Pyrene–nucleobase conjugates: synthesis, oligonucleotide binding and confocal bioimaging studies

• Artur Jabłoński,
• Yannic Fritz,
• Hans-Achim Wagenknecht,
• Rafał Czerwieniec,
• Tytus Bernaś,
• Damian Trzybiński,
• Krzysztof Woźniak and
• Konrad Kowalski

Beilstein J. Org. Chem. 2017, 13, 2521–2534, doi:10.3762/bjoc.13.249

• nucleoli. Noticeably, this pattern was not observed when the cells were labeled with 4. On the other hand fluorescence emission spectra of both compounds in cells were similar (Figure S7, Supporting Information File 1) and compatible with their counterparts registered in dichloromethane solution. This

Synthesis and photophysical properties of novel benzophospholo[3,2-b]indole derivatives

• Mio Matsumura,
• Mizuki Yamada,
• Atsuya Muranaka,
• Misae Kanai,
• Naoki Kakusawa,
• Daisuke Hashizume,
• Masanobu Uchiyama and
• Shuji Yasuike

Beilstein J. Org. Chem. 2017, 13, 2304–2309, doi:10.3762/bjoc.13.226

• = 75%) was high, comparable to that of phosphole and indole-fused pentacyclic heteroacene (Ф = 70%) [35]. On the other hand, a low fluorescence intensity was observed for phosphine sulfide 5 and selenide 6 (Ф = 1% and 0.3%, respectively). Quenching of fluorescence emission due to a soft sulfur

• phospholium salt, and the borane complex showed a high fluorescence emission. Further investigations are underway to develop functional materials including electronic devices and evaluate the physicochemical properties of these compounds by synthetic, theoretical, and spectroscopic studies. Phosphole-based

• tetracyclic heteroacenes. ORTEP drawing of compound 3 (left) and 4 (right) with 50% probability. All hydrogen atoms are omitted for clarity. One of two geometries in the unit cell was drawn for 4. UV–vis absorption (left) and normalized fluorescence emission (right, excitation at 335 nm) spectra in CH2Cl2

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

• derivatization of mycolactone A/B (1a,b) with a 2-naphthylboronate-based fluorogenic chemosensor (Figure 4). The latter complexes the 1,3-diol moiety proximal to the pentaene motif of the lower side chain, thus resulting in enhanced fluorescence emission intensity of the mycolactone band upon irradiation with

BODIPY-based fluorescent liposomes with sesquiterpene lactone trilobolide

• Ludmila Škorpilová,
• Silvie Rimpelová,
• Michal Jurášek,
• Miloš Buděšínský,
• Jana Lokajová,
• Roman Effenberg,
• Petr Slepička,
• Tomáš Ruml,
• Eva Kmoníčková,
• Pavel B. Drašar and
• Zdeněk Wimmer

Beilstein J. Org. Chem. 2017, 13, 1316–1324, doi:10.3762/bjoc.13.128

• -terminated intermediate 5 in excellent yield (92%). Finally, CuAAC cycloadition of 5 and Tb-N3VA [31] gave the target fluorescent construct 6 in good yield (84%). The absorbance and fluorescence emission spectra of compounds 3–6 are depicted in Figure 2. Compounds 3–6 showed absorption and emission maxima at

Fluorescent carbon dots from mono- and polysaccharides: synthesis, properties and applications

• Stephen Hill and
• M. Carmen Galan

Beilstein J. Org. Chem. 2017, 13, 675–693, doi:10.3762/bjoc.13.67

• autoclave chamber with heating to 200 °C for 12 h (Scheme 3) [29]. The fluorescence emission could be tuned by changing the ratio of sugar and KH2PO4. For instance a molar ratio of 1:26 (glucose/KH2PO4) afforded blue-fluorescent CDs (QY = 0.02), whereas a 1:36 ratio yielded green-fluorescent CDs (QY = 0.01

• crystallinity with blue-green emission. Most reported CD syntheses, regardless of the type of starting material or synthetic method, tend to produce CDs with blue-green fluorescence emission. Jana et al. reported a carbohydrate-based preparation to access yellow and red emissive CDs, demonstrating that fine

Novel β-cyclodextrin–eosin conjugates

• Gábor Benkovics,
• Damien Afonso,
• András Darcsi,
• Szabolcs Béni,
• Sabrina Conoci,
• Éva Fenyvesi,
• Lajos Szente,
• Milo Malanga and
• Salvatore Sortino

