End group functionalization of poly(ethylene glycol) with phenolphthalein: towards star-shaped polymers based on supramolecular interactions

• Carolin Fleischmann,
• Hendrik Wöhlk and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 2263–2269, doi:10.3762/bjoc.10.235

• absorption maximum that refers to the pink color in basic solution can be found at 554 nm in corresponding UV–vis spectra. For the phenolphthalein-containing polymer PEG-PP, a slight bathochromic effect is observed, which shifts the maximum to 561 nm. Accordingly, the decrease of the absorption at 561 nm was

• (0.05 mg/mL) a) at pH 10, b) in presence of 16.7 equiv DPE-CD at pH 12, c) in presence of 100 equiv RAMEB-CD at pH 12 (from left to right). UV–vis spectra of PEG-PP solutions containing different amounts of DPE-CD and RAMEB-CD. Three-step synthesis of azide-functionalized phenolphthalein derivative PP

Molecular recognition of AT-DNA sequences by the induced CD pattern of dibenzotetraaza[14]annulene (DBTAA)–adenine derivatives

• Marijana Radić Stojković,
• Marko Škugor,
• Łukasz Dudek,
• Jarosław Grolik,
• Julita Eilmes and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2175–2185, doi:10.3762/bjoc.10.225

• × 10−5 mol dm−3. Changes of the UV–vis spectra in response to temperature increases of up to 95 °C were negligible, and the reproducibility of the UV–vis spectra upon cooling back to 25 °C was excellent. The UV–vis spectra of new compounds (AP3am, AP5) were similar to previously studied analogues [11

• C52H51N10O4, 879.409; found, 879.407; IR-ATR (cm−1): 1249, 1286, 1412, 1446, 1483, 1560, 1588, 1643, 2863, 2935, 3057, 3317. Spectrophotometric studies The UV–vis spectra were recorded on a Varian Cary 100 Bio spectrophotometer and the CD spectra on a JASCO J815 spectrophotometer at 25 °C with appropriate 1

Scalable synthesis of 5,11-diethynylated indeno[1,2-b]fluorene-6,12-diones and exploration of their solid state packing

• Bradley D. Rose,
• Peter J. Santa Maria,
• Aaron G. Fix,
• Chris L. Vonnegut,
• Lev N. Zakharov,
• Sean R. Parkin and
• Michael M. Haley

Beilstein J. Org. Chem. 2014, 10, 2122–2130, doi:10.3762/bjoc.10.219

• the ordering of the states for fluorenone and benzophenone. To validate this experimentally, UV–vis spectra were gathered in solvents of differing polarity. We anticipated that if the S0→S1 transition corresponds to a n→π* transition, the energy separating the S0 and S1 states would be measurably

Photorelease of phosphates: Mild methods for protecting phosphate derivatives

• Sanjeewa N. Senadheera,
• Abraham L. Yousef and
• Richard S. Givens

Beilstein J. Org. Chem. 2014, 10, 2038–2054, doi:10.3762/bjoc.10.212

• [25] to give 22 (90%, Scheme 2). Deprotection of 22 with 50% acetic acid gave the α-hydroxy ketone 23 (98%) which was esterified with diethyl phosphoryl chloride in pyridine [26] to afford 2-(8-(benzyloxy)quinolin-5-yl)-2-oxoethyl diethyl phosphate (5,8-BQA DEP, 24, 30%). The UV–vis spectra of 1,4

Aryl substitution of pentacenes

• Andreas R. Waterloo,
• Anna-Chiara Sale,
• Dan Lehnherr,
• Frank Hampel and
• Rik R. Tykwinski

Beilstein J. Org. Chem. 2014, 10, 1692–1705, doi:10.3762/bjoc.10.178

• acetone. UV–vis spectroscopy Aryl pentacenes 3a–k have been studied by UV–vis absorption spectroscopy in CH2Cl2 solutions and as thin films cast from CH2Cl2 onto quartz. Solution-state UV–vis spectra show characteristic absorptions in the high-energy region with a maximum intensity absorption centered at

