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

• the light-emitting ability of the emitter, which is directly related to the nature, and the photoluminescence quantum yield (PLQY) of the emitter. Based on spin statistics, upon electrical excitation, singlet and triplet excitons are formed in a 1:3 ratio [4]. In the case of fluorescent materials

• on T13 and T14 showed the two molecules to exhibit a similar electronic distribution, what was confirmed by UV–visible and photoluminescence (PL) spectroscopy. Only a slight red shift of the absorption was detected for T14 as the result of the strengthened donating ability of the dicarbazolylphenyl

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

• attached to a FAST ComTec multichannel scalar card with a time resolution of 250 ps. Photoluminescence quantum yields PL were determined with a Hamamatsu C9920-02 system equipped with a Spectralon® integrating sphere. Computational details Molecular geometries and electronic structures were calculated

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

• tetracyclic moieties are planar. The benzophosphole-fused indoles, such as phosphine oxide, phospholium salt, and borane complex, exhibited strong photoluminescence in dichloromethane (Φ = 67–75%). Keywords: benzophospholo[3,2-b]indole; DFT calculation; molecular structure; phosphole derivatives

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

• the gold Fermi wavelength, the nanoparticles acquire photoluminescence properties [31]. These small clusters typically present a diameter between 0.5 and 2 nm. When clusters are bigger, they do not present fluorescent emission but they show a localized surface plasmon resonance (LSPR) around 520 nm

• colloidal solution color. Therefore, several biosensors for the detection of proteins [42], lectin [25][27][43], cancer biomarkers [28] and viruses [44][45] were developed. Photoluminescence properties of ultrasmall gold nanoclusters and nanodots have been exploited to detect Escherichia coli (a bacteria

Molecular-level architectural design using benzothiadiazole-based polymers for photovoltaic applications

• Vinila N. Viswanathan,
• Arun D. Rao,
• Upendra K. Pandey,
• Arul Varman Kesavan and
• Praveen C. Ramamurthy

Beilstein J. Org. Chem. 2017, 13, 863–873, doi:10.3762/bjoc.13.87

• 1.87 eV, respectively. Again, a lower band gap is observed for P3 owing to the extended conjugation over the other polymers. The combined optical, electrochemical, and theoretical calculations are summarized in Table 2. Photoluminescence (PL) quenching studies were performed with pure donor polymers

• their HOMO–LUMO orbitals obtained from DFT calculations. Theoretical absorption spectra of the polymers P1–P3 calculated using TDDFT. Electrochemical spectra of polymers P1–P3. Normalized absorption spectra of the polymers in solution, film and annealed film (130 °C) forms. Photoluminescence spectra of

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

• , chemical sensing, biosensing, bioimaging and nanomedicine, due to their unique tuneable photoluminescence (PL) properties, chemical inertness, high water solubility, ease and low cost fabrication and more importantly, low toxicity profiles. The latter makes these fluorescent nanomaterials attractive for a

• show that the use of PEG-200, as a surface passivation agent (SPA), was crucial for favourable photoluminescence (PL) properties and QYs of up to 6.3% were achieved. The use of SPAs is among one of two main techniques that are widely employed to improve the PL properties of FCDs. SPAs are argued to

Synthesis and optical properties of new 5'-aryl-substituted 2,5-bis(3-decyl-2,2'-bithiophen-5-yl)-1,3,4-oxadiazoles

• Anastasia S. Kostyuchenko,
• Tatyana Yu. Zheleznova,
• Anton J. Stasyuk,
• Aleksandra Kurowska,
• Wojciech Domagala,
• Adam Pron and
• Alexander S. Fisyuk

Beilstein J. Org. Chem. 2017, 13, 313–322, doi:10.3762/bjoc.13.34

• the case of 15f,g (Figure 2). The measured photoluminescence quantum yields decrease in the following order: 15b (0.84) > 15d (0.49) > 15g (0.29) > 15e (0.25) > 15c (0.20) ≈ 15f (0.18), indicating that for larger substituents the non-radiative rate constant increases. Such phenomena are frequently

