 600 and SpitLight 1000, Innolas). The IR laser radiation in the range of 3520–3750 cm−1 is

• generated by difference frequency mixing (DFM) in a LiNbO3 crystal using the fundamental (1064 nm) of a seeded Nd:YAG laser (Quanta-Ray Pro-230, Spectra-Physics) and the output of a further dye laser (PrecisionScan, Sirah), which is pumped by the second harmonic (532 nm) of the same Nd:YAG laser

Hyper-reticulated calixarene polymers: a new example of entirely synthetic nanosponge materials

• Alberto Spinella,
• Marco Russo,
• Antonella Di Vincenzo,
• Delia Chillura Martino and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2018, 14, 1498–1507, doi:10.3762/bjoc.14.127

• and shape of the guest. It is worth noting that CaNS4 shows better sequestration abilities than CaNS2 towards 6 and 8. This may be justified admitting that the presence of the aromatic linker unit favors the interaction with the aromatic dye, due to the occurrence of effective π···π interactions with

Metal-free formal synthesis of phenoxazine

• Gabriella Kervefors,
• Antonia Becker,
• Chandan Dey and
• Berit Olofsson

Beilstein J. Org. Chem. 2018, 14, 1491–1497, doi:10.3762/bjoc.14.126

• ][8], are present in a variety of dyes [9], and can be applied in chemosensors and dye-sensitized solar cells (Figure 1) [10][11][12]. N-Arylphenoxazines were recently employed as photoredox catalysts in metal-free polymerizations [13]. The first synthesis of phenoxazine dates back more than 100 years

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

• challenging tandem hairpin Py/Im polyamides which could recognize >10 base pairs with flexible linker conjugated with a fluorescent dye (either Texas Red (TR) or Cyanine 3 (Cy3)) using a Fmoc-based solid phase synthetic approach; two of the representative conjugates 23 and 24 are shown in the Figure 8 [86][87

Diels–Alder cycloadditions of N-arylpyrroles via aryne intermediates using diaryliodonium salts

• Huangguan Chen,
• Jianwei Han and
• Limin Wang

Beilstein J. Org. Chem. 2018, 14, 354–363, doi:10.3762/bjoc.14.23

• °C resulted in N-phenylnaphthalen-1-ylamine (4) in 93% yield [23], which was widely used in dye-sensitized solar cells [24], hole transport materials [25][26] and organic light-emitting diodes (OLEDs, Scheme 2a) [27]. In another similar reaction with 3am, a novel N-phenylamine derivative 5 was