Polysubstituted ferrocenes as tunable redox mediators

• Sven D. Waniek,
• Jan Klett,
• Christoph Förster and
• Katja Heinze

Beilstein J. Org. Chem. 2018, 14, 1004–1015, doi:10.3762/bjoc.14.86

• IR-SEC experiments, the esters 1–4 were also probed by UV–vis-SEC investigations. The UV–vis spectra of 1–4 recorded in dichloromethane show the ferrocene ligand field absorption band at λmax = 444, 449, 455 and 457 nm, which is typically around λmax ≈ 440–490 nm [66][70][79][80] (Figure 5a). The

• Information File 1). Probably, precipitation of the poorly soluble tetraester 4+ could be responsible for this effect, as already suggested for the IR-SEC experiments of 4/4+. On the other hand, isosbestic points are observed in the UV–vis spectra upon re-reduction of 4+ to 4 (Figure S31, Supporting

• dependency of the energy on the number n of methoxycarbonyl substituents can be found than for the ligand field band of the ferrocenes 1–4 (Figure 6b). The lowest energy band (band I) in the UV–vis spectra of 1+–4+ is assigned to ligand-to-metal charge transfer (LMCT) transitions [79][81][82][83]. The bands

An air-stable bisboron complex: a practical bidentate Lewis acid catalyst

• Longcheng Hong,
• Sebastian Ahles,
• Andreas H. Heindl,
• Gastelle Tiétcha,
• Andrey Petrov,
• Zhenpin Lu,
• Christian Logemann and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2018, 14, 618–625, doi:10.3762/bjoc.14.48

• experimental procedures, copies of 1H and 13C NMR spectra, UV–vis spectra as well as the X-ray crystallography. Supporting Information File 32: CIF of bisborane complex B. Acknowledgements Funding by the BMEL (Federal Ministry of Food and Agriculture) within the project FOREST (22403116) and by the CMBlu AG

Polarization spectroscopy methods in the determination of interactions of small molecules with nucleic acids – tutorial

• Tamara Šmidlehner,
• Ivo Piantanida and
• Gennaro Pescitelli

Beilstein J. Org. Chem. 2018, 14, 84–105, doi:10.3762/bjoc.14.5

• mechanism between the various π→π* transitions of regularly arranged chromophores [14] (Figure 3, top). Chiroptical properties and ECD spectra of particular DNA or RNA sequences are therefore strongly dependent on the polynucleotide secondary structure [15], at variance to the common UV–vis spectra of the

• richer in bands than a typical ECD spectrum (just like IR spectra vs UV–vis spectra) [1][4][36]. Nowadays, density functional theory (DFT) allows a calculation of the VCD spectrum of a chiral molecule, which then can be compared with the measured VCD spectrum and by this the absolute configuration (AC

Halogen-containing thiazole orange analogues – new fluorogenic DNA stains

• Aleksey A. Vasilev,
• Meglena I. Kandinska,
• Stanimir S. Stoyanov,
• Stanislava B. Yordanova,
• David Sucunza,
• Juan J. Vaquero,
• Obis D. Castaño,
• Stanislav Baluschev and
• Silvia E. Angelova

Beilstein J. Org. Chem. 2017, 13, 2902–2914, doi:10.3762/bjoc.13.283

• . Interactions of the new derivatives of TO with dsDNA have been investigated by absorption and fluorescence spectroscopy. The longest wavelength absorption bands in the UV–vis spectra of the target compounds are in the range of 509–519 nm and these are characterized by high molar absorptivities (63000–91480

• , 3a, and 3b were commercially available and were used as supplied. Melting points were determined on a Kofler apparatus and are uncorrected. NMR spectra were obtained on a Bruker Avance III 500 DRX 600 MHz spectrometer in DMSO-d6. UV–vis spectra were measured on a Unicam 530 UV–vis spectrophotometer

Asymmetric synthesis of propargylamines as amino acid surrogates in peptidomimetics

• Matthias Wünsch,
• David Schröder,
• Tanja Fröhr,
• Lisa Teichmann,
• Sebastian Hedwig,
• Nils Janson,
• Clara Belu,
• Jasmin Simon,
• Shari Heidemeyer,
• Philipp Holtkamp,
• Jens Rudlof,
• Lennard Klemme,
• Alessa Hinzmann,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2017, 13, 2428–2441, doi:10.3762/bjoc.13.240

• (conversion of 11i to 12i). Or LiOH (3 equiv), MeOH/H2O (2:1), 0 °C, 30 min. B) UV–vis spectra of propargylamines 11 and α,β-unsaturated imines 12. C) X-ray crystal structure analysis of propargylamine 11i and α,β-unsaturated imine 12i. Preparation of N-sulfinyl propargylamines 7 with aliphatic side chains.a