• -bis(3-decyl-2,2'-bithiophen-5-yl)-1,3,4-oxadiazoles 15b–g: a) absorption spectra, b) photoluminescence spectra in DCM. General structure of 5'-aryl-substituted 2,5-bis(3-decyl-2,2'-bithiophen-5-yl)-1,3,4-oxadiazoles. Frontier molecular orbitals (HOMO−1, HOMO, LUMO and LUMO+1) and values for HOMO–LUMO

Comparing blends and blocks: Synthesis of partially fluorinated diblock polythiophene copolymers to investigate the thermal stability of optical and morphological properties

• Pierre Boufflet,
• Sebastian Wood,
• Jessica Wade,
• Zhuping Fei,
• Ji-Seon Kim and
• Martin Heeney

Beilstein J. Org. Chem. 2016, 12, 2150–2163, doi:10.3762/bjoc.12.205

• 130 mW focussed to a 40 μm2 area. The photoluminescence background was subtracted from the spectra using a polynomial baseline and then the spectra were normalized to the main peak. A Linkam THMS600 hot-cold cell purged with nitrogen was used to prevent polymer degradation as well as to control the

Indenopyrans – synthesis and photoluminescence properties

• Andreea Petronela Diac,
• Ana-Maria Ţepeş,
• Albert Soran,
• Ion Grosu,
• Anamaria Terec,
• Jean Roncali and
• Elena Bogdan

Beilstein J. Org. Chem. 2016, 12, 825–834, doi:10.3762/bjoc.12.81

• significantly higher in the case of the trans isomers 2' as compared to the corresponding cis isomers 2'' (Table 3). The solid-state photoluminescence properties of the dihydroindenopyrones 2'a–c and 2''a–d were also investigated. These derivatives exhibit emission maxima in the range 423–491 nm when excited at

• , Supporting Information File 1) exhibit characteristic signals for the aliphatic protons: one singlet at 4.19 ppm for derivative 5c and one signal at 3.97 ppm for compound 4c, respectively. Next, the photoluminescence properties of the isolated indenopyrones 4c, 5c and 6a were investigated. The UV–vis spectra

• , UV–vis and fluorescence spectroscopy as well as mass spectrometry. Column chromatography of the crude product furnished the diastereoisomers as pure samples. The electronic spectra display two intense absorption bands ranging between 275–282 nm and 307–317 nm, while their photoluminescence spectra

Syntheses of dibenzo[d,d']benzo[2,1-b:3,4-b']difuran derivatives and their application to organic field-effect transistors

• Minh Anh Truong and
• Koji Nakano

Beilstein J. Org. Chem. 2016, 12, 805–812, doi:10.3762/bjoc.12.79

• as dibenzo[d,d']benzo[2,1-b:3,4-b']difuran (syn-DBBDF) and dinaphtho[2,3-d:2',3'-d']benzo[2,1-b:3,4-b']difuran (syn-DNBDF) were synthesized. Their photophysical and electrochemical properties were revealed by UV–vis absorption and photoluminescence spectroscopy and cyclic voltammetry. Organic field

• the π-conjugated skeleton than syn-DBBDF 5, it should possess an extended π-conjugation length, resulting in a red-shifted absorption spectrum. The HOMO–LUMO energy gaps estimated from the absorption edges were 3.72 eV and 3.32 eV for syn-DBBDF 5 and syn-DNBDF 6, respectively. Their photoluminescence

• line) in CHCl3 (1.0 × 10−5 M) and (b) normalized photoluminescence spectra of syn-DBBDF 5 (blue line) and syn-DNBDF 6 (red line) in CHCl3 (1.0 × 10−7 M). Cyclic voltammograms of syn-DBBDF 5 and syn-DNBDF 6 (measurement conditions: 1.0 mM in CH2Cl2 for syn-DBBDF 5 or Cl2CHCHCl2 for syn-DNBDF 6 with 0.1

