Control over size, shape, and photonics of self-assembled organic nanocrystals

• Chen Shahar,
• Yaron Tidhar,
• Yunmin Jung,
• Haim Weissman,
• Sidney R. Cohen,
• Ronit Bitton,
• Iddo Pinkas,
• Gilad Haran and
• Boris Rybtchinski

Beilstein J. Org. Chem. 2021, 17, 42–51, doi:10.3762/bjoc.17.5

• , followed by the immediate evaporation of THF in a high-vacuum and adding water to reach a 1 × 10−4 M concentration. The self-assembly is instantaneous, as indicated by a color change from bright orange to pink in all systems. UV–vis spectra of compound 1 in aqueous medium exhibit a 0-0/0-1 vibronic band

• ) and Origin 7.5 (OriginLab) softwares. Chemical structure of compound 1 and UV–vis spectra in an aggregating aqueous medium and in the disaggregating solvent THF. Transmission electron microscopy (TEM) images (left, zoomed-out and zoomed-in; 1 × 10−4 M solutions of 1 deposited on TEM grids) and crystal

Construction of pillar[4]arene[1]quinone–1,10-dibromodecane pseudorotaxanes in solution and in the solid state

• Xinru Sheng,
• Errui Li and
• Feihe Huang

Beilstein J. Org. Chem. 2020, 16, 2954–2959, doi:10.3762/bjoc.16.245

• , chloroform-d, 298 K). Normalized UV–vis spectra: H (black); H upon adding 0.5 equiv of G (red); and H upon adding 1 equiv of G (blue). [H] = 3.00 mM. Chemical structures and schematic representation of (a) the pillar[4]arene[1]quinone H; (b) 1,10-dibromodecane (G); and (c) schematic representation of the

Optical detection of di- and triphosphate anions with mixed monolayer-protected gold nanoparticles containing zinc(II)–dipicolylamine complexes

• Lena Reinke,
• Julia Bartl,
• Marcus Koch and
• Stefan Kubik

Beilstein J. Org. Chem. 2020, 16, 2687–2700, doi:10.3762/bjoc.16.219

• nanoparticles NP4-Zn, NP10-Zn, NP25-Zn, and NP35-Zn (0.25 mg/mL) in water/methanol 1:2 (v/v) were treated with increasing amounts of either Na2HPO4, Na4P2O7, or Na5P3O10, and the UV–vis spectra of the resulting solutions were recorded between 350 and 800 nm to assess the effects of the salts on the position and

• the UV–vis spectra in a red shift of the SPR band. The corresponding spectrum is shown in orange in Figure 6. At somewhat higher concentrations, the intensity of the SPR band dropped because nanoparticle precipitation started to set in (red spectrum) and a further increase of the salt concentration

• mmol/L). UV–vis spectra of NP10-Zn (0.25 mg/mL in the initial measurement) in water/methanol 1:2 (v/v) containing between 0 and 956 μmol/L of Na4P2O7. The spectra were measured 10 min after each salt addition. TEM images of NP10-Zn (0.25 mg/mL) in water/methanol 1:2 (v/v) before (a) and after the

Synthesis and characterization of S,N-heterotetracenes

• Astrid Vogt,
• Florian Henne,
• Christoph Wetzel,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2020, 16, 2636–2644, doi:10.3762/bjoc.16.214

• benzofused S,N-heteroacenes 19 and 22. Supporting Information Supporting Information File 561: Synthetic procedures, 1H, 13C NMR, HRMS, and UV–vis spectra as well as cyclic voltammograms. Supporting Information File 562: Crystallographic data. Acknowledgements We gratefully acknowledge B. Müller, Institute

Anion exchange resins in phosphate form as versatile carriers for the reactions catalyzed by nucleoside phosphorylases

• Julia N. Artsemyeva,
• Ekaterina A. Remeeva,
• Tatiana N. Buravskaya,
• Irina D. Konstantinova,
• Roman S. Esipov,
• Anatoly I. Miroshnikov,
• Natalia M. Litvinko and
• Igor A. Mikhailopulo