Synthesis and application of trifluoroethoxy-substituted phthalocyanines and subphthalocyanines

• Satoru Mori and
• Norio Shibata

Beilstein J. Org. Chem. 2017, 13, 2273–2296, doi:10.3762/bjoc.13.224

• mononuclear phthalocyanine does not show any aggregation effect [74]. The aggregation behavior can be estimated from the UV–vis spectra. Phthalocyanine, which is free from aggregation, exhibits a sharp Q band, but the Q band of aggregated phthalocyanine is broadened and shifts to the shorter wavelength region

• and H-subPc heterodimer. Since the UV–vis spectra of a heterodimer are the sum of the absorption spectra of the respective units, it is suggested that each unit has an independent π-conjugate system. On the other hand, the fluorescence quantum yield decreased as a whole and the fluorescence derived

• of axial ligand substituted subphthalocyanine hybrid dyes. Energy transfer between subphthalocyanine units. Structure of phthalocyanine and subphthalocyanine benzene-fused homodimers. X-ray crystallography of Pc-subPc (left) and UV–vis spectra of benzene-fused dimers. Synthesis of trifluoroethoxy

Complexation of molecular clips containing fragments of diphenylglycoluril and benzocrown ethers with paraquat and its derivatives

• Leonid S. Kikot',
• Catherine Yu. Kulygina,
• Alexander Yu. Lyapunov,
• Svetlana V. Shishkina,
• Roman I. Zubatyuk,
• Tatiana Yu. Bogaschenko and
• Tatiana I. Kirichenko

Beilstein J. Org. Chem. 2017, 13, 2056–2067, doi:10.3762/bjoc.13.203

• analysis of UV–vis spectra could also provide qualitative information on the formation of inclusion complexes in solution. The addition of guests 7–10 to a solution of clips 1–5 turns the colourless solution to yellow, and a new wide absorption band (370–560 nm) appears. The new band was assigned to a

• , Supporting Information File 1). Typical changes in the UV–vis spectra during the titration of clip 2 with paraquat (7) are presented in Figure 4. The data obtained for molecular clips 1–3 are best described by titration curves corresponding to 1:1, and for clips 4 and 5 – to 1:1 and 1:2 complexes. Stability

• , v/v) of (a) free host 3, (b) 3 and 1.0 equiv of 7, and (c) free guest 7. The changes observed in the UV–vis spectra during the titration of clip 2 with paraquat (7) in acetonitrile at 20 °C. The labels near each plot correspond to the equivalents of paraquat (7) added. Stability constant dependence

β-Cyclodextrin- and adamantyl-substituted poly(acrylate) self-assembling aqueous networks designed for controlled complexation and release of small molecules

• Liang Yan,
• Duc-Truc Pham,
• Philip Clements,
• Stephen F. Lincoln,
• Jie Wang,
• Xuhong Guo and
• Christopher J. Easton

Beilstein J. Org. Chem. 2017, 13, 1879–1892, doi:10.3762/bjoc.13.183

• spectroscopy The UV–vis spectra were recorded with a Cary-Varian 5000 UV–vis spectrophotometer using 1 cm path length matched quartz cells. All UV–vis titrations were performed in aqueous Na2HPO4/KH2PO4 buffer at pH 7.0 and I = 0.10 mol dm−3 at 298.2 K. For the β-CD/dye titrations, 50 mm3 aliquots of a β-CD

Direct catalytic arylation of heteroarenes with meso-bromophenyl-substituted porphyrins

• Alexei N. Kiselev,
• Olga K. Grigorova,
• Alexei D. Averin,
• Sergei A. Syrbu,
• Oskar I. Koifman and
• Irina P. Beletskaya

Beilstein J. Org. Chem. 2017, 13, 1524–1532, doi:10.3762/bjoc.13.152

• tatraarylated derivatives. The investigation of the UV–vis spectra of the arylated monophenylporphyrins 3–9 disclosed that they possess almost identical absorption maxima but somewhat differ in extinction values primarily due to the different sharpness of the bands (Table 4). The Soret band at 406 nm is

• bromophenylporphyrinate. The UV–vis spectra of diphenylporphyrins 13–15 (Table 4) possess absorption bands in the same region as their monophenyl analogues 3–9, but all maxima are slightly red-shifted. It fully corresponds with the absorption bands of the bis(4-bromophenyl)porphyrin 11 (λmax 575 (lgε 3.16), 540 (lgε 3.38

