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Search for "UV–vis spectra" in Full Text gives 239 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

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

Graphical Abstract
  • spectrometer equipped with a diamond ATR unit. UVvis spectra were recorded with a Shimadzu UV-1800, fluorescence spectra with a Shimadzu RF-5301PC spectrometer. Compounds 1 [41] and 5 [44] were prepared according to literature procedures. All other starting materials were commercially available. XPS of SAMs
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Published 26 Apr 2019

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

Graphical Abstract
  • using CDCl3. IR spectra were recorded with a FTIR spectrometer. UVvis spectra were taken by a SHIMADZU UV-3600 Plus spectrophotometer. Mass spectra were measured by a Mass Spectrometric Thermo Fisher Scientific LTQ Orbitrap XL, performed by the Natural Science Center for Basic Research and Development
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Published 10 Apr 2019

Coordination chemistry and photoswitching of dinuclear macrocyclic cadmium-, nickel-, and zinc complexes containing azobenzene carboxylato co-ligands

  • Jennifer Klose,
  • Tobias Severin,
  • Peter Hahn,
  • Alexander Jeremies,
  • Jens Bergmann,
  • Daniel Fuhrmann,
  • Jan Griebel,
  • Bernd Abel and
  • Berthold Kersting

Beilstein J. Org. Chem. 2019, 15, 840–851, doi:10.3762/bjoc.15.81

Graphical Abstract
  • chamber of a UV–vis spectrometer. Figure 13 shows the corresponding UVvis spectra, which were recorded directly after sample preparation. As can be seen, the intensity of the π→π* band at 325 nm for the trans-azobenzene carboxylate decreases with increasing irradiation time, while the intensity of the n
  • Tensor 27 FTIR spectrometer. UVvis spectra were recorded on a Jasco V-670 UV–vis/near-IR spectrophotometer. Elemental analyses were carried out with a Vario EL – elemental analyzer. NMR spectra were recorded on a Bruker Fourier 300 spectrometer or Avance DRX 400 at 298 K. 1H and 13C chemical shifts
  • ) and 1.0 T (4). The solid lines represent the best theoretical fit to Equation 1 (see text). Experimental and calculated values are provided as Supporting Information File 1. UVvis spectra of Hazo-H (red line), [Cd2L(μ-Cl)](ClO4) (black line) and [Cd2L(μ-azo-H)]ClO4 (1, blue line) in acetonitrile
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Published 03 Apr 2019

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

Graphical Abstract
  • ) was separated from the unreacted starting materials, and analyzed by UV–vis spectroscopy (Figure 3). Comparison of the UVvis spectra of 6a and 10a/10a’ showed the successful conjugation of the DAG with the coumarin moiety [47]. Conclusion The implementation of ball milling techniques has provided the
  • level. Biologically relevant molecules made, used or derivatized by mechanochemistry. Isomeric diacyl-sn-glycerols (DAGs). UVvis spectra of DAG 6a (dotted line) and conjugated DAGs 10a and 10a’ as a mixture (10a/10a’ 72:28) in toluene at a concentration of 0.5 μM. Synthetic route to access protected
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Published 29 Mar 2019

Synthesis of polydicyclopentadiene using the Cp2TiCl2/Et2AlCl catalytic system and thin-layer oxidation of the polymer in air

  • Zhargolma B. Bazarova,
  • Ludmila S. Soroka,
  • Alex A. Lyapkov,
  • Мekhman S. Yusubov and
  • Francis Verpoort

Beilstein J. Org. Chem. 2019, 15, 733–745, doi:10.3762/bjoc.15.69

Graphical Abstract
  • Uniwise International Co., Ltd., 99% pure) was purified from stabilizers by distillation under reduced pressure (≈6,6 kPa). All operations with monomer and catalyst were carried out in a glove box MBraun Labstar provided with an argon atmosphere. UVvis spectra of catalyst system solutions were registered
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Published 20 Mar 2019

Synthesis of functionalized diazocines for application as building blocks in photo- and mechanoresponsive materials

  • Widukind Moormann,
  • Daniel Langbehn and
  • Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 727–732, doi:10.3762/bjoc.15.68

Graphical Abstract
  • mechanoresponsive polymers such as polyurethanes, polyesters, polyamides, polyureas and polyolefines. (a) Isomerization of parent diazocine 1. Distances of carbon atoms para to the ethylene bridge were determined at the B3LYP/6-31g* level of DFT [23]. (b) UVvis spectra of parent diazocine 1 (left), 3,3
  • ’-diaminodiazocine 2 (center) and 4,4’-diaminodiazocine 3 (right). Continuous lines: 100% cis and dashed lines: PSS (385 nm) at 298.15 K in acetonitrile. Synthesized target diazocines 4–7 for applications in responsive materials. UVvis spectra of 3,3’-diaminodiazocine 2 (left), 3,3’-di(aminomethyl)diazocine 6a
  • . Supporting Information Supporting Information File 346: Analytical equipment, experimental procedures, NMR and UVvis spectra. Acknowledgements The authors gratefully acknowledge financial support by the Deutsche Forschungsgesellschaft (DFG) within the Sonderforschungsbereich 677, “Function by Switching”.
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Published 20 Mar 2019

