Synthesis and photophysical characteristics of polyfluorene polyrotaxanes

• Aurica Farcas,
• Giulia Tregnago,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert and
• Franco Cacialli

Beilstein J. Org. Chem. 2015, 11, 2677–2688, doi:10.3762/bjoc.11.288

• lifetime τ = 0.7 ns and 0.8 ns, whereas the 3·TM-γCD polyrotaxane shows a bi-exponential decay consisting of a main component (with a weight of 98% of the total luminescence) with a relatively short decay constant of τ1 = 0.7 ns and a minor component with a longer lifetime of τ2 = 5.4 ns (2%). The

• weights of 98 and 2%, respectively. The longer τ for the 3·TM-γCD polyrotaxane is consistent with “interchain states”. While these do not dominate the luminescence of the materials (the longer lifetime only accounts for 2% of the total PL weight), they are plausible, considered the significantly bigger

2-Hetaryl-1,3-tropolones based on five-membered nitrogen heterocycles: synthesis, structure and properties

• Yury A. Sayapin,
• Inna O. Tupaeva,
• Alexandra A. Kolodina,
• Eugeny A. Gusakov,
• Vitaly N. Komissarov,
• Igor V. Dorogan,
• Nadezhda I. Makarova,
• Anatoly V. Metelitsa,
• Valery V. Tkachev,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2015, 11, 2179–2188, doi:10.3762/bjoc.11.236

• manifested in the batochromic (Δλ = 15–19 nm) shift of the longest wavelength absorption band as compared with the parent 2-(2-hydroxyphenyl)benzoxazole (cyclohexane, λmax = 321, 334 nm [35]). The excitation spectra of ASS-luminescence correspond to the absorption spectra of the hydroxy form of compounds 11a

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

• macrocycles. These molecules show excellent chiroptical properties such as high fluorescence quantum efficiency and a large circularly polarized luminescence dissymmetry factor. Cyclophanes are carbon-rich materials containing extensive alkyne moieties with a persistent molecular architecture. Orita and co

Properties of PTFE tape as a semipermeable membrane in fluorous reactions

• Brendon A. Parsons,
• Olivia Lin Smith,
• Myeong Chae and
• Veljko Dragojlovic

Beilstein J. Org. Chem. 2015, 11, 980–993, doi:10.3762/bjoc.11.110

• reaction was directional. Only the oxalate–rubrene solution exhibited luminescence during the reaction, regardless of whether it was in the delivery tube or the vial (Figure 11). The peroxide solution remained dark. The reactions with the aqueous peroxide solution proceeded with no change in the column

Synthesis and chemosensing properties of cinnoline-containing poly(arylene ethynylene)s

• Natalia A. Danilkina,
• Petr S. Vlasov,
• Semen M. Vodianik,
• Andrey A. Kruchinin,
• Yuri G. Vlasov and
• Irina A. Balova

Beilstein J. Org. Chem. 2015, 11, 373–384, doi:10.3762/bjoc.11.43

• Optical sensors provide an efficient and sensitive approach for the rapid detection and identification of a wide range of chemical substrates by measuring the changes of optical properties such as absorbance, reflectance, luminescence, or fluorescence [1]. Among them a type of sensors based on conjugated

Conjugates of methylated cyclodextrin derivatives and hydroxyethyl starch (HES): Synthesis, cytotoxicity and inclusion of anaesthetic actives

• Lisa Markenstein,
• Antje Appelt-Menzel,
• Marco Metzger and
• Gerhard Wenz

Beilstein J. Org. Chem. 2014, 10, 3087–3096, doi:10.3762/bjoc.10.325

• generation of a luminescent signal proportional to the amount of ATP present, which is directly proportional to the number of cells in culture. The luminescence signal was measured in a plate reader (infinite M200, TECAN, Männedorf, Swizerland). 5a and DIMEB were each solved in standard basal medium (MEM) or

• luminescence was measured after 2 min of shaking and 10 min incubation at room temperature in the TECAN plate reader. All results presented are based on at least three independent biological tests. Statistical significance was determined by analysis of variance and p < 0.05. Materials: Hydroxyethyl starch (HES