Recent advances in metathesis-derived polymers containing transition metals in the side chain

• Ileana Dragutan,
• Valerian Dragutan,
• Bogdan C. Simionescu,
• Albert Demonceau and
• Helmut Fischer

Beilstein J. Org. Chem. 2015, 11, 2747–2762, doi:10.3762/bjoc.11.296

• copolymerizing the europium complex of the terpyridine monomer 51 with the carbazole-substituted norbornene 50. In solution or in thin film these Eu-containing products exhibited important metal-centered photoluminescence recommending them for novel applications. Unveiling and rationalizing the interactions

Synthesis and photophysical characteristics of polyfluorene polyrotaxanes

• Aurica Farcas,
• Giulia Tregnago,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert and
• Franco Cacialli

Beilstein J. Org. Chem. 2015, 11, 2677–2688, doi:10.3762/bjoc.11.288

• emitting materials owing to their pure blue emission [7][8][9][10][11]. However, some major drawbacks for their use are their high ionization potential associated with low photoluminescence (PL) efficiency, their rather large band gap and facile photochemical degradation [12][13]. Different strategies have

• [24], although clear spectroscopic signature of the presence of such species can be gleaned from time-resolved photoluminescence efficiency (PL) experiments. The PL spectra of the copolymers in CHCl3 solutions at a concentration of 10−1 mg∙mL−1 are reported in Figure 3b. The emission of the non

• surprising that we observe similar effects [33]. Interestingly, we measure a photoluminescence quantum efficiency (PLQE) of 66 ± 7% for the 3·TM-γCD, 56 ± 6% for the 3·TM-βCD and 46 ± 5% for the reference 3 polymer. Given the relatively large errors in these measurements the only conclusion we can draw is

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

• –430 nm), while π–π* transitions (300–340 nm) were red-shifted. On the other hand, diluted dichloromethane solutions (10−5 M) of diazahelicenes 2 did not show photoluminescence (Φf < 0.02, for the detailed values of quantum yields, see the Supporting Information File 1). Due to the presence of the

Synthesis of an organic-soluble π-conjugated [3]rotaxane via rotation of glucopyranose units in permethylated β-cyclodextrin

• Jun Terao,
• Yohei Konoshima,
• Akitoshi Matono,
• Hiroshi Masai,
• Tetsuaki Fujihara and
• Yasushi Tsuji

Beilstein J. Org. Chem. 2014, 10, 2800–2808, doi:10.3762/bjoc.10.297

• IMWs with polyrotaxane structures via polymerization of π-conjugated [1]rotaxane monomers bearing PMCDs as macrocycles [14]. Further, we confirmed that such IMWs with poly[1]rotaxane structure are highly soluble in a variety of organic solvents and have good rigidity, photoluminescence efficiency [15

Mono- and multilayers of molecular spoked carbazole wheels on graphite

• Stefan-S. Jester,
• A. Vikas Aggarwal,
• Daniel Kalle and
• Sigurd Höger

Beilstein J. Org. Chem. 2014, 10, 2783–2788, doi:10.3762/bjoc.10.295

• might form cocrystals with other polygons, thus patterns of increased complexity and larger lattice constants become feasible. Our MSW 2 and its precursor 1 were recently investigated by means of single-molecule photoluminescence spectroscopy as model compounds for conjugated oligomers commonly used in

Synthesis and properties of novel star-shaped oligofluorene conjugated systems with BODIPY cores

• Clara Orofino-Pena,
• Diego Cortizo-Lacalle,
• Joseph Cameron,
• Muhammad T. Sajjad,
• Pavlos P. Manousiadis,
• Neil J. Findlay,
• Alexander L. Kanibolotsky,
• Dimali Amarasinghe,
• Peter J. Skabara,
• Tell Tuttle,
• Graham A. Turnbull and
• Ifor D. W. Samuel