Beilstein J. Org. Chem. 2017, 13, 543–551, doi:10.3762/bjoc.13.52

• spectroscopic investigations on the conjugates were carried out in aqueous solutions. Figure 6 shows the absorption and fluorescence emission spectra of eosin Y conjugate 2–β-CD and, for comparison, of the free dye 2. Apart from a slight red shift of the absorption maximum, the absorption spectral profile in

• the visible region of the conjugate is similar to that of the free dye, ruling out any relevant aggregation phenomena. This hypothesis was well confirmed by the fluorescence emission spectrum, which exhibits an intense band maximum at 550 nm. The fluorescence quantum yield was Φf = 0.20, which is very

• corresponding 4–β-CD conjugate did not show either detectable fluorescence emission or 1O2 photogeneration. This is not surprising in light of the observed massive aggregation of this derivative in aqueous medium (see Figure 5). Studies currently in progress are addressed to better clarify this point and to

Benzothiadiazole oligoene fatty acids: fluorescent dyes with large Stokes shifts

• Lukas J. Patalag and
• Daniel B. Werz

Beilstein J. Org. Chem. 2016, 12, 2739–2747, doi:10.3762/bjoc.12.270

• C27H38N2O2SNa+, 477.25462; found, 477.25542. Examples for previously prepared fluorescent fatty acids and our present work. Absorption spectra of fatty acids 3, 7 and 11. Solid lines show the UV absorption while dashed lines show fluorescence emission. Excitation was performed at the longest wavelength in each

A self-assembled cyclodextrin nanocarrier for photoreactive squaraine

• Ulrike Kauscher and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2016, 12, 2535–2542, doi:10.3762/bjoc.12.248

• constant of AdSq with the cyclodextrins in the CDV could be obtained by plotting the maximum fluorescence emission (at 676 nm) against the concentration of available cyclodextrin (Figure 3, bottom). The resulting Langmuir isotherm was fitted by linear regression (see Supporting Information File 1 for

High performance p-type molecular electron donors for OPV applications via alkylthiophene catenation chromophore extension

• Paul B. Geraghty,
• Calvin Lee,
• Jegadesan Subbiah,
• Wallace W. H. Wong,
• James L. Banal,
• Mohammed A. Jameel,
• Trevor A. Smith and
• David J. Jones

Beilstein J. Org. Chem. 2016, 12, 2298–2314, doi:10.3762/bjoc.12.223

• evident that subtle changes in molecular orientation and packing, with a tendency to H-aggregate formation, are present, however, further work is being undertaken to better understand the underlying processes leading to these changes. Fluorescence emission spectra were collected using the same films as

• temperatures (Figure 10) but there is no appearance of the new shoulder, however as the films are rapidly cooled there may be a kinetic effect (see below). Variable temperature fluorescence emission spectra were recorded on BTR and BQR (Figure 9) using a similar setup as for the UV–vis measurements (Figure 8

• remain unclear and are the subject of further structural studies on BTR and BQR thin films. The appearance of the second fluorescence emission peak in variable temperature spectra on the POM stage, again not seen on the thin films (Figure 7c), has been examined in more detail. The thin films used to

Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines

• David R. Chisholm,
• Garr-Layy Zhou,
• Ehmke Pohl,
• Roy Valentine and
• Andrew Whiting

Beilstein J. Org. Chem. 2016, 12, 1851–1862, doi:10.3762/bjoc.12.174

• CARY100 UV–visible spectrophotometer using the Cary WinUV Scan software 3.00(182). Fluorescence emission spectroscopy was conducted using a Perkin Elmer LS 55 fluorescence spectrometer. All in situ FTIR spectroscopy experiments (ReactIR, Mettler Toledo) were carried out using a ReactIR 15 with MCT

Synthesis and properties of fluorescent 4′-azulenyl-functionalized 2,2′:6′,2″-terpyridines

• Adrian E. Ion,
• Liliana Cristian,
• Mariana Voicescu,
• Masroor Bangesh,
• Augustin M. Madalan,
• Daniela Bala,
• Constantin Mihailciuc and
• Simona Nica

Beilstein J. Org. Chem. 2016, 12, 1812–1825, doi:10.3762/bjoc.12.171

• origin of the fluorescence emission will be also described by time-dependent density functional theory (TDDFT) calculations. The ability of the terpyridine compounds to bind poisoning metal cations was investigated by spectrophotometric titrations of methanolic 4′-azulenyl-substituted terpyridine

• spectroscopy in dichloromethane solution. The 2,2′:6′,2″-terpyridine moiety is an excellent chromophore with an absorption maximum at 279 in dichloromethane solution [8]. Upon 4′-substitution with a phenyl group the longest-wavelength absorption is not affected, only the fluorescence emission is shifted

