Probing of local polarity in poly(methyl methacrylate) with the charge transfer transition in Nile red

• Aydan Yadigarli,
• Qimeng Song,
• Sergey I. Druzhinin and
• Holger Schönherr

Beilstein J. Org. Chem. 2019, 15, 2552–2562, doi:10.3762/bjoc.15.248

• particular, the spatial distribution of the dielectric constant measured for thin PMMA films was described using NR as a reported dye [15]. Because NR is (i) a photostable dye, (ii) possesses convenient optical properties, such as excitation with visible light, and fluorescence, which does not overlay with

Mono- and bithiophene-substituted diarylethene photoswitches with emissive open or closed forms

• A. Lennart Schleper,
• Mariano L. Bossi,
• Vladimir N. Belov and
• Stefan W. Hell

Beilstein J. Org. Chem. 2019, 15, 2344–2354, doi:10.3762/bjoc.15.227

• ]thiophene core. The structures of “thiophenylated” DAEs AsTh1, AsTh2, SyTh1, SyTh2, AsOTh1, AsOTh2, SyOTh1, and SyOTh2 prepared and studied in this work are given in Figure 1. Methyl esters of the thiophene carboxylic acids were chosen as model building blocks, because they possess optical properties

• the same on/off behavior. Conclusion We prepared eight 1,2-bis[(2-ethylbenzo[b]thiophene)-3-yl]perfluorocyclopentenes with oxidized and nonoxidized cores and decorated them with mono- and bithiophene rings in symmetric and asymmetric fashions. By studying the optical properties of the new compounds

• atmosphere, an emulsion of the starting compounds, Pd2(dba)3, P(Cy)3 stock solution, and aqueous K2CO3 in THF (see Supporting Information File 1 for details). Saponification of methyl ester groups in tetraester SyTh2 leading to tetracarboxylic acid SyTh2-H. Optical properties of the photochromic DAEs (in

Synthesis of a dihalogenated pyridinyl silicon rhodamine for mitochondrial imaging by a halogen dance rearrangement

• Jessica Matthias,
• Thines Kanagasundaram,
• Klaus Kopka and
• Carsten S. Kramer

Beilstein J. Org. Chem. 2019, 15, 2333–2343, doi:10.3762/bjoc.15.226

• optical properties for medical and bioimaging. As a compound with intrinsic mitochondria targeting ability, the radiolabelled analogue can be applied in multimodal (PET/OI) imaging of mitochondria for diagnostic and therapeutic use in, e.g., cancer patients. Keywords: halogen-dance reaction

• features with their optical properties and control the latter by rational dye design [15][24][25][26]. These investigations led to new silicon rhodamine dyes with enhanced and fine-tuned properties (quantum yield, lifetime, brightness, absorption and emission maxima). A recent review compared the

• HD reactions of nicotinic acids can be found in the literature. In fact, if 2,3-dihalogenated pyridines are used for the HD rearrangement as starting materials, only methyl groups are tolerated as carbon substituents. Optical properties of the pyridinyl silicon rhodamine 15 The dihalogenated

Synthesis and properties of sulfur-functionalized triarylmethylium, acridinium and triangulenium dyes

• Marco Santella,
• Eduardo Della Pia,
• Jakob Kryger Sørensen and
• Bo W. Laursen

Beilstein J. Org. Chem. 2019, 15, 2133–2141, doi:10.3762/bjoc.15.210

• functionalities were synthesized and their optical properties were studied. The sulfur functionalities were introduced by aromatic nucleophilic substitution of methoxy groups in triarylmethylium cations with ethanethiol followed by partial or full ring closure of the ortho positions with nitrogen or oxygen

• + PF6− (6) and the mono ring closed xanthenium 7. Synthesis of S2-TOTA+ PF6− (8) and S1-TOTA+ PF6− (9). Summary of absorption data of triarylmethylium ions in MeCN. Summary of absorption data of substituted TOTA dyes in CH2Cl2. Summary of optical properties of the fluorescent derivatives. Supporting

Naphthalene diimides with improved solubility for visible light photoredox catalysis