• (3c), although some differences in molar absorptivity are observed. Similar trends are observed within the series of pentacenes 3i, 3j, and 3k. Thus, these UV–vis spectra clearly document the lack of communication between the aryl substituent and the pentacene unit, as a result of hindered rotation

• substitution (in 3c and 3h) affords the highest degree of π-stacking amongst the derivatives examined. a) Examples of common pentacene functionalization patterns and b) unsymmetrically aryl-substituted pentacenes reported in this work. UV–vis spectra of pentacenes a) 3a–c and b) 3i–k (measured in CH2Cl2). UV

Improving the reactivity of phenylacetylene macrocycles toward topochemical polymerization by side chains modification

• Simon Rondeau-Gagné,
• Jules Roméo Néabo,
• Maxime Daigle,
• Katy Cantin and
• Jean-François Morin

Beilstein J. Org. Chem. 2014, 10, 1613–1619, doi:10.3762/bjoc.10.167

• confirm the appearance of polydiacetylene. As shown in Figure 3, the UV–vis spectra shows absorption bands at 600 and 650 nm, associated with the red and blue bands of the PDA chain, respectively [51]. To determine whether all the diyne units of PAM2 reacted during irradiation, Raman spectroscopy was

Glycosystems in nanotechnology: Gold glyconanoparticles as carrier for anti-HIV prodrugs

• Fabrizio Chiodo,
• Marco Marradi,
• Javier Calvo,
• Eloisa Yuste and
• Soledad Penadés

Beilstein J. Org. Chem. 2014, 10, 1339–1346, doi:10.3762/bjoc.10.136

• mesh copper grid (Ted Pella). The solution on the grid was left to dry in air for 14 hours at room temperature. TEM analysis was carried out in a JEOL JEM-2100F-UHR, operated at 200 kV. UV–vis spectra were carried out with a Beckman Coulter DU 800 spectrometer. The mass spectrometry detection was

Homochiral BINOL-based macrocycles with π-electron-rich, electron-withdrawing or extended spacing units as receptors for C₆₀

• Marco Caricato,
• Silvia Díez González,
• Idoia Arandia Ariño and
• Dario Pasini

Beilstein J. Org. Chem. 2014, 10, 1308–1316, doi:10.3762/bjoc.10.132

• –vis spectra. Induced CD activity associated with other absorption bands in the UV–vis spectra (particularly intense in the case of 3b and 4b, Figure S1, Supporting Information File 1) could not be detected. The intensity of the low energy component of the couplet is significantly different in the case

• in the UV–vis spectra, similarly to what was previously described for the [2 + 2] adduct 3a. In the case of macrocyles 4b and 4d, instead, an enhancement of the absorption band above 400 nm could be readily detected (Figure 4). This behavior is similar to previously reported cases in terms of band

• , the titration profiles in the insets of Figure 4 display marked differences for the calculated molar absorbivity values of the 4b@C60 and 4d@C60 complexes at saturation (2800 and 4000 M−1 cm−1, respectively). In the case of 4c, no variation in the UV–vis spectra was detected. It is likely that in this

Synthesis, characterization and DNA interaction studies of new triptycene derivatives

• Sourav Chakraborty,
• Snehasish Mondal,
• Rina Kumari,
• Sourav Bhowmick,
• Prolay Das and
• Neeladri Das

Beilstein J. Org. Chem. 2014, 10, 1290–1298, doi:10.3762/bjoc.10.130

• lanes were treated with UDG + ApeI and UDG only, respectively. UV–vis spectra showing the hyperchromic effect after addition of ctDNA (20 μM) to 5 and 6 (80 μM). UV–vis absorption spectra of (A) 2,6,14-trisubstituted triptycene derivatives 1, 3, 5 and 7 in DMSO (15 μM) at 298 K; (B) 2,7,14

Novel indolin-2-one-substituted methanofullerenes bearing long n-alkyl chains: synthesis and application in bulk-heterojunction solar cells

