Hydroquinone–pyrrole dyads with varied linkers

• Hao Huang,
• Christoffer Karlsson,
• Maria Strømme,
• Martin Sjödin and
• Adolf Gogoll

Beilstein J. Org. Chem. 2016, 12, 89–96, doi:10.3762/bjoc.12.10

• , Box 576, SE-751 23 Uppsala, Sweden 10.3762/bjoc.12.10 Abstract A series of pyrroles functionalized in the 3-position with p-dimethoxybenzene via various linkers (CH2, CH2CH2, CH=CH, C≡C) has been synthesized. Their electronic properties have been deduced from 1H NMR, 13C NMR, and UV–vis spectra to

• -3c. This illustrates the well-known caveat for chemical shift predictions [26]. To assess the electronic properties as indicated in UV–vis spectra, reference spectra of pyrrole, DMB, 1,4-dimethoxy-2-vinylbenzene (DMB-VI), and 1,4-dimethoxy-2-ethynylbenzene (DMB-EN) were recorded. The UV–vis spectra

• therefore a measure of the charge delocalization in the molecule. This effect can be viewed as an increased delocalized system that results in a lowering of the HOMO–LUMO gap, which can be traced by the red shifts of the highest wavelength absorption in UV–vis spectra (Table 1). The extent of conjugation

Iron complexes of tetramine ligands catalyse allylic hydroxyamination via a nitroso–ene mechanism

• David Porter,
• Belinda M.-L. Poon and
• Peter J. Rutledge

Beilstein J. Org. Chem. 2015, 11, 2549–2556, doi:10.3762/bjoc.11.275

• chromatographs were equipped with split/splitless capillary inlets and flame ionization detectors (FID). UV–vis spectra were recorded on a Varian Carey 4000 UV–vis spectrophotometer. Synthesis of iron complexes 4, 5 and 6 and N-Boc-hydroxylamine (8) Tris(2-pyridylmethyl)amine (TPA, 1) [48] and N,N′-bis(2

Urethane tetrathiafulvalene derivatives: synthesis, self-assembly and electrochemical properties

• Xiang Sun,
• Guoqiao Lai,
• Zhifang Li,
• Yuwen Ma,
• Xiao Yuan,
• Yongjia Shen and
• Chengyun Wang

Beilstein J. Org. Chem. 2015, 11, 2343–2349, doi:10.3762/bjoc.11.255

• •+) were formed, which was possibly supported by the increase of the absorption bands around 600–900 nm (Figure 5a) [2][4]. Moreover, the UV–vis spectra of self-assembled nanoribbons doped with iodine were collected. It was concluded that the assembled solid structures were maintained. Figure 5b shows the

• glass substrates (drop-coated from diluted T1 or T2 solution). The UV–vis spectra of T1 (a) and T2 (b) at different concentrations in ethyl acetate. IR spectra of (a) T1, (b) T2, (c) TCNQ, (d) T2/TCNQ, and (e) T1/TCNQ. (a) UV–vis spectra of T1 solutions TCNQ and T1/TCNQ in ethyl acetate (1 × 10−3 M). (b

• ) UV–vis spectra of T1 before and after iodine doping for 30 min. Cyclic voltammograms of T1 and T2 in DCM. Conditions: 0.1 M tetrabutylammonium hexafluorophosphate, 100 mV s−1, Ag/AgCl as the reference electrode, Pt wire as the counter electrode, and glassy carbon as the working electrode; measured

Effective ascorbate-free and photolatent click reactions in water using a photoreducible copper(II)-ethylenediamine precatalyst

• Redouane Beniazza,
• Natalia Bayo,
• Florian Molton,
• Carole Duboc,
• Stéphane Massip,
• Nathan McClenaghan,
• Dominique Lastécouères and
• Jean-Marc Vincent

Beilstein J. Org. Chem. 2015, 11, 1950–1959, doi:10.3762/bjoc.11.211

• Cambridge Crystallographic Data Centre as deposition CCDC 1414149 for 4, and CCDC 1410011 for 1. Evolution of the UV–vis spectra of deaerated (freeze-pump-thaw degassed, sealed quartz cuvettes) THF (left) or water (right) solutions (3 mL) of complex 1 (2 mM) under irradiation at 365 nm using a TLC lamp

Synthesis and spectroscopic properties of β-triazoloporphyrin–xanthone dyads

• Dileep Kumar Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2015, 11, 1434–1440, doi:10.3762/bjoc.11.155