• Barbara Reiß and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2019, 15, 2043–2051, doi:10.3762/bjoc.15.201

• have only little influence on the optical properties but significantly modulate the solubility in DMF. This result agrees with other cNDIs in literature [47][48][58]. NDI 1 shows weak fluorescence in CH2Cl2 with a maximum at 384 nm and a quantum yield of 7%. The Stokes’ shift is small (413 cm−1). Based

• photoredox catalyst improve the sustainability and make photoredox catalysis “greener”. Experimental All experimental details are described in the Supporting Information File 1. Optical properties of NDI 1 and cNDIs 2 and 6: UV–vis absorbance in CH2Cl2 and in DMF (normal lines), normalized fluorescence in

Tautomerism as primary signaling mechanism in metal sensing: the case of amide group

• Vera Deneva,
• Georgi Dobrikov,
• Aurelien Crochet,
• Daniela Nedeltcheva,
• Katharina M. Fromm and
• Liudmil Antonov

Beilstein J. Org. Chem. 2019, 15, 1898–1906, doi:10.3762/bjoc.15.185

• development of natural ligand-supported metal investigations. The ion recognition is based on the existence of two molecular states (ligand and complex) with different optical properties and a structure that allows fast transfer from the ligand to the complex upon addition of the desired metal ion [7]. The

Identification of optimal fluorescent probes for G-quadruplex nucleic acids through systematic exploration of mono- and distyryl dye libraries

• Xiao Xie,
• Michela Zuffo,
• Marie-Paule Teulade-Fichou and
• Anton Granzhan

Beilstein J. Org. Chem. 2019, 15, 1872–1889, doi:10.3762/bjoc.15.183

• cationic dyes was synthesized and investigated with respect to their optical properties, propensity to aggregation in aqueous medium, and capacity to serve as fluorescence “light-up” probes for G-quadruplex (G4) DNA and RNA structures. Among the 61 compounds, 57 dyes showed preferential enhancement of

• , sufficiently soluble in the aqueous buffer. All dyes were rigorously purified by recrystallization and their identity and purity were confirmed by 1H and 13C NMR, LC–MS and elemental analysis data. Optical properties The library of styryl dyes covers a broad spectral range, with absorption maxima ranging, in

•  4B). On the other hand, the nature of the substituent R in the 2,4-pyridinium unit has only a minor influence on the optical properties, and the absorption bands of the dyes 2a–6a are only slightly red-shifted (by 10–20 nm in MeOH) with respect to that of 1a. Fluorimetric response of dyes towards DNA

A golden opportunity: benzofuranone modifications of aurones and their influence on optical properties, toxicity, and potential as dyes

• Joza Schmitt and
• Scott T. Handy

Beilstein J. Org. Chem. 2019, 15, 1781–1785, doi:10.3762/bjoc.15.171

• of snapdragons and cosmos. Most studies of aurones focus on their range of biological activities, but relatively little has been reported with respect to their optical properties, unlike their aza and thio analogs. What little is known has focused entirely on the influence of the benzylidene portion

• virtually the entirety of recorded history and yet the application of aurones as dyes or pigments has not been reported or studied [3]. Even the optical properties of aurones have had very minimal study. The reports that have appeared have all focused on fluorescent properties and have also been largely

• system, we chose to study the potential for aurones to be used as dyes as well as a more extensive study of the impact of substitution in the benzofuranone portion of the molecule on its optical properties. Results and Discussion Synthesis We have previously reported the synthesis of a significant number

Functional panchromatic BODIPY dyes with near-infrared absorption: design, synthesis, characterization and use in dye-sensitized solar cells

• Quentin Huaulmé,
• Cyril Aumaitre,
• Outi Vilhelmiina Kontkanen,
• David Beljonne,
• Alexandra Sutter,
• Gilles Ulrich,
• Renaud Demadrille and
• Nicolas Leclerc