Polyaminoazide mixtures for the synthesis of pH-responsive calixarene nanosponges

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

Beilstein J. Org. Chem. 2019, 15, 633–641, doi:10.3762/bjoc.15.59

Graphical Abstract
  • according to the procedures reported in literature. Instrumentation. UVvis spectra were recorded on a Beckmann Coulter DU 800 spectrophotometer, equipped with a Peltier thermostatic apparatus. FTIR spectra on powders were acquired on a Bruker VERTEX70 instrumentation. NMR spectra were recorded on a Bruker
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Published 12 Mar 2019

Silanediol versus chlorosilanol: hydrolyses and hydrogen-bonding catalyses with fenchole-based silanes

  • Falco Fox,
  • Jörg M. Neudörfl and
  • Bernd Goldfuss

Beilstein J. Org. Chem. 2019, 15, 167–186, doi:10.3762/bjoc.15.17

Graphical Abstract
  • otherwise specified. NMR spectra were recorded on a Bruker Avance II 300 instrument. UVvis spectra were recorded by using a Perkin Elmer Lambda35 spectrometer. The samples were placed in quartz cells of 1 cm path length. NMR spectra, UVvis spectra, crystal data and the coordinates of computed stationary
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Published 18 Jan 2019

Mechanistic studies of an L-proline-catalyzed pyridazine formation involving a Diels–Alder reaction with inverse electron demand

  • Anne Schnell,
  • J. Alexander Willms,
  • S. Nozinovic and
  • Marianne Engeser

Beilstein J. Org. Chem. 2019, 15, 30–43, doi:10.3762/bjoc.15.3

Graphical Abstract
  • ] scale. UVvis spectra were measured on a Lambda 18 instrument from Perkin Elmer and fluorescence spectra were measured on a LS50B instrument from Perkin Elmer. All EI spectra were measured on a MAT 95 XL instrument from Thermo Finnigan and ESI spectra of synthesized compounds were measured with either
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Published 03 Jan 2019

Olefin metathesis catalysts embedded in β-barrel proteins: creating artificial metalloproteins for olefin metathesis

  • Daniel F. Sauer,
  • Johannes Schiffels,
  • Takashi Hayashi,
  • Ulrich Schwaneberg and
  • Jun Okuda

Beilstein J. Org. Chem. 2018, 14, 2861–2871, doi:10.3762/bjoc.14.265

Graphical Abstract
  • different analytical methods [56]. Structural integrity of the β-barrel fold was confirmed by CD spectroscopy. ICP–OES was used to determine the metal content. A little less than one metal center per protein molecule was found to be present. Additional absorption bands in the UVvis spectra around λ = 380
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Published 19 Nov 2018

Synthesis of mono-functionalized S-diazocines via intramolecular Baeyer–Mills reactions

  • Miriam Schehr,
  • Daniel Hugenbusch,
  • Tobias Moje,
  • Christian Näther and
  • Rainer Herges

Beilstein J. Org. Chem. 2018, 14, 2799–2804, doi:10.3762/bjoc.14.257

Graphical Abstract
  • nπ* absorption maxima are in a range between 508 nm to 516 nm (for UVvis spectra measured in acetone see Supporting Information File 1). The half-lives vary from 24.8 h to 6.7 d. For the carboxylic acid functionalized S-diazocine 4 the two isomers generated after irradiation with 405 nm could be
  • separated by chromatography and the UVvis spectra of the pure cis and trans isomers could be measured in an acetonitrile/water mixture. Figure 2 shows the UV spectra of the pure cis and trans isomers of 4. The nπ* band of the cis isomer displays an absorption maxima at λmax = 392 nm. Upon irradiation with
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Published 07 Nov 2018

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

Graphical Abstract
  • under 355 nm irradiation, a broad transient absorption from 300 nm to 390 nm that did not decline over the measurement time (up to 10 µs, see Supporting Information File 1). In the UVvis spectra recorded after the LFP experiment a significant change in absorption in the 300–370 nm region was observed
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Published 27 Sep 2018

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

Graphical Abstract
  • properties of the 1-R complexes, UV–vis absorption measurements were conducted. As shown in Figure 2, three absorption bands are observed in the UVvis spectra. The lowest energy absorption appearing as a shoulder at 645 to 660 nm, is associated with the d–d transitions involving 1A1 → 1T1 and 1A1 → 1T2 for
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Published 05 Sep 2018