• , 12b and 13b), and zinc porphyrins (Zn-TPP, 6c, 6f, 7a and 13a) are shown in Figure 1a–c. Besides the Soret and Q-bands, an additional absorption band was also observed at ~340 nm in the UV–vis spectra of these porphyrin–xanthone conjugates due to the presence of xanthone moiety (Figure 1a–c) which

• applications. (a) Electronic absorption spectra of Cu-TPP, 6a, 7e, 12a and 13c. (b) Electronic absorption spectra of TPP, 6b, 7b, 12b and 13b. (c) Electronic absorption spectra of Zn-TPP, 6c, 6f, 7a and 13a in CHCl3 (1.5 × 10−6 mol L−1) at 298 K and inset shows the expanded UV–vis spectra with Q-bands. (d

Synthesis of photoresponsive cholesterol-based azobenzene organogels: dependence on different spacer lengths

• Yuchun Ren,
• Bin Wang and
• Xiuqing Zhang

Beilstein J. Org. Chem. 2015, 11, 1089–1095, doi:10.3762/bjoc.11.122

• , respectively. It should be emphasized that such reversible spectral transformation could be repeated several times. The trans-to-cis isomerization of the azobenzenze unit had been demonstrated. Compounds M2, M5, M6, and M12 have the same recoverable photoresponsive properties as M0. Their UV–vis spectra were

• organogelators and soft matter. Changes in the absorption over time in the UV–vis spectra of dilute THF solution of M0: (a) upon UV-light irradiation (λ = 365 nm) and (b) upon visible-light irradiation (λ = 450 nm) of the solution obtained after irradiation of 365 nm. DSC thermogram of the compounds M0-n

Single-molecule conductance of a chemically modified, π-extended tetrathiafulvalene and its charge-transfer complex with F₄TCNQ

• Raúl García,
• M. Ángeles Herranz,
• Edmund Leary,
• M. Teresa González,
• Gabino Rubio Bollinger,
• Marius Bürkle,
• Linda A. Zotti,
• Yoshihiro Asai,
• Fabian Pauly,
• Juan Carlos Cuevas,
• Nicolás Agraït and
• Nazario Martín

Beilstein J. Org. Chem. 2015, 11, 1068–1078, doi:10.3762/bjoc.11.120

• experimental procedures for the synthesis and characterization of 5, break junction experiments and theoretical methods. Acknowledgements We thank Dr. Jose Manuel Santos Barahona for help with preparing the CT complex with TCNQ, and recording and interpreting the UV–vis spectra. Financial support by the

Carboxylated dithiafulvenes and tetrathiafulvalene vinylogues: synthesis, electronic properties, and complexation with zinc ions

• Yunfei Wang and
• Yuming Zhao

Beilstein J. Org. Chem. 2015, 11, 957–965, doi:10.3762/bjoc.11.107

• –vis spectra of TTFVs 5 and 6 (solid lines) and DTF 4 and 7 (dashed lines). Compounds 4 and 5 were measured in CH2Cl2, while compounds 6 and 7 were in THF. Cyclic voltammograms of compounds 4–9. Experimental conditions: supporting electrolyte: Bu4NBF4 (0.1 M), working electrode: glassy carbon, counter

• containing Et3N/EtOH (6 mL, 1:2). The jar was sealed and left standing for 2 days. The precipitate formed in the vial was collected by centrifugation and rinsed with EtOH to afford Zn-DTF 9 (15.1 mg) as a yellow solid. FTIR (neat): 3360, 2990, 2916, 1585, 1559, 1538, 1494, 1392, 1187, 803, 768, 472 cm−1. UV

Synthesis and characterization of the cyanobenzene-ethylenedithio-TTF donor

• Sandrina Oliveira,
• Dulce Belo,
• Isabel C. Santos,
• Sandra Rabaça and
• Manuel Almeida

Beilstein J. Org. Chem. 2015, 11, 951–956, doi:10.3762/bjoc.11.106

• investigated by UV–vis absorption spectroscopy in dichloromethane solution. The UV–vis spectra in DCM (Figure S6 in Supporting Information File 1) showed π–π* transitions typical of TTF donors [21], with an intense absorption band centred at approximately at 231 nm and other weaker bands at 269, 305 and 329 nm

• as solvents respectively and TMS the internal reference. UV–vis spectra were recorded on an UV-1800 Shimadzu spectrophotometer. Cyclic voltammetry data were obtained using a BAS C3 Cell Stand. The voltammograms were obtained at room temperature with a scan rate of 100 mV/s, platinum wire working and

Tuning of tetrathiafulvalene properties: versatile synthesis of N-arylated monopyrrolotetrathiafulvalenes via Ullmann-type coupling reactions