Beilstein J. Org. Chem. 2020, 16, 2607–2622, doi:10.3762/bjoc.16.212

• ), except where otherwise indicated. TLC was performed on TLC glass plates covered with silica gel 60 F254 (Merck, Germany). The TLC control of the PF-1Pis synthesis and conversions was tested first by UV light then by heating of the plates. UV–vis spectra were recorded with a Shimadzu UV-Mini 1240

Synthesis of 4-substituted azopyridine-functionalized Ni(II)-porphyrins as molecular spin switches

• Jannis Ludwig,
• Tobias Moje,
• Fynn Röhricht and
• Rainer Herges

Beilstein J. Org. Chem. 2020, 16, 2589–2597, doi:10.3762/bjoc.16.210

• File 1. “Record player” approach for molecular spin switching. a) General principle b) Variation of the substituent R in 4-position of the pyridine unit. Record player molecules synthesized in this work (1f–j) are highlighted. Hammett plot of the investigated pyridine substituents [36]. UV–vis spectra

Water-soluble host–guest complexes between fullerenes and a sugar-functionalized tribenzotriquinacene assembling to microspheres

• Si-Yuan Liu,
• Xin-Rui Wang,
• Man-Ping Li,
• Wen-Rong Xu and
• Dietmar Kuck

Beilstein J. Org. Chem. 2020, 16, 2551–2561, doi:10.3762/bjoc.16.207

• affinity of C70-fullerene may be attributed to its larger size and surface area as compared to C60-fullerene [50]. The complexation between TBTQ-(OG)6 and fullerenes was also examined by UV–vis spectroscopy in both toluene/DMSO 1:1 (v/v) and water. Figure 3a shows the UV–vis spectra of TBTQ-(OG)6, C60 and

• NMR spectra were recorded on a 400 MHz Bruker NMR spectrometer and chemical shifts were reported in ppm (δ). The fluorescence spectra were measured on a F97Pro fluorescence spectrophotometer (LengGuang Tech, Shanghai, China) and UV–vis spectra were measured on a UV-3300PC spectrometer (Mapada

The B & B approach: Ball-milling conjugation of dextran with phenylboronic acid (PBA)-functionalized BODIPY

• Patrizia Andreozzi,
• Lorenza Tamberi,
• Elisamaria Tasca,
• Gina Elena Giacomazzo,
• Marta Martinez,
• Mirko Severi,
• Marco Marradi,
• Stefano Cicchi,
• Sergio Moya,
• Giacomo Biagiotti and
• Barbara Richichi

Beilstein J. Org. Chem. 2020, 16, 2272–2281, doi:10.3762/bjoc.16.188

• by UV–vis spectroscopy (λmax = 508–511 nm). The DMSO/ethanol mixtures and ethanol solutions were dried under vacuum, the recovered dye was solubilized in DMSO, and the UV–vis spectra were recorded. The amount of recovered PBA-BODIPY (1) was estimated (Figure 2A), using the molar extinction

• -BODIPY-dextran conjugate Dex-1b were studied in water. The UV–vis spectra of Dex-1b reported in Figure 3A shows the same absorption pattern of the PBA-BODIPY (1, see Supporting Information File 1) [26]. The main absorption band corresponding to the transition S0 → S1, is observed at λabs = 508 nm. The

• out using a glass vacuum filter with 0.2 µm sartorius. UV–vis spectra were recorded on a Varian Cary 4000 UV–vis spectrophotometer using a 1 cm cell or a BioTeK Synergy H4 microplate reader. Fluorescence spectra were registered on a Jasco FP750 spectrofluorometer using a 1 cm cell. NMR spectra were

Naphthalene diimide bis-guanidinio-carbonyl-pyrrole as a pH-switchable threading DNA intercalator