• absorption maximum. Both compounds showed fluorescent emission upon excitation at wavelengths corresponding to their absorption maximum. The fluorescence spectra are shown in Figure 5. In the case of 4a, by excitation with 375 nm, a dual fluorescence emission is observed at 435 nm and 530 nm, respectively

Amidofluorene-appended lower rim 1,3-diconjugate of calix[4]arene: synthesis, characterization and highly selective sensor for Cu²⁺

• Rahman Hosseinzadeh,
• Mohammad Nemati,
• Reza Zadmard and
• Maryam Mohadjerani

Beilstein J. Org. Chem. 2016, 12, 1749–1757, doi:10.3762/bjoc.12.163

• indicates that the L binds copper as Cu2+. Fluorescence titrations of L with metal ions Fluorescence spectroscopy was applied to investigate the recognition properties of chemosensor L toward various metal ions in MeCN. In the absence of metal ions, the receptor L represents fluorescence emission at ≈365 nm

• +, Co2+, Ni2+, Cd2+, Ag+, Ba2+, K+, Na+ and Li+. The fluorescence spectra showed almost no obvious change relative to the free ligand L (Figure 4). Titration of L with Cu2+ resulted in a gradual quenching of the fluorescence emission at the 365 nm band as a function of increasing Cu2+ concentration. The

• the competitive recognition of Cu2+ by sensor L, the effect of Cu2+ was studied in the presence of other metal ions. The results showed that the fluorescence emission intensity of [L + Mn+] is altered in the presence of Cu2+ ions (Figure 6). It is noteworthy that complex [L + Mn+] exhibited no

Application of Cu(I)-catalyzed azide–alkyne cycloaddition for the design and synthesis of sequence specific probes targeting double-stranded DNA

• Svetlana V. Vasilyeva,
• Vyacheslav V. Filichev and
• Alexandre S. Boutorine

Beilstein J. Org. Chem. 2016, 12, 1348–1360, doi:10.3762/bjoc.12.128

• interaction of the F1-NH2-TO probe with the target duplex. To test the specificity of these probes we titrated them with a non-target duplex that resulted in a 1.5 times increase in fluorescence emission for the MM14 probe and also 8 times increase for the F1-NH2-TO probe (Figure 8). The non-specific increase

• absorption spectra in the interval 300–700 nm do not change upon DNA titration (data not shown), which means that increase in fluorescence emission is due to the increase of the quantum yield of fluorescence. Studies of interaction of the probes with fixed and live mouse cells are under investigation in the

Synthesis, fluorescence properties and the promising cytotoxicity of pyrene–derived aminophosphonates

• Jarosław Lewkowski,
• Maria Rodriguez Moya,
• Anna Wrona-Piotrowicz,
• Janusz Zakrzewski,
• Renata Kontek and
• Gabriela Gajek

Beilstein J. Org. Chem. 2016, 12, 1229–1235, doi:10.3762/bjoc.12.117

• preliminary form [9], fluorescence emission of their azomethine precursors was reported for pyrene-1-carboxaldehyde thiosemicarbazone and Schiff bases as well as their metal complexes [16][17][18][19][20][21]. Such properties were described for, e.g., ruthenium(II) complexes of (5-chloropyridin-2-yl)-(pyren-1

Self and directed assembly: people and molecules

• Tony D. James

Beilstein J. Org. Chem. 2016, 12, 391–405, doi:10.3762/bjoc.12.42

• ] + [R] = 5.0 × 10−6 mol dm−3; λem at 358 nm. Reproduced with permission from [61]. Copyright 2004 John Wiley and Sons. Chiral discriminating sensor (relative stereochemistry shown) constructed using a good fluorophore (anthracene). Fluorescence emission intensity-pH profile of: (a) Sensor 15: 1.0 × 10−6

Friedel–Crafts-type reaction of pyrene with diethyl 1-(isothiocyanato)alkylphosphonates. Efficient synthesis of highly fluorescent diethyl 1-(pyrene-1-carboxamido)alkylphosphonates and 1-(pyrene-1-carboxamido)methylphosphonic acid

• Anna Wrona-Piotrowicz,
• Janusz Zakrzewski,
• Anna Gajda,
• Tadeusz Gajda,
• Anna Makal,
• Arnaud Brosseau and
• Rémi Métivier

Beilstein J. Org. Chem. 2015, 11, 2451–2458, doi:10.3762/bjoc.11.266

• isolated in 87% yield. Photophysical properties of 3a–d and 4 As expected, thioamides 2a–d were nonfluorescent (thioamide group is a well-known fluorescence quencher [31]). In contrast, the corresponding amides 3a–d showed strong fluorescence emission in solution and in the solid state. We studied the

