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

• spectrometer equipped with a diamond ATR unit. UV–vis 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

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

• using CDCl3. IR spectra were recorded with a FTIR spectrometer. UV–vis 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

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

• chamber of a UV–vis spectrometer. Figure 13 shows the corresponding UV–vis 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. UV–vis 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. UV–vis spectra of Hazo-H (red line), [Cd2L(μ-Cl)](ClO4) (black line) and [Cd2L(μ-azo-H)]ClO4 (1, blue line) in acetonitrile

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

• ) was separated from the unreacted starting materials, and analyzed by UV–vis spectroscopy (Figure 3). Comparison of the UV–vis 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). UV−vis 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

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

• 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. UV–vis spectra of catalyst system solutions were registered

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

• 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) UV–vis 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. UV–vis 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 UV–vis spectra. Acknowledgements The authors gratefully acknowledge financial support by the Deutsche Forschungsgesellschaft (DFG) within the Sonderforschungsbereich 677, “Function by Switching”.

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

• according to the procedures reported in literature. Instrumentation. UV–vis 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

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

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

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

• ] scale. UV–vis 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

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

• 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 UV–vis spectra around λ = 380

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

• nπ* absorption maxima are in a range between 508 nm to 516 nm (for UV–vis 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 UV–vis 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

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

• 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 UV–vis spectra recorded after the LFP experiment a significant change in absorption in the 300–370 nm region was observed

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

• properties of the 1-R complexes, UV–vis absorption measurements were conducted. As shown in Figure 2, three absorption bands are observed in the UV–vis 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

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

• form a single framework architecture through a one-pot self-assembly strategy. 1H NMR of 3b in CD3OD. UV–vis 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

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

• 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, UV–vis spectra of

• changes. UV–vis 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

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

• solutions dried on the surface of the KBr disc. Melting points were measured using a Stuart SMP10 apparatus. UV–vis absorbance spectra The UV–vis-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

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

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

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

• spectra were registered with a FTIR NEXUS spectrometer (as film or KBr pellets). UV–vis 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

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

• -); ESIMS 189.0878 (calcd for C8H8N6 + H+, 189.0883). UV–vis 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

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