Beilstein J. Org. Chem. 2014, 10, 2704–2714, doi:10.3762/bjoc.10.285

• oligofluorene arm length and substitution patterns of the central BODIPY core have been synthesised, leading to two families of compounds, T-B1–T-B4 and Y-B1–Y-B4, with T- and Y-shaped motifs, respectively. Thermal stability, cyclic voltammetry, absorption and photoluminescence spectroscopy of each member of

• these two families were studied in order to determine their suitability as emissive materials in photonic applications. Keywords: absorption spectroscopy; BODIPY; cyclic voltammetry; photoluminescence; star-shaped oligofluorene; Introduction The boron-dipyrromethene (BODIPY) or 4,4-difluoro-4-bora-3a

• are dark green powders and exhibit a dark red colour in concentrated solutions and green when diluted. The colour of the T-Bn (n = 1–4) oligomers is bright pink, both in the powder form and in solution, and they give bright orange photoluminescence. The deep-red fluorescence of the Y-Bn (n = 1–4

Solution processable diketopyrrolopyrrole (DPP) cored small molecules with BODIPY end groups as novel donors for organic solar cells

• Diego Cortizo-Lacalle,
• Calvyn T. Howells,
• Upendra K. Pandey,
• Joseph Cameron,
• Neil J. Findlay,
• Anto Regis Inigo,
• Tell Tuttle,
• Peter J. Skabara and
• Ifor D. W. Samuel

Beilstein J. Org. Chem. 2014, 10, 2683–2695, doi:10.3762/bjoc.10.283

• films from a 20 mg mL−1 solution, respectively. Film thicknesses were measured using a Dektak 150 M stylus profiler. Absorption and emission spectra of compounds 9 and 10 were obtained with a Varian Cary 300 UV–visible spectrophotometer and a Photoluminescence Quantum Yield (PLQY) measurement system

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

• Edinburgh FLS 980 photoluminescence spectrometer with 1 cm quartz cells. A 375 nm pulsed diode laser (EPL-375, maximum average power: 5 mW, pulse width: 73.2 ps) was used as a light source. Decay data analysis was performed by the deconvolution procedure with multiexponential decay models. The quality of

Synthesis of new, highly luminescent bis(2,2’-bithiophen-5-yl) substituted 1,3,4-oxadiazole, 1,3,4-thiadiazole and 1,2,4-triazole

• Anastasia S. Kostyuchenko,
• Vyacheslav L.Yurpalov,
• Aleksandra Kurowska,
• Wojciech Domagala,
• Adam Pron and
• Alexander S. Fisyuk

Beilstein J. Org. Chem. 2014, 10, 1596–1602, doi:10.3762/bjoc.10.165

• synthesis, efficient ring closure reaction affording a 4H-1,2,4-triazole unit is presented. All target ambipolar compounds display strong photoluminescence with measured quantum yields up to 0.59. Modification of the demonstrated synthetic routes may be exploited for the preparation of longer, specifically

• with the thiadiazole central unit. Such a decrease of the absorption band energy is typical of all sulfur containing five membered heterocycles [14][15][34]. Upon excitation with the UV light, all investigated compounds feature strong photoluminescence, emitting blue and green light (Table 2). Their

• photoluminescence quantum yields are indicated together with the formulae of the corresponding compounds. In the case of 18 (4-phenyl-4H-1,2,4-triazole ring) the photoluminescence quantum yield is almost three times higher than that measured for 15 (1,3,4-thiadiazole ring). The obtained results clearly demonstrate

First synthesis of meso-substituted pyrrolo[1,2-a]quinoxalinoporphyrins

• Dileep Kumar Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2014, 10, 808–813, doi:10.3762/bjoc.10.76

• ][12][13], organic light emitting diodes [14][15], near infrared dyes [16][17][18], hybrid solar cells [19][20][21][22], and biosensors [23][24][25] due to their intense optical absorptions and photoluminescence characteristics. On the other hand, compounds containing a pyrrolo[1,2-a]quinoxaline