Beilstein J. Org. Chem. 2019, 15, 1758–1768, doi:10.3762/bjoc.15.169

• high stability in various media. More importantly, they display a very versatile chemistry, allowing the fine tuning of all their physical and optical properties [14]. They hence have found applications in various fields, such as lasers dyes [15], (bio)-labeling [16][17], photodynamic therapy [18], or

• BODIPY derivative, we decided to synthetize the two molecular structures disclosed in Figure 1, namely BOD-TTPA-alk and BOD-TTPA. To support our molecular design, and especially to have better insight on the electronic structure and optical properties of the dyes, we performed (time-dependent) density

• dehalogenation side-product. Finally, a Knoevenagel condensation in the presence of cyanoacetic acid and piperidine is performed to lead to the targeted compounds BOD-TTPA-alk and BOD-TTPA. 3. Optical properties The optical properties of compounds BOD-TTPA-alk and BOD-TTPA were first evaluated in diluted (≈10−6

Synthesis, photophysical and electrochemical properties of pyridine, pyrazine and triazine-based (D–π–)₂A fluorescent dyes

• Keiichi Imato,
• Toshiaki Enoki,
• Koji Uenaka and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2019, 15, 1712–1721, doi:10.3762/bjoc.15.167

• were prepared by Stille coupling of stannyl compound 1 [3] with 3,5-dibromopyridine, 2,6-diiodopyrazine, and 2,4-dichloro-1,3,5-triazine, respectively (Scheme 1; see Experimental section for the synthetic procedure of OUJ-2). Optical properties The photoabsorption and fluorescence spectra of OUY-2, OUK

Synthesis, enantioseparation and photophysical properties of planar-chiral pillar[5]arene derivatives bearing fluorophore fragments

• Guojuan Li,
• Chunying Fan,
• Guo Cheng,
• Wanhua Wu and
• Cheng Yang

Beilstein J. Org. Chem. 2019, 15, 1601–1611, doi:10.3762/bjoc.15.164

• triplet–triplet annihilation upconversion. Optical properties Due to the fact that the Py and DPA units are too large to enter the cavity of the pillar[5]arene, we expected that the oxygen-through-annulus rotation is blocked in P5A-DPA and P5A-Py, giving rise to two pairs of enantiomeric pillar[5]arene

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

• , shape and chemical environment giving rise to different SPR band wavelengths [6][7][8]. Especially gold nanorods (AuNR) are of interest because of their good synthetic availability and their unique optical properties. Due to their anisotropy AuNR possess a transversal SPR (TSPR) band in the visible and

Selenophene-containing heterotriacenes by a C–Se coupling/cyclization reaction

• Pierre-Olivier Schwartz,
• Sebastian Förtsch,
• Astrid Vogt,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2019, 15, 1379–1393, doi:10.3762/bjoc.15.138

• [3,2-b]selenophene [21][22] and selenolo[3,2-b]selenophene [23], were described and represent analogues to the well-known thieno[3,2-b]thiophene [24]. Three fused selenophenes only were implemented in larger heteroacenes and analyzed towards their optical properties [25] whereupon the unsubstituted

• properties The optical properties of the four heterotriacenes were investigated by UV–vis and fluorescence spectroscopy in dichloromethane solution (Figure 6, left and Table 4). The absorption spectra in the series of DTT 1 to DSS 4 showed one main absorption band exhibiting vibronic fine structure according

• as electrolyte and the redox and optical properties of the obtained films were determined. Electropolymer P(DTT) P1 has already been reported in literature and the findings agree well with our results [46][51]. In Figure 8, exemplarily the electropolymerization of heterotriacene DST 2 (left) and

Synthesis of dipolar molecular rotors as linkers for metal-organic frameworks

• Sebastian Hamer,
• Fynn Röhricht,
• Marius Jakoby,
• Ian A. Howard,
• Xianghui Zhang,
• Christian Näther and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1331–1338, doi:10.3762/bjoc.15.132

• available in gram amounts for the synthesis of MOF or SURMOF structures with promising electric and optical properties. Interactions of a pair of dipolar rotors in different orientations. The axes of the rotors are parallel at a distance of 10 Å (terminal H atoms at the ethynyl units are in a plane and at

Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines

• Andrejs Šišuļins,
• Jonas Bucevičius,
• Yu-Ting Tseng,
• Irina Novosjolova,
• Kaspars Traskovskis,
• Ērika Bizdēna,
• Huan-Tsung Chang,
• Sigitas Tumkevičius and
• Māris Turks

Beilstein J. Org. Chem. 2019, 15, 474–489, doi:10.3762/bjoc.15.41

• The optical properties of the synthesized compounds were assessed by performing absorption and fluorescence spectroscopy and fluorescence quantum yield measurements. The quantum yields were determined using a fluorescence standard of quinine sulfate in 0.1 M H2SO4 as a reference [53]. Absorption and

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

• transparent, homogeneous and clear, indicative of their similarities in structure. Based on the above analyses and comparison with the data in literatures [54][55], it is concluded that the 1-R cubanes have been successfully fabricated. Next, to investigate the effect of different ligands on the optical

• 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

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

• for applications as data storage devices [83] or molecular logic gates [84]. Besides simple molecular electrochromic switches, complex TTF-based MIMs with unique optical properties have been constructed. In 2012, rotaxane 18 with a structure similar to previously reported donor–acceptor rotaxanes was

• , DFT calculations, and UV–vis spectroscopy confirmed five different redox states (TTF/NDI, TTF●+/NDI, TTF2+/NDI, TTF/NDI●−, TTF/NDI2−) and shows interesting optical properties in each of these redox states making this type of mechanically constrained donor–acceptor complex very interesting for

Rational design of boron-dipyrromethene (BODIPY) reporter dyes for cucurbit[7]uril

• Mohammad A. Alnajjar,
• Jürgen Bartelmeß,
• Robert Hein,
• Pichandi Ashokkumar,
• Mohamed Nilam,
• Werner M. Nau,
• Knut Rurack and
• Andreas Hennig

Beilstein J. Org. Chem. 2018, 14, 1961–1971, doi:10.3762/bjoc.14.171

• specific host–guest binding of 5 to CB7 on the surface, which suggests the use of 5 for straightforward surface functionalization to create nanophotonic devices as well as for multimodal surface group quantifications, e.g., using their optical properties for fluorescence and their fluorine heteroatom for X

Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)

• Thanh-Tuân Bui,
• Fabrice Goubard,
• Malika Ibrahim-Ouali,
• Didier Gigmes and
• Frédéric Dumur

Beilstein J. Org. Chem. 2018, 14, 282–308, doi:10.3762/bjoc.14.18

• acceptor by carbazole moieties was examined, consisting in introducing methyl groups in the proper position of the triazine or the carbazole moieties [56]. By changing the methyl group positions, optical properties of T20–T23 were not significantly modified, contrarily to their ΔEST (see Figure 7). In fact

• donor and the 4,6-diphenylpyrimidine fragment. Due to the smaller overlap of the two wavefunctions, a weaker intramolecular charge transfer was attended, enabling to provide an emission in the blue or sky-blue region. Optical properties were evaluated in solution confirming this trend, with an emission

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

• bioanalytical methods. Higher photochemical stability was demonstrated by dye 5c and this had very low fluorescence in the free state. Computational tools were used in an attempt to explain the optical properties of the studied chromophores. The results are encouraging and warrant further investigations into

Structure–property relationships and third-order nonlinearities in diketopyrrolopyrrole based D–π–A–π–D molecules

• Jan Podlesný,
• Lenka Dokládalová,
• Oldřich Pytela,
• Adam Urbanec,
• Milan Klikar,
• Numan Almonasy,
• Tomáš Mikysek,
• Jaroslav Jedryka,
• Iwan V. Kityk and
• Filip Bureš

Beilstein J. Org. Chem. 2017, 13, 2374–2384, doi:10.3762/bjoc.13.235

• of the peripheral substituents (donor) and enlargement of the π-system. Fundamental properties of target molecules were studied by differential scanning calorimetry, electrochemistry, and absorption and emission spectra. Nonlinear optical properties were studied by measuring the third harmonic