• Irina P. Romanova,
• Andrei V. Bogdanov,
• Inessa A. Izdelieva,
• Vasily A. Trukhanov,
• Gulnara R. Shaikhutdinova,
• Dmitry G. Yakhvarov,
• Shamil K. Latypov,
• Vladimir F. Mironov,
• Vladimir A. Dyakov,
• Ilya V. Golovnin,
• Dmitry Yu. Paraschuk and
• Oleg G. Sinyashin

Beilstein J. Org. Chem. 2014, 10, 1121–1128, doi:10.3762/bjoc.10.111

• . IR spectra were recorded using a Bruker IFS-113V instrument. UV–vis spectra in solution were recorded using a Specord UV–vis spectrophotometer. Absorption spectra in films were recorded with the help of a fiber-coupled spectrophotometer (Avantes). Mass-spectra were recorded with the use of a «Bruker

On the mechanism of photocatalytic reactions with eosin Y

• Michal Majek,
• Fabiana Filace and
• Axel Jacobi von Wangelin

Beilstein J. Org. Chem. 2014, 10, 981–989, doi:10.3762/bjoc.10.97

• employed eosin Y is converted in situ to the active species EY3 or EY4 [15][16][17][18]. Efforts to reproduce the photoredox synthesis of arylboron pinacolates in acetonitrile have so far failed in our hands when irradiating at 535 nm [21]. No product formation was observed, and the UV–vis spectra showed

• the prevalent pathway is likely dictated by the stability of the relevant catalytic intermediates. UV–vis spectra of the photoborylation reaction mixture (RM). Fluorescence spectra of the photoborylation reaction mixture (RM). Ex. = excitation wavelength. UV–vis spectrum of p-bromobenzenediazonium

• tetrafluoroborate (pBrPhN2) and bispinacolato diboron (B2pin2) in acetonitrile. UV–vis spectra of ortho-biphenyldiazonium tetrafluoroborate (biPhN2) in acetonitrile. Oxidative quenching of eosin Y with arenediazonium salts and reactions of the resultant aryl radicals. Proposed general reaction mechanism of eosin Y

Tailoring of organic dyes with oxidoreductive compounds to obtain photocyclic radical generator systems exhibiting photocatalytic behavior

• Christian Ley,
• Julien Christmann,
• Ahmad Ibrahim,
• Luciano H. Di Stefano and
• Xavier Allonas

Beilstein J. Org. Chem. 2014, 10, 936–947, doi:10.3762/bjoc.10.92

• tetrabutylammonium hexafluorophosphate (Aldrich) as supporting electrolyte. The samples were bubbled with argon for 20 minutes prior to the analysis. Ferrocene was used as standard [60]. Steady sate UV–vis spectra were obtained on a Varian Cary 4000 UV–vis double beam spectrophotometer in 1 cm path quartz UV grade

First synthesis of meso-substituted pyrrolo[1,2-a]quinoxalinoporphyrins

• Dileep Kumar Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2014, 10, 808–813, doi:10.3762/bjoc.10.76

• stretching. The structures of porphyrins (2, 3, 4a–h, 5 and 6) were further supported by mass spectral analysis, which revealed the molecular ion peak to be [M + H]+. The electronic absorption and emission data of all the synthesized compounds are presented in Table 1. The UV–vis spectra of newly prepared

• two weaker Q bands at ~553 and 594 nm. In comparison to the TPP and Zn–TPP, the UV–vis spectra of free-base porphyrins 4a–h and zinc porphyrins (5 and 6) were found to be red-sifted by 3 to 4 nm. The electronic absorption spectra of selected free-base porphyrins (4f, 4g, 4h and TPP) and zinc(II

Thermodynamically stable [4 + 2] cycloadducts of lanthanum-encapsulated endohedral metallofullerenes

• Yuta Takano,
• Yuki Nagashima,
• M. Ángeles Herranz,
• Nazario Martín and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2014, 10, 714–721, doi:10.3762/bjoc.10.65

• , 3b and 4b are concluded to be the site-isomers which were afforded by the reaction as a result of using highly reactive o-quinodimethane. The UV–vis spectra of 3b and 4b partially provide information related to their molecular structures. The spectra were firstly recorded using a diode-array detector