2-Hetaryl-1,3-tropolones based on five-membered nitrogen heterocycles: synthesis, structure and properties

• Yury A. Sayapin,
• Inna O. Tupaeva,
• Alexandra A. Kolodina,
• Eugeny A. Gusakov,
• Vitaly N. Komissarov,
• Igor V. Dorogan,
• Nadezhda I. Makarova,
• Anatoly V. Metelitsa,
• Valery V. Tkachev,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2015, 11, 2179–2188, doi:10.3762/bjoc.11.236

• ); selected bond angles (o) N(1)–C(8)–O(1) 114.99(9), O(1)–C(8)–C(2) 119.76(8), N(1)–C(8)–C(2) 125.24(9), C(3)–C(2)–C(8) 117.85(8), C(1)–C(2)–C(8) 122.45(9). Electronic absorption (1, 2), fluorescence emission (λexc = 350 nm) (3, 4) and fluorescence excitation [λobs = 495 nm (5), λobs = 510 nm (6)] spectra of

Fluoride-driven ‘turn on’ ESPT in the binding with a novel benzimidazole-based sensor

• Kai Liu,
• Xiaojun Zhao,
• Qingxiang Liu,
• Jianzhong Huo,
• Bolin Zhu and
• Shihua Diao

Beilstein J. Org. Chem. 2015, 11, 563–567, doi:10.3762/bjoc.11.61

• -mentioned proton in BIP. To further explore the photophysical sensing properties of BIP with various anions (F−, Cl−, Br−, I−, H2PO4−, NO3−, AcO−, added as TBA salts), fluorescence measurements were carried out. The weak fluorescence emission at 411 nm, corresponding to the enol form of a Schiff base [32

• fluorescence emission hardly experienced any perturbation on adding a similar amount of anions as done with F−. Also, the detection of F− displayed no interference in presence of other competitive anions (See Figure S7 in Supporting Information File 1). This demonstrated BIP has a high selectivity for F−. The

Synthesis and surface grafting of a β-cyclodextrin dimer facilitating cooperative inclusion of 2,6-ANS

• Lars W. Städe,
• Thorbjørn T. Nielsen,
• Laurent Duroux,
• Reinhard Wimmer,
• Kyoko Shimizu and
• Kim L. Larsen

Beilstein J. Org. Chem. 2015, 11, 514–523, doi:10.3762/bjoc.11.58

• stability compared to that of parent β-CD. The potential conformations for 1:1 complexes of the β-CD dimer with 2,6-ANS are illustrated in Figure 3. Figure 4a shows the fluorescence emission spectra of 50 µM 2,6-ANS (solid grey) in phosphate-buffered saline (PBS, pH 7.4) and 50 µM 2,6-ANS in PBS with 2 mM β

• eventually be further stabilized by hydrogen bonding, involving rim hydroxy groups from both cavities and the amino function. The binding mechanism suggested on the basis of the changes in fluorescence emission is confirmed by the NMR ROESY spectrum of the β-CD dimer/2,6-ANS inclusion complex (Figure 5). Due

• employing the sensitive surface technique, TIRF spectroscopy. This technique allows for monitoring of surface binding events within ≈200 nm of an optical transparent substrate. Figure 7a shows the fluorescence emission spectra after injection of 1 mM 2,6-ANS in PBS (grey) on a bare quartz slide and quartz

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

• the PAE 10b with an additional acetylene fragment differed from the absorption spectrum of the PAE 10a by a small bathochromic shift (≈7 nm) of two absorption bands and an additional absorption band at 266 nm (Figure 6). The fluorescence emission spectra of the same solutions (Figure 7) were recorded

• + and are not related to the hydrochloric acid which was essential for the preparation of an aqueous solutions of PdCl2, the influence of HCl on the optical properties of the oligomer 10a was studied. The obtained data revealed that changes in the absorption and fluorescence emission spectra for the PAE

• 10a under 10-fold excess of HCl are opposite to the ones induced by Pd2+ ions. Thus instead of a "red" shift of absorption bands and the fluorescence quenching, a slight "blue" shift and the increase in the fluorescence emission were observed (Figure 12 and Figure 13). The additional evidence for the

Formation of nanoparticles by cooperative inclusion between (S)-camptothecin-modified dextrans and β-cyclodextrin polymers

• Thorbjørn Terndrup Nielsen,
• Catherine Amiel,
• Laurent Duroux,
• Kim Lambertsen Larsen,
• Lars Wagner Städe,
• Reinhard Wimmer and
• Véronique Wintgens