Coordination-driven self-assembly of discrete Ru6–Pt6 prismatic cages

  • Aderonke Ajibola Adeyemo and
  • Partha Sarathi Mukherjee

Beilstein J. Org. Chem. 2018, 14, 2242–2249, doi:10.3762/bjoc.14.199

Graphical Abstract
  • form a single framework architecture through a one-pot self-assembly strategy. 1H NMR of 3b in CD3OD. UVvis spectra of the metalloligand 2 and heterometallic prismatic cages 3a and 3b in methanol (1.0 × 10−5 M) at 298 K. ESIMS spectrum of 3a in methanol. Inset: experimentally observed isotopic
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Published 27 Aug 2018

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

Graphical Abstract
  • macroscopic as well as on the molecular level, even the most efficient switch is useless, if no observable output is generated which helps to detect the switching process [30]. A simple “read out” is provided by the optical properties of TTF in its different switching states. For example, UVvis spectra of
  • changes. UVvis spectra and photographs of TTF 2 in its three stable oxidation states (black line = 2, orange line = 2●+, blue line = 22+). Structure and conformations of two TTF dimers in solution, the mixed-valence and the radical-cation dimer. (a) The isomerism problem of TTF. (b)–(d) Major synthetic
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Published 20 Aug 2018

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

Graphical Abstract
  • solutions dried on the surface of the KBr disc. Melting points were measured using a Stuart SMP10 apparatus. UV–vis absorbance spectra The UVvis-spectra were recorded on a Lambda 35 UV/VIS spectrophotometer (Perkin Elmer Instruments) in an optical cell with 1.0 cm light pass at 298 K. Dynamic light
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Published 31 Jul 2018

Efficient catenane synthesis by cucurbit[6]uril-mediated azide–alkyne cycloaddition

  • Antony Wing Hung Ng,
  • Chi-Chung Yee,
  • Kai Wang and
  • Ho Yu Au-Yeung

Beilstein J. Org. Chem. 2018, 14, 1846–1853, doi:10.3762/bjoc.14.158

Graphical Abstract
  • ; bisolated yield by preparative HPLC. Supporting Information Supporting Information File 290: Detailed experimental procedures and characterization data (MS, MS2, 1H and 13C NMR and UVvis spectra). Acknowledgements The work described in this paper was supported by the Croucher Foundation and a grant from
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Published 20 Jul 2018

First thia-Diels–Alder reactions of thiochalcones with 1,4-quinones

  • Grzegorz Mlostoń,
  • Katarzyna Urbaniak,
  • Paweł Urbaniak,
  • Anna Marko,
  • Anthony Linden and
  • Heinz Heimgartner

Beilstein J. Org. Chem. 2018, 14, 1834–1839, doi:10.3762/bjoc.14.156

Graphical Abstract
  • spectra were registered with a FTIR NEXUS spectrometer (as film or KBr pellets). UVvis spectra were recorded using a UV–vis JASCO V-630 spectrophotometer. Melting points were determined in capillaries with a Stuart SMP30 apparatus with automatic temperature monitoring. Starting materials: 1,4
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Published 19 Jul 2018

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

Graphical Abstract
  • -); ESIMS 189.0878 (calcd for C8H8N6 + H+, 189.0883). UVvis spectra were recorded on a Bruker DU 800 spectrophotometer, equipped with a Peltier thermostatic apparatus. FTIR spectra (nujol) were recorded on an Agilent Technologies Cary 630 FTIR spectrometer. NMR spectra were acquired on a Bruker Avance II
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Published 20 Jun 2018

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

Graphical Abstract
  • IR-SEC experiments, the esters 1–4 were also probed by UV–vis-SEC investigations. The UVvis 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 UVvis 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 UVvis spectra of 1+–4+ is assigned to ligand-to-metal charge transfer (LMCT) transitions [79][81][82][83]. The bands
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Published 07 May 2018

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

Graphical Abstract
  • experimental procedures, copies of 1H and 13C NMR spectra, UVvis 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
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Published 13 Mar 2018

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

Graphical Abstract
  • 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 UVvis spectra of the
  • richer in bands than a typical ECD spectrum (just like IR spectra vs UVvis 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
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Published 08 Jan 2018

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

Graphical Abstract
  • . Interactions of the new derivatives of TO with dsDNA have been investigated by absorption and fluorescence spectroscopy. The longest wavelength absorption bands in the UVvis 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. UVvis spectra were measured on a Unicam 530 UV–vis spectrophotometer
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Published 28 Dec 2017

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

Graphical Abstract
  • (conversion of 11i to 12i). Or LiOH (3 equiv), MeOH/H2O (2:1), 0 °C, 30 min. B) UVvis 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
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Published 15 Nov 2017

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

Graphical Abstract
  • mononuclear phthalocyanine does not show any aggregation effect [74]. The aggregation behavior can be estimated from the UVvis 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 UVvis 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 UVvis spectra of benzene-fused dimers. Synthesis of trifluoroethoxy
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Published 27 Oct 2017
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