• Poulami Jana,
• Filip Šupljika,
• Carsten Schmuck and
• Ivo Piantanida

Beilstein J. Org. Chem. 2020, 16, 2201–2211, doi:10.3762/bjoc.16.185

• longer incubation times [23][26][27], the time required for reaching equilibrium was checked by repeatedly collecting UV–vis spectra of compound 4 upon the additions of DNA or RNA aliquots to the dye solution in 10 s intervals. The results showed that an incubation period of 180 s proved to be sufficient

• : s, singlet; d, doublet, m, multiplet; br, broad. MALDI–TOF mass spectra were recorded on a Bruker BioTOF III. The UV–vis spectra were recorded on a Varian Cary 100 Bio spectrophotometer and CD spectra on JASCO J815 spectrophotometer at 25 °C using appropriate 1 cm path quartz cuvettes. The

Azo-dimethylaminopyridine-functionalized Ni(II)-porphyrin as a photoswitchable nucleophilic catalyst

• Jannis Ludwig,
• Julian Helberg,
• Hendrik Zipse and
• Rainer Herges

Beilstein J. Org. Chem. 2020, 16, 2119–2126, doi:10.3762/bjoc.16.179

• ) in the PSS at 530 nm and 435 nm, determined by 1H NMR spectroscopy (600 MHz; for details, see Supporting Information File 1). a) UV–vis cuvette with a solution of porphyrin 1 (13.1 µM in THF) and the corresponding UV–vis spectra at 25 °C in the PSS at 530 nm (green) and 435 nm (blue). b) Signals of

Naphthalene diimide–amino acid conjugates as novel fluorimetric and CD probes for differentiation between ds-DNA and ds-RNA

• Annike Weißenstein,
• Myroslav O. Vysotsky,
• Ivo Piantanida and
• Frank Würthner

Beilstein J. Org. Chem. 2020, 16, 2032–2045, doi:10.3762/bjoc.16.170

• molecular ground-state electrical dipole (µ = 7.04 D), which is an evidence for an intramolecular charge transfer (CT) character of the chromophore [34]. The predicted UV–vis spectra by TD-DFT are in excellent agreement with the experimental one (Figure 3, Table 1, the vibrational coupling is neglected

• (cacodylate buffer, pH 5.0, λex = 470 nm): λmax [nm] = 573; Φfl = 0.32. Spectrophotometric studies The UV–vis spectra were recorded on a Varian Cary 100 Bio spectrophotometer or on a Jasco V670/770 spectrometer, steady state fluorescence spectra were measured on a PTI QM4/2003 or Varian Eclipse

Synthesis and properties of quinazoline-based versatile exciplex-forming compounds

• Rasa Keruckiene,
• Simona Vekteryte,
• Ervinas Urbonas,
• Matas Guzauskas,
• Eigirdas Skuodis,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101

• . The theoretical UV–vis spectra of the derivatives had single absorption bands. The band at ca. 310 nm was characterized by a combination of various transitions towards several excited states. The theoretical UV spectrum of derivative 1 had a shoulder at 390 nm. In general, the experimental UV spectra

Synthesis of esters of diaminotruxillic bis-amino acids by Pd-mediated photocycloaddition of analogs of the Kaede protein chromophore

• Esteban P. Urriolabeitia,
• Pablo Sánchez,
• Alexandra Pop,
• Cristian Silvestru,
• Eduardo Laga,
• Ana I. Jiménez and
• Carlos Cativiela

Beilstein J. Org. Chem. 2020, 16, 1111–1123, doi:10.3762/bjoc.16.98

• was obtained with 96% isolated yield. In order to understand the different reactivities of oxazolones 2 and complexes 3 towards light, the absorption UV–vis spectra of the oxazolones 2 and ortho-palladated complexes 3 (CH2Cl2, 5 × 10−4 M) were measured and this provided some clues. The positions of