Synthesis and properties of novel star-shaped oligofluorene conjugated systems with BODIPY cores

• Clara Orofino-Pena,
• Diego Cortizo-Lacalle,
• Joseph Cameron,
• Muhammad T. Sajjad,
• Pavlos P. Manousiadis,
• Neil J. Findlay,
• Alexander L. Kanibolotsky,
• Dimali Amarasinghe,
• Peter J. Skabara,
• Tell Tuttle,
• Graham A. Turnbull and
• Ifor D. W. Samuel

Beilstein J. Org. Chem. 2014, 10, 2704–2714, doi:10.3762/bjoc.10.285

• ,4a-diaza-s-indacene unit has attracted much attention due to the properties it imparts to the compounds that contain it, such as efficient luminescence, high absorptivity, good photostability and solubility in common solvents [1][2][3][4]. Due to these properties, BODIPY-containing conjugated systems

• lowers the luminescence efficiency of the material. Due to this aggregation and a low Stokes shift, BODIPY dyes with efficient emission in the solid state are still rare [16]. One of the strategies to suppress the aggregation of π-functional emissive units is to incorporate them into star-shaped

A small azide-modified thiazole-based reporter molecule for fluorescence and mass spectrometric detection

• Stefanie Wolfram,
• Hendryk Würfel,
• Stefanie H. Habenicht,
• Christine Lembke,
• Phillipp Richter,
• Eckhard Birckner,
• Rainer Beckert and
• Georg Pohnert

Beilstein J. Org. Chem. 2014, 10, 2470–2479, doi:10.3762/bjoc.10.258

• samples in aqueous solution. Ideally a pH-independent fluorescence should guarantee for unbiased detection in tissues or under variable analytical conditions. In the light of our detailed knowledge of luminescence properties of pyridylthiazoles we considered this compound class to be ideally suited for

• , USA) in combination with a Luminescence Spectrophotometer LS 50 (Perkin Elmer, Waltham, MA, USA). For DNS (8) and NBD (9) emission maxima were obtained with a FP-6500 (Jasco, Tokyo, Japan) spectrofluorimeter. LC–ESIMS and UV–vis detection For LC–MS measurements we used an Acquity™ Ultraperformance LC

The effect of permodified cyclodextrins encapsulation on the photophysical properties of a polyfluorene with randomly distributed electron-donor and rotaxane electron-acceptor units

• Aurica Farcas,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert,
• Flavian Farcas,
• Iuliana Stoica and
• Anton Airinei

Beilstein J. Org. Chem. 2014, 10, 2145–2156, doi:10.3762/bjoc.10.222

• “insulation” of the individual molecular wires. Moreover, recently reported results have shown improvements of the thermal stability, solubility, luminescence and surface characteristics of polyrotaxanes compared to those of non-rotaxane counterparts [8][13][19][20][21][22][23][24][25]. This approach has also

Synthesis of new, highly luminescent bis(2,2’-bithiophen-5-yl) substituted 1,3,4-oxadiazole, 1,3,4-thiadiazole and 1,2,4-triazole

• Anastasia S. Kostyuchenko,
• Vyacheslav L.Yurpalov,
• Aleksandra Kurowska,
• Wojciech Domagala,
• Adam Pron and
• Alexander S. Fisyuk

Beilstein J. Org. Chem. 2014, 10, 1596–1602, doi:10.3762/bjoc.10.165

• functionalised oligothiophenes, coupled to other heteroaromatic cores. Keywords: bithiophene; donor–acceptor; luminescence; 1,3,4-oxadiazole; 1,3,4-thiadiazole; 4H-1,2,4-triazole; Introduction In the past two decades oligo- and polythiophenes gained a significant research interest due to their wide application

• ][12][13][14][15], oxadiazole [14][15][16][17] or tetrazine units [13][18][19][20] have been reported. Moreover, luminescence properties of these derivatives are superior to those of the corresponding penta-ring oligothiophenes. For example, the central heterocycle ring replacement in substituted

Pyrene-modified PNAs: Stacking interactions and selective excimer emission in PNA₂DNA triplexes