Studies on the photodegradation of red, green and blue phosphorescent OLED emitters

• Susanna Schmidbauer,
• Andreas Hohenleutner and
• Burkhard König

Beilstein J. Org. Chem. 2013, 9, 2088–2096, doi:10.3762/bjoc.9.245

• emitting Ir(F,CN-ppy)3 with its higher emission energy, a participation of this mechanism is likely. However, it was shown that iridium complexes exhibit singlet oxygen quantum efficiencies close to the photoluminescence quantum efficiencies of these compounds. Djurovich et al. suggested that back-electron

Molecular assembly of amino acid interlinked, topologically symmetric, π-complementary donor–acceptor–donor triads

• M. B. Avinash,
• K. V. Sandeepa and
• T. Govindaraju

Beilstein J. Org. Chem. 2013, 9, 1565–1571, doi:10.3762/bjoc.9.178

• details, synthesis procedures, FESEM images, absorption, photoluminescence, PXRD and 2D NOESY spectra. Acknowledgements Authors thank Prof. C. N. R. Rao, FRS for constant support and encouragement; JNCASR, DST, IYBA-DBT and the government of India for financial support; Prof. G. U. Kulkarni for the FESEM

Enaminones in a multicomponent synthesis of 4-aryldihydropyridines for potential applications in photoinduced intramolecular electron-transfer systems

• Nouria A. Al-Awadi,
• Maher R. Ibrahim,
• Mohamed H. Elnagdi,
• Elizabeth John and
• Yehia A. Ibrahim

Beilstein J. Org. Chem. 2012, 8, 441–447, doi:10.3762/bjoc.8.50

• -naphthyl) and 4-(phenanthren-9-yl)dihydropyridine derivatives exhibited an interesting photoluminescence behavior, which suggests their potential application as suitable photoinduced intramolecular electron-transfer systems. Keywords: enaminones; 1,4-dihydropyridines; microwaves; multi-component reactions

• ; photoluminescence; Introduction There is a lot of interest in supramolecular assemblies based on transition-metal ions, which have proved to be useful for a variety of light-induced applications, from molecular machines to systems that mimic chlorophyll photosynthesis [1][2][3][4][5][6]. Recently, 4-aryl-2,6

• compounds gave fluorescence spectra (Figure 3 and Figure 4) with λmax = 454–492 nm (Table 2). This photoluminescence behavior of 6 and 7 resembles that of dihydropyridinedicarboxylate derivatives [7][8], which suggests their potential application as suitable photoinduced intramolecular electron-transfer

Laterally substituted symmetric and nonsymmetric salicylideneimine-based bent-core mesogens

• Sonja Findeisen-Tandel,
• Wolfgang Weissflog,
• Ute Baumeister,
• Gerhard Pelzl,
• H. N. Shreenivasa Murthy and
• Channabasaveshwar V. Yelamaggad

Beilstein J. Org. Chem. 2012, 8, 129–154, doi:10.3762/bjoc.8.15

• salicylideneaniline moieties are linked by an ester group (Scheme 1C). These compounds, which show a strong photoluminescence, exhibit typical banana phases B1 and B7 [31]. Yelamaggad et al. reported V-shaped five-ring mesogens: Two salicylideneaniline moieties are linked by ester groups to the 1,2-positions of a

Imidazole as a parent π-conjugated backbone in charge-transfer chromophores

• Jiří Kulhánek and
• Filip Bureš

Beilstein J. Org. Chem. 2012, 8, 25–49, doi:10.3762/bjoc.8.4

• (DOFIPh), based on the fluoreno[2,3-d]imidazole core, showed strong and tunable blue emission in the solid state (λmax,em = 417–526 nm in film), which makes these molecules potentially applicable as active layers for OLEDs [69]. Chromophores 62 were investigated as photoluminescence materials with λmax