• cyclobutanes 4 and reductive elimination. UV–vis spectra of 2 and 3: absorption maxima (λmax, nm). Supporting Information Supporting Information File 319: Complete experimental section; copies of NMR spectra of 2 and 3. Supporting Information File 320: Copies on NMR spectra of compounds 4 and 5

• –vis spectra of oxazolones 2 show that the absorption is zero or close to zero. Therefore, the lack of reactivity of species 2 can be related with the absence of the absorption of light. However, the ortho-palladation causes a clear bathochromic shift from compounds 2 to 3 and this results in

Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

• Nuray Altinolcek,
• Ahmet Battal,
• Mustafa Tavasli,
• William J. Peveler,
• Holly A. Yu and
• Peter J. Skabara

Beilstein J. Org. Chem. 2020, 16, 1066–1074, doi:10.3762/bjoc.16.93

• Fluorescence and Absorbance Spectrometer. Each compound (7a/7b) displayed three distinctive absorption bands in the UV–vis spectra: high energy bands and mid energy bands were assigned to π–π* and n–π* transitions, whereas the low energy bands were assigned to an intramolecular charge transfer (ICT) transition

• the compounds are given in Figure 4. Solvatochromism In general, ICT-based absorption and emission bands show solvent dependency. This is better known as solvatochromism. The ICT behaviour of compounds 7a and 7b was further investigated in different solvents. Normalised UV–vis spectra of compounds 7a

• compounds 7a and 7b in dichloromethane. Normalised UV–vis spectra of compounds 7a and 7b in different solvents. PL spectra of compounds 7a and 7b in different solvents (A–H). Synthesis of compounds 7a and 7b from carbazole 1. i) NBS, DMF, 0 °C to rt, 24 h. ii) n-hexyl bromide, TBAI, NaOH (50%), 77 °C, 8 h

Towards triptycene functionalization and triptycene-linked porphyrin arrays

• Gemma M. Locke,
• Keith J. Flanagan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2020, 16, 763–777, doi:10.3762/bjoc.16.70

• linked which, theoretically, can cause a significant energy/charge sink. Moreover, the use of π-conjugated linkers in porphyrin arrays results in significantly altered UV–vis spectra, indicating very strong electronic coupling that causes the loss of individual unit characteristics through delocalization

• fluorescence emission spectra of related dimers (Figure 8), connected via different linker groups, were taken (Figure 9 and Figure 10). Both the triptycene-linked zinc porphyrin dimer 9 and BODIPY dimer 7 were compared with a meso–meso-linked dimer 19 [50] and butadiyne-linked dimer 20 [51]. The UV–vis spectra

• triptycene-linked porphyrin dimers 9 and 16, and a triptycene-linked porphyrin monomer 14 in CHCl3 (all compounds were excited at λ = 430 nm). Compounds used for spectroscopic comparisons. UV–vis spectra of various porphyrin/BODIPY dimers with different linker groups in CHCl3. Fluorescence emission spectrum

Synthesis of C₇₀-fragment buckybowls bearing alkoxy substituents

• Yumi Yakiyama,
• Shota Hishikawa and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2020, 16, 681–690, doi:10.3762/bjoc.16.66

• hydrogen bonds (C37∙∙∙O1, C11∙∙∙O2, C40∙∙∙O4) (Figure 5c). Photophysical properties of the dialkoxides were investigated by UV–vis and emission spectroscopies (Figure 6). UV–vis spectra of 5a and 5b well reflected the electric property of 1, showing two strong bands observed at around 280–300 nm and 330

• axis and c) from the a axis. The dotted lines indicate; blue: π–π, grey: CH···π, red: CH···O interactions. In b) and c), hydrogen atoms which are not engaged in any interactions are omitted for clarity. a) UV–vis spectra and b) emission spectra of 1 and dialkoxides 5a–c. For all the spectra, the

• depths of 5b at the specific focused carbons. Supporting Information Supporting Information File 7: CIF files of compounds 5a–c. Supporting Information File 8: 1H and 13C NMR data of 3a, 3b, 4a, 4b and 5a–c, simulated UV–vis spectra of 5a, 5b and 5c. Funding This work was supported by a Grant-in-Aid