• Alex Manicardi,
• Lucia Guidi,
• Alice Ghidini and
• Roberto Corradini

Beilstein J. Org. Chem. 2014, 10, 1495–1503, doi:10.3762/bjoc.10.154

• maximum of the first derivative of the melting curves. Fluorescence measurements. Fluorescence spectra were recorded on a Perkin Elmer LS55 luminescence spectrometer equipped with a LAUDA ECOline RE104 temperature control system, exciting at 347 nm (slit: 5.0 nm), scanning from 370 nm to 550 nm, a scan

Palladium-catalysed cross-coupling reaction of ultra-stabilised 2-aryl-1,3-dihydro-1H-benzo[d]1,3,2-diazaborole compounds with aryl bromides: A direct protocol for the preparation of unsymmetrical biaryls

• Siphamandla Sithebe and
• Ross S. Robinson

Beilstein J. Org. Chem. 2014, 10, 1107–1113, doi:10.3762/bjoc.10.109

• π-conjugated organic molecules containing a three-coordinate boron moiety such as trimesitylborane (4), arylalkynyldimesitylborane 5 and 2-aryl-1,3-diethyl-1H-benzo[d]1,3,2-diazaborole 6 (Figure 2) are well known and have received considerable attention due to their interesting luminescence

The Ugi four-component reaction as a concise modular synthetic tool for photo-induced electron transfer donor-anthraquinone dyads

• Sarah Bay,
• Gamall Makhloufi,
• Christoph Janiak and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2014, 10, 1006–1016, doi:10.3762/bjoc.10.100

• . These novel donor–acceptor dyads are electronically decoupled in the electronic ground state according to UV–vis spectroscopy and cyclic voltammetry. However, in the excited state the inherent donor luminescence is efficiently quenched. Previously performed femtosecond spectroscopic measurements account

Metal and metal-free photocatalysts: mechanistic approach and application as photoinitiators of photopolymerization

• Jacques Lalevée,
• Sofia Telitel,
• Pu Xiao,
• Marc Lepeltier,
• Frédéric Dumur,
• Fabrice Morlet-Savary,
• Didier Gigmes and
• Jean-Pierre Fouassier

Beilstein J. Org. Chem. 2014, 10, 863–876, doi:10.3762/bjoc.10.83

• -trapping, laser flash photolysis, steady state photolysis, cyclic voltammetry and luminescence experiments. Keywords: LEDs; photoinitiators; photopolymerization; photoredox catalysis; Introduction Photoredox catalysis is now well-known and largely used in organic synthesis, especially in the development

• /luminescence experiments (Figure 7B). From these data, a favorable 3Ir(piq)2(tmd)/Ph2I+ oxidation process can be expected, i.e., the free energy change ΔG for the corresponding electron transfer is negative (ΔG = −1.2 eV as calculated from the classical Rehm–Weller ΔG = Eox – Ered – ET + C where Eox, Ered, ET

• polymerized through a photoredox catalysis approach. The new proposed PIC (Ir(piq)2(tmd)). UV–visible light absorption spectra for Ir(piq)2(tmd) (2) and Ir(ppy)3 (1); solvent: acetonitrile. (A) cyclic voltamogramm for Ir(piq)2(tmd) in acetonitrile; (B) absorption (a) and luminescence (b) spectra for Ir(piq)2

Rapid pseudo five-component synthesis of intensively blue luminescent 2,5-di(hetero)arylfurans via a Sonogashira–Glaser cyclization sequence

• Fabian Klukas,
• Alexander Grunwald,
• Franziska Menschel and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2014, 10, 672–679, doi:10.3762/bjoc.10.60

• interesting due to their bright blue luminescence with remarkably high quantum yields. The electronic structure of the title compounds is additionally studied with DFT computations. Keywords: C–C coupling; copper; DFT; fluorescence; furans; mircowave-assisted synthesis; multicomponent reactions; palladium

• 2,5-diphenylfuran (2a, Table 1) starting from 1,4-diphenylbutadiyne (1a) as a substrate. Just upon eyesight a remarkable luminescence of 2a caught our attention and we were encouraged to perform photophysical studies with these products as well (vide infra). In a set of experiments the reaction times