• containing methoxy groups is thermally less stable than the addend of 3a and 4a. The following HPLC purification afforded isolated 3b. This result suggests that 3b is more stable against heating than 4b. The UV–vis spectra of purified 4a and 3b were recorded using a spectrophotometer (UV-3150; Shimadzu Corp

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

• compounds 2b, 2h, 2i and 2n are twisted from coplanarity while the other compounds are coplanar (Figure 2). In the UV–vis spectra the similar planar structures 2a and 2c are bathochromically shifted in comparison to the twisted structure 2b. The twisting from coplanarity also results in a lower fluorescence

From porphyrin benzylphosphoramidate conjugates to the catalytic hydrogenation of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin

• Marcos C. de Souza,
• Leandro F. Pedrosa,
• Géssica S. Cazagrande,
• Vitor F. Ferreira,
• Maria G. P. M. S. Neves and
• José A. S. Cavaleiro

Beilstein J. Org. Chem. 2014, 10, 628–633, doi:10.3762/bjoc.10.54

• 1a–c showed very similar UV–vis spectra, indicating that the substitution of the electron withdrawing p-fluorine atom with the electron-donating amine phosphoramidate did not cause significant changes (see Supporting Information File 1). Attempts to selectively remove the benzyl groups of the

• ), respectively. Figure 2 represents a qualitative comparison of the UV–vis spectra of isolated TPPF20, TPCF20 and TPIF20 concerning their characteristic Q bands. The total reaction mixture from the experiments in ethanol was analyzed by 1H NMR. The ratio TPPF20:TPCF20:TPIF20 was then calculated by correlating

• , which are potentially biologically active. UV–vis spectrum (CHCl3) of the crude mixture obtained from the hydrogenation of 1a and 1b over 10% Pd/C and triethylamine. Main products from the hydrogenation of TPPF20 with 10% Pd/C. Comparative UV–vis spectra of isolated TPPF20, TPCF20 and TPIF20 in CHCl3

Tuning the interactions between electron spins in fullerene-based triad systems

• Maria A. Lebedeva,
• Thomas W. Chamberlain,
• E. Stephen Davies,
• Bradley E. Thomas,
• Martin Schröder and
• Andrei N. Khlobystov

Beilstein J. Org. Chem. 2014, 10, 332–343, doi:10.3762/bjoc.10.31

• -propenylidene]malononitrile (DCTB) as supporting matrix. UV–vis spectra were measured using a Lambda 25 Perkin Elmer Spectrometer. EPR spectra were obtained on a Bruker EMX EPR spectrometer. Cyclic voltammetry Cyclic voltammetric studies were carried out using an Autolab PGSTAT20 potentiostat, using a three

Synthesis, characterization and initial evaluation of 5-nitro-1-(trifluoromethyl)-3H-1λ³,2-benziodaoxol-3-one

• Nico Santschi,
• Roman C. Sarott,
• Elisabeth Otth,
• Reinhard Kissner and
• Antonio Togni

Beilstein J. Org. Chem. 2014, 10, 1–6, doi:10.3762/bjoc.10.1

• having an additional nitro functionality as compared to reagent 2 was successfully prepared and characterized. The resulting electronic modification was studied by analyzing carbon chemical shifts, UV–vis spectra and cyclic voltammetry. Whereas the first two methods clearly indicated the installation of

• –EI (m/z): [M + H]+ calcd for C8H3F3INNaO4, 383.8951; found, 383.8961; Anal calcd for C8H3F3INO4: C, 26.62; H, 0.84; N, 3.88; found: C, 26.67; H, 0.93; N, 4.08. Electrophilic trifluoromethylating agents 1 and 2. UV–vis spectra of reagents 2 (green) and 3 (blue) in DMSO/H2O 1:1. ORTEP representation of

Charge-transfer interaction mediated organogels from 18β-glycyrrhetinic acid appended pyrene

• Jun Hu,
• Jindan Wu,
• Qian Wang and
• Yong Ju

Beilstein J. Org. Chem. 2013, 9, 2877–2885, doi:10.3762/bjoc.9.324

• used. UV–vis spectra were measured on an Agilent Technologies 95-03 spectrometer; fluorescence spectra were measured on a Varian Cary Eclipse spectrometer; NMR spectra were recorded on Varian Mercury 300/400 spectrometers in CDCl3 and DMSO-d6; mass spectrometry was measured on a Micromass QTOF and