• Vladimir A. Azov,
• Diana Janott,
• Dirk Schlüter and
• Matthias Zeller

Beilstein J. Org. Chem. 2015, 11, 860–868, doi:10.3762/bjoc.11.96

• reaction with bromophenol 8d to form the adduct 4f also confirmed the possibility of the reaction with hydroxy-substituted aryl derivatives, paving the way for application of this method with non-protected calix[4]arene derivatives [27]. Compounds 4a–c,e,f (Figure 3) display UV–vis spectra typical for TTF

• = 0.86 V, E1/2ox3 = 1.77 V. Molecular structures of tetrathiafulvalenes 1, bis-pyrrolotetrathiafulvalenes 2 and monopyrrolotetrathiafulvalenes 3. Copper(I) ligands 9a and 9b. UV–vis spectra of compounds 4a,c–f (CH2Cl2, c = 4 × 10−5 M). Cyclic voltammograms of compounds 4a,c [22] and 4d–f (plotted vs SCE

Impact of multivalent charge presentation on peptide–nanoparticle aggregation

• Daniel Schöne,
• Boris Schade,
• Christoph Böttcher and
• Beate Koksch

Beilstein J. Org. Chem. 2015, 11, 792–803, doi:10.3762/bjoc.11.89

• ) Dynamic light scattering of 0.05 µM Au/MUA nanoparticles at pH 9. (B) Cryo TEM image of 0.05 µM Au/MUA nanoparticles at pH 9. (C) UV–vis spectra of 0.05 µM Au/MUA nanoparticles at pH 9 and in the presence of 30 µM VW05. (D) Time and concentration dependent shift in the absorption maximum of 0.05 µM Au/MUA

TTFs nonsymmetrically fused with alkylthiophenic moieties

• Rafaela A. L. Silva,
• Bruno J. C. Vieira,
• Marta M. Andrade,
• Isabel C. Santos,
• Sandra Rabaça,
• Dulce Belo and
• Manuel Almeida

Beilstein J. Org. Chem. 2015, 11, 628–637, doi:10.3762/bjoc.11.71

• internal reference. UV–vis spectra were recorded on a UV-1800 Shimadzu spectrophotometer. Mass spectra were obtained in QIT/MS Bruker HCT by collision-induced dissociation (CID). 5-(tert-Butyl)thieno[2,3-d][1,3]dithiol-2-one (I): 0.536 g of aluminum chloride in 12 mL dichloromethane was cooled to −78 °C in

Further exploration of the heterocyclic diversity accessible from the allylation chemistry of indigo

• Alireza Shakoori,
• John B. Bremner,
• Mohammed K. Abdel-Hamid,
• Anthony C. Willis,
• Rachada Haritakun and
• Paul A. Keller

Beilstein J. Org. Chem. 2015, 11, 481–492, doi:10.3762/bjoc.11.54

• intermediate, structure 27, together with comparison data for analogous structures from 9 and 7. In vitro antiplasmodial, anticancer, and antitubercular activity of compounds 12–14, 17, 18, 32–35, 8, 9, and 31.a Supporting Information Supporting Information File 98: Experimental procedures, UV–vis spectra

Synthesis and chemosensing properties of cinnoline-containing poly(arylene ethynylene)s

• Natalia A. Danilkina,
• Petr S. Vlasov,
• Semen M. Vodianik,
• Andrey A. Kruchinin,
• Yuri G. Vlasov and
• Irina A. Balova

Beilstein J. Org. Chem. 2015, 11, 373–384, doi:10.3762/bjoc.11.43

• at the optimal excitation wavelength of 425 nm which corresponds to the absorption bands at ≈425 nm in UV–vis spectra of both samples (Figure 6). An additional ethynyl moiety in the repeating unit of olygomer 10b led to the increase in quantum yield from 1% for 10a to 2% for 10b, while qualitative

A facile synthesis of functionalized 7,8-diaza[5]helicenes through an oxidative ring-closure of 1,1’-binaphthalene-2,2’-diamines (BINAMs)

• Youhei Takeda,
• Masato Okazaki,
• Yoshiaki Maruoka and
• Satoshi Minakata

Beilstein J. Org. Chem. 2015, 11, 9–15, doi:10.3762/bjoc.11.2

• Supporting Information File 2: Experimental procedures, characterization data, copies of NMR charts, UV–vis spectra, cyclic voltammograms, and TGA profiles. Acknowledgements This research was partly supported by the research Grant from The Murata Science Foundation, the Sasakawa Scientific Research Grant