• be the strongest electron donor within the studied series of compounds. This is in accordance with our previous observations [9][35]. Except for chromophores 3a,b, insertion of an additional acetylene linker rather extended the electrochemical HOMO–LUMO gap (series a vs b). Linear optical properties

• ). Nonlinear optical properties The third harmonic generation (THG) measurements of target chromophores 1–5 were carried out by using a 1064 nm Nd:YAG source beam. Due to the relatively high absorption of chromophores 1–5 around 355 nm, the observation of the THG was possible only in the reflected light

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

• for fluorinated polymer dyes Fluoropolymers are widely used from household products to aerospace materials because they show excellent stability, as well as non-adhesive, electrical and optical properties due to the specific properties of fluorine [24][111]. Material development studies of compounds

• pertrifluoroethoxy substitutions. Synthesis and optical properties of trifluoroethoxy-substituted subphthalocyanines Subphthalocyanines [122][123][124][125] are phthalocyanine analogues unlike phthalocyanines which are planar compounds composed of four isoindoline units, and are cone-shaped distorted molecules

New electroactive asymmetrical chalcones and therefrom derived 2-amino- / 2-(1H-pyrrol-1-yl)pyrimidines, containing an N-[ω-(4-methoxyphenoxy)alkyl]carbazole fragment: synthesis, optical and electrochemical properties

• Daria G. Selivanova,
• Alexei A. Gorbunov,
• Olga A. Mayorova,
• Alexander N. Vasyanin,
• Igor V. Lunegov,
• Elena V. Shklyaeva and
• Georgii G. Abashev

Beilstein J. Org. Chem. 2017, 13, 1583–1595, doi:10.3762/bjoc.13.158

• -methoxyphenoxy)alkyl]carbazole fragment. Such readily functionalizable heterocycle as carbazole was used as a main starting compound for their preparation. The investigation of the optical properties has shown that the positive solvatochromism is inherent to the chromophores containing an electron-withdrawing

• The optical properties of all synthesized compounds were studied with the help of UV–vis absorption and fluorescence spectroscopy of their solutions in various solvents. It has been found out that all the prepared compounds bearing 9-[ω-(4-methoxyphenoxy)alkyl]carbazole moieties are readily soluble in

• substituent at the C3 atom of the carbazole cycle: 2a,b – formyl group, 3a,b – acetyl group, 4a,b – 1-chloro-3-oxoprop-1-en-1-yl moiety and 5a,b – 5-acetylthiophen-2-yl unit. That’s why it is interesting to compare their optical properties. So, we have fulfilled the overlapping of the absorption and emission

Synthesis and metal binding properties of N-alkylcarboxyspiropyrans

• Alexis Perry and
• Christina J. Kousseff

Beilstein J. Org. Chem. 2017, 13, 1542–1550, doi:10.3762/bjoc.13.154

• with the facile elaboration of the spiropyran core, have made spiropyran–merocyanine systems a common motif in molecular switch and sensing applications [2]. In this respect, the difference in optical properties between colourless, non-fluorescent spiropyran and coloured, fluorescent merocyanine has

Glyco-gold nanoparticles: synthesis and applications

• Federica Compostella,
• Olimpia Pitirollo,
• Alessandro Silvestri and
• Laura Polito

Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100

• presentation of saccharide moieties and to exploit the peculiar optical properties of the metallic core. In this review, we present recent advances on glyco-gold nanoparticle applications in different biological fields, highlighting the key parameters which inspire the glyco nanoparticle design. Keywords

• performing system. Gold core: optical properties AuNPs, widely employed for biomedical applications, are characterized by inert nature, resisting to air oxidation and corrosion [30]. This chemical non-reactivity and inertness make AuNPs an outstanding candidate for the development of in vitro and in vivo

• devices [31][32]. Furthermore, in vitro and in vivo short term reduced toxicity of AuNPs has been widely documented [10][33][34][35][36][37][38]. AuNPs own a number of peculiar optical properties, strongly dependent on the size and the morphology of the metallic core. When AuNP dimension is comparable to