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

• 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

Topochemical control of the photodimerization of aromatic compounds by γ-cyclodextrin thioethers in aqueous solution

• Hai Ming Wang and
• Gerhard Wenz

Beilstein J. Org. Chem. 2013, 9, 1858–1866, doi:10.3762/bjoc.9.217

• weight cut-off of 1000 Da with demineralized water). Teflon syringe filters (0.22 μm) from Roth (Karlsruhe, Germany) were used to remove insoluble material before taking UV–vis and fluorescence measurements and the photoirradiation experiments. The UV–vis spectra of aqueous samples were taken on a Perkin

Organotellurium-mediated living radical polymerization under photoirradiation by a low-intensity light-emitting diode

• Yasuyuki Nakamura and
• Shigeru Yamago

Beilstein J. Org. Chem. 2013, 9, 1607–1612, doi:10.3762/bjoc.9.183

• . Methyl methacrylate (MMA), methyl acrylate and styrene were washed with 5% NaOH aqueous solution and were distilled over CaH2. Ethyl 2-methyltellanylisobutylate (1) and dimethyl ditelluride were prepared as reported [22]. The UV–vis spectra of 1 and dimethyl ditelluride are shown in Figure 1. Typical

Molecular assembly of amino acid interlinked, topologically symmetric, π-complementary donor–acceptor–donor triads

• M. B. Avinash,
• K. V. Sandeepa and
• T. Govindaraju

Beilstein J. Org. Chem. 2013, 9, 1565–1571, doi:10.3762/bjoc.9.178

• ). Interestingly, in the case of 2, (both in aqueous DMSO as well as in aqueous NMP) a new weak emission band at ~460 nm was observed, which was attributed to the excimer of pyrene (see Supporting Information File 1). In addition, UV–vis spectra clearly show a new broad absorption band in the range of 450 nm to

• DMSO for various percentages of water in DMSO. Excitation at 345 nm. For comparison fluorescence emission spectra of pyrenemethylamine hydrochloride is shown (black trace, pyrene) in (b). (c) UV–vis spectra of 1 mM solutions of 1, 2 and 3 in 40% aqueous DMSO/NMP show the charge-transfer bands. The

Structures of the reaction products of the AZADO radical with TCNQF₄ or thiourea

• Hideto Suzuki,
• Yuta Kawahara,
• Hiroki Akutsu,
• Jun-ichi Yamada and
• Shin’ichi Nakatsuji

Beilstein J. Org. Chem. 2013, 9, 1487–1491, doi:10.3762/bjoc.9.169

• ). Nevertheless, it still has a weak acceptor ability as anticipated from the values. The UV–vis spectra of AZADO (2), TCNQF4 (3) and the adduct 5 in acetonitrile solution are shown in Figure 3. Only very weak and broad absorptions could be discriminated for AZADO radical (2) at around 250 nm and at 450 nm and

• obtained by X-ray analysis. UV–vis spectra of 2 (red line), 3 (blue line) and 5 (green line). Crystal structure of the inclusion compound 6 obtained by X-ray analysis. Difference of the reaction products from TEMPO (1) and AZADO (2) with TCNQF4 (3). A plausible mechanism of the reaction of AZADO (2) with

Simple and rapid hydrogenation of p-nitrophenol with aqueous formic acid in catalytic flow reactors

• Rahat Javaid,
• Shin-ichiro Kawasaki,
• Akira Suzuki and
• Toshishige M. Suzuki

Beilstein J. Org. Chem. 2013, 9, 1156–1163, doi:10.3762/bjoc.9.129

• testing for continuous hydrogenation of 0.01 M p-nitrophenol with 0.05 M formic acid in the porous PdO-coated reactor. Residence time: 14.7 s. Hydrogenation of p-nitrophenol with formic acid. Supporting Information The Supporting Information features the isosbestic points in the UV–vis spectra of the