Synthesis and characterization of a new photoinduced switchable β-cyclodextrin dimer

• Florian Hamon,
• Claire Blaszkiewicz,
• Marie Buchotte,
• Estelle Banaszak-Léonard,
• Hervé Bricout,
• Sébastien Tilloy,
• Eric Monflier,
• Christine Cézard,
• Laurent Bouteiller,
• Christophe Len and
• Florence Djedaini-Pilard

Beilstein J. Org. Chem. 2014, 10, 2874–2885, doi:10.3762/bjoc.10.304

• trans to its cis form resulting in a marked change in the UV–vis spectra. As the irradiation continued, the absorption band at around 320 nm gradually decreased while the bands at 420 nm and 250 nm slightly increased. This change is clearly due to the simple, but partial, isomerization of the azo groups

A novel 4-aminoantipyrine-Pd(II) complex catalyzes Suzuki–Miyaura cross-coupling reactions of aryl halides

• Claudia A. Contreras-Celedón,
• Darío Mendoza-Rayo,
• José A. Rincón-Medina and
• Luis Chacón-García

Beilstein J. Org. Chem. 2014, 10, 2821–2826, doi:10.3762/bjoc.10.299

• (Scheme 1). The 4-AAP–Pd(II) complex is thermally stable, not sensitive to oxygen or moisture, and highly soluble in common solvents such as CHCl3, CH2Cl2 and AcOEt. The newly synthesized 4-AAP–Pd(II) complex was characterized by UV–vis, FTIR, 1H, 13C NMR spectroscopy and MS (Table 1). The UV–vis spectra

Linear-g-hyperbranched and cyclodextrin-based amphiphilic block copolymer as a multifunctional nanocarrier

• Yamei Zhao,
• Wei Tian,
• Guang Yang and
• Xiaodong Fan

Beilstein J. Org. Chem. 2014, 10, 2696–2703, doi:10.3762/bjoc.10.284

•  3 presents the UV–vis spectra of the LND solution in the presence of MP1, MP2 and MP3 in buffer solution. Obviously, the peak intensity of the LND solutions gradually decreased at 272 nm when the samples changed from MP1 to MP2, and finally to MP3 at the same concentration. In general, the

• . Experimental Experimental details can be found in the Supporting Information. Particle size distributions of MP1, MP2, and MP3 at 25 °C as determined by DLS. TEM images of P1 (A), P2 (B) and P3 (C) micelles. UV–vis spectra of LND solutions in the presence of MP1, MP2 and MP3 in buffer solutions. Particle size

Encapsulation of biocides by cyclodextrins: toward synergistic effects against pathogens

• Véronique Nardello-Rataj and
• Loïc Leclercq

Beilstein J. Org. Chem. 2014, 10, 2603–2622, doi:10.3762/bjoc.10.273

• potentiometric titration whereas the stability constant of the Ag0–CD complex was determined from the UV–vis spectra. The constants were estimated at 360 and 3.07 × 106 M−1 for Ag0 and Ag+, respectively. Antibacterial activities against E. coli and S. aureus were determined for the fabrics grafted with CD and

A small azide-modified thiazole-based reporter molecule for fluorescence and mass spectrometric detection

• Stefanie Wolfram,
• Hendryk Würfel,
• Stefanie H. Habenicht,
• Christine Lembke,
• Phillipp Richter,
• Eckhard Birckner,
• Rainer Beckert and
• Georg Pohnert

Beilstein J. Org. Chem. 2014, 10, 2470–2479, doi:10.3762/bjoc.10.258

• receive BNS (6). Furthermore, we utilized N-(3-azidopropyl)-7-nitrobenzo[c][1,2,5]oxadiazol-4-amine (NBD, 9), a cheap fluorophore previously used for probes [1][31] or as fluorescent tag [32][33] (Figure 2). UV–vis spectra of all substances were recorded in an aqueous solution containing 20% THF (v/v

• . Experimental Synthesis Experimental details are available in Supporting Information File 1. Sample preparation and measurements UV–vis and fluorescence spectroscopy Solutions of each fluorophore in THF/water (20 µM, 20:80; v/v) were prepared out of 5 mM stock solutions in DMSO. UV–vis spectra were recorded

• bromine modified DNS system 6. UV–vis spectra of 20 µM solutions of the azide modified fluorophores BPT (1), DNS (8), NBD (9) and BNS (6) in THF/water (20:80; v/v). Normalized absorbance and fluorescence of BPT (1) in 20% THF/80% water (v/v), excitation at 374 nm. Peak area of 100 pmol BPT (1), DNS (8

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