Switchable highly regioselective synthesis of 3,4-dihydroquinoxalin-2(1H)ones from o-phenylenediamines and aroylpyruvates

• Juraj Dobiaš,
• Marek Ondruš,
• Gabriela Addová and
• Andrej Boháč

Beilstein J. Org. Chem. 2017, 13, 1350–1360, doi:10.3762/bjoc.13.132

• )-one system. The keto–enamine arrangement in 3 is capable of specific binding of Cu(II) ions like in 4, which was proved by red shifts in the UV–vis spectra [6][7][8]. The pseudo ring can also accommodate BF2 moiety, yielding compounds like 5 with interesting fluorescent properties [9][10]. Compounds 3

Molecular-level architectural design using benzothiadiazole-based polymers for photovoltaic applications

• Vinila N. Viswanathan,
• Arun D. Rao,
• Upendra K. Pandey,
• Arul Varman Kesavan and
• Praveen C. Ramamurthy

Beilstein J. Org. Chem. 2017, 13, 863–873, doi:10.3762/bjoc.13.87

• . The UV–vis spectra of annealed films of the polymers at 130 °C show an apparent red shift in the onset absorption because of an increased aggregation of the polymer chains upon heating. The optical band gaps of P1, P2, and P3 were calculated from the onset of the absorption as 1.95 eV, 1.93 eV and

Derivatives of the triaminoguanidinium ion, 5. Acylation of triaminoguanidines leading to symmetrical tris(acylamino)guanidines and mesoionic 1,2,4-triazolium-3-aminides

• Jan Szabo,
• Julian Greiner and
• Gerhard Maas

Beilstein J. Org. Chem. 2017, 13, 579–588, doi:10.3762/bjoc.13.57

• , the δ(C-5) value in 7d corresponds to the deshielding α-effect of a methyl group, if one takes the δ-value of the unsubstituted C-5 carbon nucleus in II as a reference. The UV–vis spectra of 7a–d are presented in Figure 5. One notes an increasingly bathochromic shift of the long-wavelength absorption

• , N4H···N11 2.061(1) Å; <(N4–H···N11) 168.7(2)°. UV–vis spectra of 7a–d in chloroform (c = 0.04 mmol L−1); λmax [nm] (ε [L mol−1 cm−1]): 7a: 350 (4710); 7b: 350 (5080); 7c: 430 (3510); 7d: 300 (2670). Reactions of aminoguanidines with carboxylic acids and acid chlorides. The structural formulae shown

Pd- and Cu-catalyzed approaches in the syntheses of new cholane aminoanthraquinone pincer-like ligands

• Nikolay V. Lukashev,
• Gennadii A. Grabovyi,
• Dmitry A. Erzunov,
• Alexey V. Kazantsev,
• Gennadij V. Latyshev,
• Alexei D. Averin and
• Irina P. Beletskaya.

Beilstein J. Org. Chem. 2017, 13, 564–570, doi:10.3762/bjoc.13.55

• jellyfish resembling receptors (b) [11][16]. UV–vis spectra of 5c (50 μM solution in MeCN) before and after the addition of 5 equiv of metal perchlorates. Example of Pd-catalyzed amination for modification of bile acid derivatives. Synthesis of 24-aminocholanols. Synthesis of 24-arylaminocholanols by Cu

Spectral and DFT studies of anion bound organic receptors: Time dependent studies and logic gate applications

• Srikala Pangannaya,
• Neethu Padinchare Purayil,
• Shweta Dabhi,
• Venu Mankad,
• Prafulla K. Jha,
• Satyam Shinde and
• Darshak R. Trivedi

Beilstein J. Org. Chem. 2017, 13, 222–238, doi:10.3762/bjoc.13.25

• corresponding UV–vis spectra are shown in Supporting Information File 1, Figures S19 and S20. There was no remarkable colorimetric response in the presence of the other cations tested in the current study. In case of receptor R2 no color change was observed in the presence of the cations implying its role as an

Efficient access to β-vinylporphyrin derivatives via palladium cross coupling of β-bromoporphyrins with N-tosylhydrazones

• Vinicius R. Campos,
• Ana T. P. C. Gomes,
• Anna C. Cunha,
• Maria da Graça P. M. S. Neves,
• Vitor F. Ferreira and
• José A. S. Cavaleiro

Beilstein J. Org. Chem. 2017, 13, 195–202, doi:10.3762/bjoc.13.22

• -brominated porphyrin 1 and N-tosylhydrazones 2a–c. Results obtained in the palladium-catalyzed cross-coupling reactions between β-brominated porphyrin 1 with N-tosylhydrazones 2a–c. Supporting Information Supporting Information File 46: Copies of NMR, HRMS(ESI) and UV–vis spectra of the new derivatives