Beilstein J. Org. Chem. 2015, 11, 147–154, doi:10.3762/bjoc.11.14

• fitted with a theoretical titration curve using the instrument software, assuming a 1:1 complex. The enthalpy change, ΔH, the binding constant (K), and the stoichiometry (n), were the adjustable parameters. Fluorescence emission spectra were recorded on Varian Cary Eclipse fluorescence spectrophotometer

• as a function of time and integrated heat vs the molar ratio (enthalpogram). Fluorescence emission spectra of a) D70GPCPT and b) D10GPCPT recorded at different concentrations (0–2 mM β-CD) of D70HPβ-CD. The dotted line in a) is the emission spectra of the D70GPCPT polymer with 2 mM of free β-CD. The

Come-back of phenanthridine and phenanthridinium derivatives in the 21st century

• Lidija-Marija Tumir,
• Marijana Radić Stojković and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2930–2954, doi:10.3762/bjoc.10.312

• phenanthridinium relative to the unmodified primary amino groups. Namely, derivatives of EB having substituents with weaker electron-donor properties exhibited a stronger fluorescence emission than EB, while a stronger electron-donating substituent exhibited a much lower fluorescence emission. Such behaviour could

• phenanthridine–thymine conjugates [77], intercalated into ds-DNA whereby binding was marginally influenced by attached thymine and the peptide backbone. More intriguing was the observed excimer fluorescence emission and the very specific CD spectrum of pentapeptide confirming the very efficient phenanthridine

• of the phenanthridine/phenanthridinium system for chemical and biochemical research. Widely used fluorimetric dyes, such as cyanine derivatives, are non-fluorescent in the free state but give tremendous fluorescence emission upon binding to biomacromolecular targets. However, many of these dyes show

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

• in 2002 by Lezcano et al. [36]. Phase solubility and fluorescence emission spectra of the carbendazim in the presence of different CD concentrations have been applied to characterize the inclusion complexes. In each case, 1:1 inclusion complexes were observed between carbendazim and CD. However, the

Synthesis and optical properties of pyrrolidinyl peptide nucleic acid carrying a clicked Nile red label

• Nattawut Yotapan,
• Chayan Charoenpakdee,
• Pawinee Wathanathavorn,
• Boonsong Ditmangklo,
• Hans-Achim Wagenknecht and
• Tirayut Vilaivan

Beilstein J. Org. Chem. 2014, 10, 2166–2174, doi:10.3762/bjoc.10.224

• purification. All Nile red-labeled acpcPNAs are freely soluble in water (>1 mM), providing a bright blue solution. The UV–vis spectrum of the free propargyl Nile red label 1 in acetonitrile (Figure 2a) showed absorption and fluorescence emission maxima at 538 nm and 620 nm, with a fluorescence quantum yield

• the fluorescence quantum yields (50% MeCN: λabs 564 nm, λem 641 nm, ΦF 0.29; 20% MeCN: λabs 587 nm, λem 651 nm; ΦF 0.14). In aqueous phosphate buffer (10 mM, pH 7.0), the Nile red-labeled acpcPNA 10mer-Nr exhibited a broad absorption peak centered at 575 nm and a fluorescence emission at 656 nm

• , respectively (Figure 2b). The solvatochromic property of the Nile red-labeled acpcPNA is demonstrated as shown by the progressively blue-shifted absorption and fluorescence emission maxima in the presence of acetonitrile (100% MeCN: λabs 544 nm, λem 634 nm; 50% MeCN: λabs 569 nm, λem 647 nm; 20% MeCN: λabs 592

The effect of permodified cyclodextrins encapsulation on the photophysical properties of a polyfluorene with randomly distributed electron-donor and rotaxane electron-acceptor units

• Aurica Farcas,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert,
• Flavian Farcas,
• Iuliana Stoica and
• Anton Airinei

Beilstein J. Org. Chem. 2014, 10, 2145–2156, doi:10.3762/bjoc.10.222

• the lower aggregation tendency [13]. The determined absorption onset wavelength of 4, 4a and 4b copolymer films are 429, 430 and 427 nm, which gives rise to the corresponding optical band gaps (Eopt = 1240/λonset) [38], of 2.89, 2.88 and 2.90 eV, respectively Table 2. The fluorescence emission (PL) of

• . Termogravimetric curves (TG) of the copolymers. DSC traces on second heating scan of 4 (a), 4a (b) and 4b (c). Optical absorption spectra of the copolymers in DCM solutions (c = 1.5∙10−6 mg∙mL−1) (a) and thin films (b). Fluorescence emission spectra of the copolymers in DCM solutions (c = 1.5∙10−6 mg∙mL−1) (a) and