• in a one-pot fashion, which opens a ready access to biologically active furan derivatives. In addition the investigation of the photophysical properties of these compounds reveals an intense blue luminescence in solution approaching unity for the fluorescence quantum yield Φf of distinct derivatives

One-pot three-component synthesis and photophysical characteristics of novel triene merocyanines

• Christian Muschelknautz,
• Robin Visse,
• Jan Nordmann and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2014, 10, 599–612, doi:10.3762/bjoc.10.51

• recorded in dichloromethane solution and of thin films prepared by dropcasting of concentrated dichloromethane solutions on glass-probe cuvettes (Table 4). For the powders and films of the merocyanines 8 intense deep-red luminescence was detected upon eyesight. The emission spectra of the films of 8 were

• responsible for the intense longest-wavelength absorption band upon optical excitation (Figure 4). In contrast to the deep-red luminescence of both amorphous films and dyes in the solid state with sharp bands between 644 and 665 nm (Figure 5), the emission in solution is completely quenched. As already

• formation of the corresponding 4-(3-methylbenzo[d]thiazol-2(3H)-ylidene)but-2-en-1-ylideneindolone. 4-(1,3,3-Trimethylindolin-2-ylidene)but-2-en-1-ylideneindolones are also the exclusive products for N-tosylanilides as starting materials. As a result of aggregation-induced luminescence, 1-styryleth-2

Physalin H from Solanum nigrum as an Hh signaling inhibitor blocks GLI1–DNA-complex formation

• Midori A. Arai,
• Kyoko Uchida,
• Samir K. Sadhu,
• Firoj Ahmed and
• Masami Ishibashi

Beilstein J. Org. Chem. 2014, 10, 134–140, doi:10.3762/bjoc.10.10

• previously described method [18]. Detection of the Hh inhibitory activity was based on the decrease in the luminescence value due to reduced luciferase expression by GLI1 compared to that of the control (DMSO). In addition we always checked the cytotoxicity of the compounds against the assay cells, because a

Synthesis, characterization and luminescence studies of gold(I)–NHC amide complexes

• Adrián Gómez-Suárez,
• David J. Nelson,
• David G. Thompson,
• David B. Cordes,
• Duncan Graham,
• Alexandra M. Z. Slawin and
• Steven P. Nolan

Beilstein J. Org. Chem. 2013, 9, 2216–2223, doi:10.3762/bjoc.9.260

• = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) with a series of commercially available (hetero)aromatic amines leads to the synthesis of several [Au(NRR’)(IPr)] complexes in good yields and with water as the sole byproduct. Interestingly, these complexes present luminescence properties. UV–vis and

• species as luminescent materials. We began our luminescence studies by recording the UV–vis spectra of the aforementioned gold–amide complexes using a dilute (ca. 0.2 mmol/L) CH2Cl2 solution. The wavelengths of the absorption maxima on the UV–vis spectra were in the range of 250–350 nm for most complexes

• . Lifetimes for all luminescence measurements were ≤1 μs (at the limit of the apparatus), suggesting that the luminescence was due to fluorescence, rather than phosphorescence. The wavelengths of emission maxima spans the range 390 to 516 nm, demonstrating that by selecting the appropriate amine ligand the

Studies on the photodegradation of red, green and blue phosphorescent OLED emitters

• Susanna Schmidbauer,
• Andreas Hohenleutner and
• Burkhard König

Beilstein J. Org. Chem. 2013, 9, 2088–2096, doi:10.3762/bjoc.9.245

• irradiation times was determined by HPLC analysis, for the solid samples by measuring the luminescence intensities of the samples. The majority of the experiments was performed at least twice and was reproducible within an estimated error of <10%. The degradation curves were generated by using the average

• beginning of the experiment (Figure 3). However, after 15–20 min of irradiation, the luminance changes decrease significantly. A possible explanation is the formation of degradation products which are still capable of phosphorescent emission, albeit at lower luminescence quantum efficiencies. This rational