• ) using CHCl3 as solvent. For the reactions under MW irradiation a CEM Microwave Synthesis System Discover SP was used, under constant magnetic stirring (controlled by the microwave equipment) by employing an irradiation power of 200 W till the reaction temperature (120 °C) was achieved. The UV–vis

• spectra were recorded on an UV-2501 PC Shimadzu spectrophotometer using CHCl3 as solvent. Flash chromatography was carried out using silica gel (230–400 mesh) and preparative thin-layer chromatography was carried out on 20 × 20 cm glass plates coated with silica gel (1 mm thick). The reactions were

3D printed fluidics with embedded analytic functionality for automated reaction optimisation

• Andrew J. Capel,
• Andrew Wright,
• Matthew J. Harding,
• George W. Weaver,
• Yuqi Li,
• Russell A. Harris,
• Steve Edmondson,
• Ruth D. Goodridge and
• Steven D. R. Christie

Beilstein J. Org. Chem. 2017, 13, 111–119, doi:10.3762/bjoc.13.14

• selected because it would run smoothly at room temperature, and a mild solvent mixture such as methanol and water (MeOH/water) could be used with the less solvent-compatible parts. Differences between the UV–vis spectra of the starting material and the product can be used to follow the reaction

Enzymatic synthesis and phosphorolysis of 4(2)-thioxo- and 6(5)-azapyrimidine nucleosides by E. coli nucleoside phosphorylases

• Vladimir A. Stepchenko,
• Anatoly I. Miroshnikov,
• Frank Seela and
• Igor A. Mikhailopulo

Beilstein J. Org. Chem. 2016, 12, 2588–2601, doi:10.3762/bjoc.12.254

• obtained from commercial suppliers and were used without further purification. The NMR and UV–vis spectra were recorded on Brucker Avance 500-DRX (Bruker, Germany) and Carry 100 spectrometers (Varian, USA), respectively. TLC was performed on TLC aluminium sheets covered with silica gel 60 F254. Low

Methylenelactide: vinyl polymerization and spatial reactivity effects

• Judita Britner and
• Helmut Ritter

Beilstein J. Org. Chem. 2016, 12, 2378–2389, doi:10.3762/bjoc.12.232

• ) with AIBN (A) and without initiator (B). UV–vis spectra of the reaction mixture with DPPH radical at the beginning (violet line, 0.23 mM) of the self-initiated polymerization of MLA and after 15 h (yellow line) in a range from 380–800 nm (cMLA = 1.8 mol L−1, 70 °C). Copolymer composition curves for the

High performance p-type molecular electron donors for OPV applications via alkylthiophene catenation chromophore extension

• Paul B. Geraghty,
• Calvin Lee,
• Jegadesan Subbiah,
• Wallace W. H. Wong,
• James L. Banal,
• Mohammed A. Jameel,
• Trevor A. Smith and
• David J. Jones

Beilstein J. Org. Chem. 2016, 12, 2298–2314, doi:10.3762/bjoc.12.223

• at around 570 nm, therefore indicating that the underlying packing structures are not significantly altered through side-chain substitution. To better understand the annealing process UV–vis spectra have been replotted for each material, see Figure 6 (and Supporting Information File 1, Figures S9.1

• those used to collect the UV–vis spectra above, with selected graphs shown in Figure 7, and extracted data in Table 2. The full spectra are presented in Supporting Information File 1, Figure S9.3. The as-cast films do not contain simple symmetric emission bands, indicating a significant level of

• obtain the UV–vis spectra, were heated to above the NLC phase change temperature, and collected fluorescence emission spectra are shown in Figure 10. It is clear that when the thin films are heated to 220 °C, i.e., above the NLC phase change temperature, a second blue shifted peak appears at 730 nm

Thiophene-forming one-pot synthesis of three thienyl-bridged oligophenothiazines and their electronic properties

• Dominik Urselmann,
• Konstantin Deilhof,
• Bernhard Mayer and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2016, 12, 2055–2064, doi:10.3762/bjoc.12.194

• S4). In addition this behavior underlines that no aggregation of the molecules has to be taken into account at the concentration level of absorption and emission spectroscopy. In the UV–vis spectra, most characteristically, four absorption bands are found, three at shorter wavelengths arising from

• match of experimentally and computationally determined absorption bands cannot be expected for conformationally flexible complex molecules with extended π-conjugation, the trend of the longest wavelength absorption bands from the UV–vis spectra is correctly reproduced. Furthermore, for all three methods

