Reversible end-to-end assembly of selectively functionalized gold nanorods by light-responsive arylazopyrazole–cyclodextrin interaction

• Maximilian Niehues,
• Patricia Tegeder and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2019, 15, 1407–1415, doi:10.3762/bjoc.15.140

• by changes of the ionic strength. Shortly after the addition of dAAP to the AuNR solution, UV–vis spectra were recorded (Figure 2a) indicating a strong LSPR shift of λ = 36 nm to λ = 757 nm while the TSPR band change is negligible. This indicates selective end-to-end assembly, whereas side-to-side or

Complexation of a guanidinium-modified calixarene with diverse dyes and investigation of the corresponding photophysical response

• Yu-Ying Wang,
• Yong Kong,
• Zhe Zheng,
• Wen-Chao Geng,
• Zi-Yi Zhao,
• Hongwei Sun and
• Dong-Sheng Guo

Beilstein J. Org. Chem. 2019, 15, 1394–1406, doi:10.3762/bjoc.15.139

• measured in HEPES buffer (10 mM, pH 7.4) at 25 °C. Instruments Steady-state fluorescence measurements were recorded in a conventional quartz cuvette (light path 10 mm) on a Cary Eclipse equipped with a Cary single-cuvette peltier accessory. UV–vis spectra were recorded in a quartz cuvette (light path 10 mm

Selective detection of DABCO using a supramolecular interconversion as fluorescence reporter

• Indrajit Paul,
• Debabrata Samanta,
• Sudhakar Gaikwad and
• Michael Schmittel

Beilstein J. Org. Chem. 2019, 15, 1371–1378, doi:10.3762/bjoc.15.137

• were established through 1H NMR (Figure 4) and UV–vis spectra (Figure 3b). DFT (B3LYP/6-31G(d)) calculations on rectangle 5 and sandwich complex 6 allow the modeling of the supramolecular architecture and provide some structural insights. The DFT computations demonstrate that the sandwich complex is

Enantioselective Diels–Alder reaction of anthracene by chiral tritylium catalysis

• Qichao Zhang,
• Jian Lv and
• Sanzhong Luo

Beilstein J. Org. Chem. 2019, 15, 1304–1312, doi:10.3762/bjoc.15.129

• cation. Also, FeBr3, a chiral Fe(III) monophosphate (M = FeBr2) 1c or even the bulky Fe(III) bisphosphate 2a promoted the dissociation of trityl bromide. In the latter case, the dissociation was estimated to be 54% by in-situ IR spectroscopy (UV–vis spectra were not applicable due to absorption overlap

N-doped carbon dots covalently functionalized with pillar[5]arenes for Fe³⁺ sensing

• Jia Gao,
• Ming-Xue Wu,
• Dihua Dai,
• Zhi Cai,
• Yue Wang,
• Wenhui Fang,
• Yan Wang and
• Ying-Wei Yang

Beilstein J. Org. Chem. 2019, 15, 1262–1267, doi:10.3762/bjoc.15.123

• –vis absorption peak at 295 nm. As expected, the UV–vis spectra of CCDs show two absorption peaks, one at 295 nm and the other at 340 nm, indicating that CP[5] has been linked on the surface of C-dots. The Fourier transform infrared spectra (FTIR) of C-dots, CN-dots, and CP[5] are shown in Figure 1d

• Fe3+ ions with high selectivity. TEM images of a) CCDs and b) CN-dots. c) UV–vis spectra of CP5, CN-dots, and CCDs. d) FTIR spectra of CP5, CN-dots, and CCDs. e) PXRD patterns of CP5, CN-dots, and CCDs. f) TGA curves of CN-dots and CCDs. a) Photographs of CN-dots and CCDs in aqueous media in natural

• fluorescence intensity versus the concentrations of Fe3+ ions. Experimental conditions: Slit widths: Ex. 5 nm, Em. 5 nm; λex = 340 nm. e) Spectral overlap of the UV–vis absorption spectrum of Fe3+ (red line) and fluorescence spectrum of CCDs (black line). f) UV–vis spectra of CCDs, Fe3+, and CCDs after the

Precious metal-free molecular machines for solar thermal energy storage

• Meglena I. Kandinska,
• Snejana M. Kitova,
• Vladimira S. Videva,
• Stanimir S. Stoyanov,
• Stanislava B. Yordanova,
• Stanislav B. Baluschev,
• Silvia E. Angelova and
• Aleksey A. Vasilev

Beilstein J. Org. Chem. 2019, 15, 1096–1106, doi:10.3762/bjoc.15.106

• are given in Supporting Information File 1. 4-(Aza-15-crown-5)benzocarbaldehyde (3) was synthesized using a slightly modified procedure [16][17]. UV–vis spectra were measured on a Unicam 530 UV–vis spectrophotometer in conventional quartz cells of 1 cm path length. The spectral bandwidth and the scan

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