Efficient synthesis of 3,6,13,16-tetrasubstituted-tetrabenzo[a,d,j,m]coronenes by selective C–H/C–O arylations of anthraquinone derivatives

• Seiya Terai,
• Yuki Sato,
• Takuya Kochi and
• Fumitoshi Kakiuchi

Beilstein J. Org. Chem. 2020, 16, 544–550, doi:10.3762/bjoc.16.51

• the substituents in compounds 7 on their optical properties was studied by UV–vis spectroscopy (Figure 1). The UV–vis spectra of 7aa, 7bb, and 7ba were measured in chloroform, and the normalized UV–vis spectra are shown in Figure 1. These compounds showed similar peak patterns between 300 and 500 nm

Six-fold C–H borylation of hexa-peri-hexabenzocoronene

• Mai Nagase,
• Kenta Kato,
• Akiko Yagi,
• Yasutomo Segawa and
• Kenichiro Itami

Beilstein J. Org. Chem. 2020, 16, 391–397, doi:10.3762/bjoc.16.37

• 1 and Cartesian coordinates of the optimized structure of 1. Supporting Information File 101: UV–vis spectra, NMR spectra and Cartesian coordinates. Supporting Information File 102: Crystallographic information file of compound 1. Acknowledgements We thank Prof. Tsuyohiko Fujigaya (Kyushu

p-Pyridinyl oxime carbamates: synthesis, DNA binding, DNA photocleaving activity and theoretical photodegradation studies

• Panagiotis S. Gritzapis,
• Panayiotis C. Varras,
• Nikolaos-Panagiotis Andreou,
• Katerina R. Katsani,
• Konstantinos Dafnopoulos,
• George Psomas,
• Zisis V. Peitsinis,
• Alexandros E. Koumbis and
• Konstantina C. Fylaktakidou

Beilstein J. Org. Chem. 2020, 16, 337–350, doi:10.3762/bjoc.16.33

• cause of the activity. Therefore, the interaction of selected compounds, i.e., 11 and 12, with CT DNA was monitored by UV–vis spectroscopy and viscosity measurements. Additionally, the EB−displacing ability of the compounds was evaluated by fluorescence emission spectroscopy. The UV–vis spectra of a CT

• ; such changes may show the binding of the compounds to DNA which may result in the formation of a new conjugate between DNA and the compound under study [67]. The UV–vis spectra of the compounds (1 × 10−4 M) were recorded in the presence of CT DNA at increasing concentrations (diverse r’ values

• ) (Supporting Information File 1, Figure S-4.1). Both bands of the compound 11 (Supporting Information File 1, Figure S-4.1A) with λmax at 262 nm and 388 nm show hypochromism up to 14% and 2%, respectively, while for the band appearing at 271 nm a hyperchromism of 12% is observed. In the UV–vis spectra of

Potent hemithioindigo-based antimitotics photocontrol the microtubule cytoskeleton in cellulo

• Alexander Sailer,
• Franziska Ermer,
• Yvonne Kraus,
• Rebekkah Bingham,
• Ferdinand H. Lutter,
• Julia Ahlfeld and
• Oliver Thorn-Seshold

Beilstein J. Org. Chem. 2020, 16, 125–134, doi:10.3762/bjoc.16.14

• , and high-yielding synthesis of HITub-4. Chemical structures of HITubs. Key variations with respect to HITub-4 are highlighted in dashed boxes. Photocharacterisation of HITub-4. a) Photochemical and thermal isomerisation. b) UV–vis spectra after saturating illumination at λ = 450, 505, and 530 nm

The interaction between cucurbit[8]uril and baicalein and the effect on baicalein properties

• Xiaodong Zhang,
• Jun Xie,
• Zhiling Xu,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2020, 16, 71–77, doi:10.3762/bjoc.16.9