• oligophenothiazines 3a, 3b, and 3c, computed UV–vis spectra of ZINDO-CI and TD-DFT (B3LYP, CAM-B3LYP) calculated structures of 3a, 3b, and 3c, computed FMOs (frontier molecular orbitals) of the calculated structures 3a, 3b, and 3c. Supporting Information File 272: Experimental and analytical data. Acknowledgements

Synthesis and properties of fluorescent 4′-azulenyl-functionalized 2,2′:6′,2″-terpyridines

• Adrian E. Ion,
• Liliana Cristian,
• Mariana Voicescu,
• Masroor Bangesh,
• Augustin M. Madalan,
• Daniela Bala,
• Constantin Mihailciuc and
• Simona Nica

Beilstein J. Org. Chem. 2016, 12, 1812–1825, doi:10.3762/bjoc.12.171

• (working solution obtained by dilution with water). UV–vis spectra were recorded after each addition on a Varian Cary 100 spectrophotometer using 1 cm quarts cells and methanol/water as solvent. The fluorescence emission and excitation spectra were recorded with a Jasco FP-6500 spectrofluorometer equipped

Amidofluorene-appended lower rim 1,3-diconjugate of calix[4]arene: synthesis, characterization and highly selective sensor for Cu²⁺

• Rahman Hosseinzadeh,
• Mohammad Nemati,
• Reza Zadmard and
• Maryam Mohadjerani

Beilstein J. Org. Chem. 2016, 12, 1749–1757, doi:10.3762/bjoc.12.163

• , Figures S1–S11). General procedure for UV–vis experiments The evaluation of cation-ligand interaction was performed with UV–vis spectroscopy. The UV–vis measurement of receptor L in CH3CN exhibited three absorption peaks at 282, 290, and 314 nm. Furthermore, the variation of UV–vis spectra was monitored

• spectrometer. CDCl3 and CD3CN were used as NMR solvents and TMS as internal standard. High-resolution mass spectra (HRMS) were recorded on a Qstar ESI-q-TOF mass spectrometer (Applied Biosystems, Darmstadt, Germany). SPEKOL 2000 Analytik Jena spectrometer were used for recording of UV–vis spectra in

From N-vinylpyrrolidone anions to modified paraffin-like oligomers via double alkylation with 1,8-dibromooctane: access to covalent networks and oligomeric amines for dye attachment

• Daniela Obels,
• Melanie Lievenbrück and
• Helmut Ritter

Beilstein J. Org. Chem. 2016, 12, 1395–1400, doi:10.3762/bjoc.12.133

• . The synthesis was carried out under mild conditions with a slight excess of DFA to achieve high conversions. Therefore, the 1H NMR and UV–vis spectra, respectively still showed signals of ca. 20 mol % of DFA [43] and the corresponding data are given in Supporting Information File 1. The second fluoro

• the anthraquinone dye [44]. Thus, this reaction can also be followed with the naked eye. Furthermore, the conversion of oligomer 6 was verified with UV–vis spectroscopy (Figure 2). Accordingly, the different UV–vis spectra (Figure 2) of DFA, oligomer 5 and the disubstituted anthraquinone dye in 6

• water swellable network 3a and 3b. Photographs of water-swollen polymer disks consisting of 1 mol % (3a) and 2.5 mol % (3b) of 2a as cross linker. UV–vis spectra of oligomers 5 (c = 0.16 g/mL, red), 6 (c = 0.63 g/mL, blue) and DFA (c = 0.016 g/mL, grey). Alkylation of N-VP with 1,8-dibromooctane

On the mechanism of imine elimination from Fischer tungsten carbene complexes

• Philipp Veit,
• Christoph Förster and
• Katja Heinze

Beilstein J. Org. Chem. 2016, 12, 1322–1333, doi:10.3762/bjoc.12.125

• S27). In full accordance with the above observations, UV–vis spectra recorded during the thermal treatment of W(CO)5(E-2) in toluene (100 °C) show the clean decay of the characteristic bands of W(CO)5(E-2) at 360 and 391 nm. The ferrocene based absorption band around 500 nm remains essentially

The role of alkyl substituents in deazaadenine-based diarylethene photoswitches

• Christopher Sarter,
• Michael Heimes and
• Andres Jäschke

Beilstein J. Org. Chem. 2016, 12, 1103–1110, doi:10.3762/bjoc.12.106

• other spectra are presented in Supporting Information File 1 Figures S1–S5. Figure 2 and Figure S1 (Supporting Information File 1) show the changes in the UV–vis spectra upon irradiation with UV light (366 nm, hand lamp) in acetonitrile. Three differences are immediately apparent between the two classes