Synthesis, photophysical and electrochemical characterization of terpyridine-functionalized dendritic oligothiophenes and their Ru(II) complexes

• Amaresh Mishra,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2013, 9, 866–876, doi:10.3762/bjoc.9.100

• ligands, 2,2':6',2"-terpyridine (tpy) has been used extensively, despite the low luminescence displayed by these complexes, due to the interesting geometry of the tpy ligand, which allows axial type arrangement of the substituents placed on the 4'-position of the coordinated tpy. Among them, ligands of

• increasing generation. Therefore, UV–vis absorption and luminescence spectra of ligands 8, 9 and metallodendrimers 1, 2 were measured and analyzed (Table 1). Absorption spectra of ligands 8, 9 and complexes 1, 2 in air-equilibrated acetonitrile at 293 K are shown in Figure 1a and summarized in Table 1

• + complex (Δλem = 64 and 126 nm, respectively, Table 1) [48], indicating that the 3MLCT luminescence energy levels in these complexes undergo a stabilization with increasing size of the thienylene-ethynylene units [18]. Beley et al. reported a similar red-shift of the 3MLCT emission band for the [Ru(tpy-th

Superstructures of fluorescent cyclodextrin via click-reaction

• Arkadius Maciollek,
• Helmut Ritter and
• Rainer Beckert

Beilstein J. Org. Chem. 2013, 9, 827–831, doi:10.3762/bjoc.9.94

• Elmer LS55 luminescence spectrometer. AF4 measurements in ultrapure water were carried out on a combined system comprising the following elements: refractive index detector Optilabrex (Wyatt Technologies, laser wavelength 658 nm), three angle light scattering detector miniDawn TREOS (Wyatt Technologies

Spin state switching in iron coordination compounds

• Philipp Gütlich,
• Ana B. Gaspar and
• Yann Garcia

Beilstein J. Org. Chem. 2013, 9, 342–391, doi:10.3762/bjoc.9.39

Synthesis and characterization of low-molecular-weight π-conjugated polymers covered by persilylated β-cyclodextrin

• Aurica Farcas,
• Ana-Maria Resmerita,
• Andreea Stefanache,
• Mihaela Balan and
• Valeria Harabagiu

Beilstein J. Org. Chem. 2012, 8, 1505–1514, doi:10.3762/bjoc.8.170

• particular have been the focus of much research as encouraging candidates for organic light-emitting diodes (OLEDs) due to their pure blue luminescence and high efficiency [5][6][7][8][9][10]. The application of PFs and PDOF conjugated polymers is limited by unwanted side effects, such as aggregation and a

• the sample in a temperature range 25–800 °C. Absorption spectra were measured on a Specord 200 spectrophotometer in CHCl3 solution and on thin films. Fluorescence spectra were obtained with a Perkin Elmer LS55 luminescence spectrophotometer. The surface images were obtained with a Solver PRO-M

A simple and efficient dual optical signaling chemodosimeter for toxic Hg(II)

• Sabir H. Mashraqui,
• Sapna A. Tripathi,
• Sushil S. Ghorpade and
• Smita R. Britto

Beilstein J. Org. Chem. 2012, 8, 1352–1357, doi:10.3762/bjoc.8.155

• ratiometric or switch-on responses even for the paramagnetic metal ions [17][18][19]. The first luminescence chemodosimeter for Hg2+ was developed by Czarnik et al. and was based on the Hg2+-mediated desulfurization of anthracene-thioamide chromophore [20][21]. Following this pioneering report, several other

Synthesis of new pyrrole–pyridine-based ligands using an in situ Suzuki coupling method

• Matthias Böttger,
• Björn Wiegmann,
• Steffen Schaumburg,
• Peter G. Jones,
• Wolfgang Kowalsky and
• Hans-Hermann Johannes

Beilstein J. Org. Chem. 2012, 8, 1037–1047, doi:10.3762/bjoc.8.116

• nine and thereby saturated. Our interest in this type of complex is driven by its potential analytical application for luminescence degradation measurements on photocatalytic surfaces [8]. Currently, β-diketonate complexes are in use for this analysis, but homoleptic complexes may be advantageous in