• concentrations of Q[8] were recorded (Figure 4A–C). Figure 4 shows the changes in the UV–vis spectra of BALE upon the gradual addition of Q[8]. The maximum absorption wavelength of BALE was at 270 nm and the host showed no absorbance in the range of >210 nm. The absorption spectra of the guest exhibited a

Starazo triple switches – synthesis of unsymmetrical 1,3,5-tris(arylazo)benzenes

• Andreas H. Heindl and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2020, 16, 22–31, doi:10.3762/bjoc.16.4

• and 3b showed characteristic UV–vis spectra of ABs with strong π–π* absorption, having their absorption maxima at 337 nm (3a) and 349 nm (3b), respectively (Figure 2a). In contrast to AB, the π–π* and n–π* bands of both compounds overlapped, forming shoulders at ca. 450 nm. The samples were irradiated

• switchable multistate photoswitches: previous [11][12] and present work. a) UV–vis spectra of tris(arylazo)benzenes 3a/3b in ethanol. b) Reversible photoisomerization of 3a and c) 3b using light of 365 nm wavelength to induce E→Z isomerization and of 448 nm wavelength for photochemical back-conversion

Synthesis and characterization of bis(4-amino-2-bromo-6-methoxy)azobenzene derivatives

• David Martínez-López,
• Amirhossein Babalhavaeji,
• Diego Sampedro and
• G. Andrew Woolley

Beilstein J. Org. Chem. 2019, 15, 3000–3008, doi:10.3762/bjoc.15.296

• , 2H), 4.11 (s, 6H), 3.45 (m, 8H), 3.00 (m, 8H); 13C NMR (126 MHz, DCM-d2) δ 158.9, 154.0, 140.2, 123.0, 111.5, 107.2, 66.9, 57.3, 45.1; HRMS (m/z): [M + H]+ calcd for C22H29Br2N6O2, 567.0719; found, 567.0713. UV–vis spectroscopy UV–vis spectra were recorded on a PerkinElmer LAMBDA 35, Shimadzu UV

• experiments. Estimates of the percentage of cis/trans isomers in PSSs Based on NMR spectra, we assumed that the fraction of Z-isomer present at equilibrium in the dark was negligible. Since UV–vis spectra obtained during thermal reversion exhibited an isosbestic point, we assumed that only E- and Z-isomers

• subjected to TD-SCF calculations using the same functionals and basis set, assuming the first 15 singlet excitations, and by applying a SMD (assuming water as the solvent) to implicitly approximate the effect of the solvent [29]. TD-SCF data were used to generate the simulated UV–vis spectra by applying a

Chemical tuning of photoswitchable azobenzenes: a photopharmacological case study using nicotinic transmission

• Lorenzo Sansalone,
• Jun Zhao,
• Matthew T. Richers and
• Graham C. R. Ellis-Davies

Beilstein J. Org. Chem. 2019, 15, 2812–2821, doi:10.3762/bjoc.15.274

• Supporting Information File 1. Absorption spectroscopy UV–vis spectra were recorded using a Cary 50 spectrophotometer (Agilent, Santa Clara, CA, USA) at rt in quartz cuvettes with a 1 cm path length in HEPES buffer at pH 7.4. UPLC Chromatography was performed using a Waters Acuity Arc using Cortecs C-18

Skeletocutins M–Q: biologically active compounds from the fruiting bodies of the basidiomycete Skeletocutis sp. collected in Africa

• Tian Cheng,
• Clara Chepkirui,
• Cony Decock,
• Josphat C. Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2782–2789, doi:10.3762/bjoc.15.270

• range: 100–2500 m/z, capillary voltage: 4500 V, drying temperature: 200 °C). UV–vis spectra were recorded with a Shimadzu UV-2450 UV–vis spectrophotometer. The chromatogram in Figure 1 was recorded on a Bruker Agilent 1260 Infinity Series equipped with DAD and an ESI ion trap mass spectrometer (amaZon