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

• irradiation times was determined by HPLC analysis, for the solid samples by measuring the luminescence intensities of the samples. The majority of the experiments was performed at least twice and was reproducible within an estimated error of <10%. The degradation curves were generated by using the average

• beginning of the experiment (Figure 3). However, after 15–20 min of irradiation, the luminance changes decrease significantly. A possible explanation is the formation of degradation products which are still capable of phosphorescent emission, albeit at lower luminescence quantum efficiencies. This rational

Synthesis, photophysical and electrochemical characterization of terpyridine-functionalized dendritic oligothiophenes and their Ru(II) complexes

• Amaresh Mishra,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2013, 9, 866–876, doi:10.3762/bjoc.9.100

• ligands, 2,2':6',2"-terpyridine (tpy) has been used extensively, despite the low luminescence displayed by these complexes, due to the interesting geometry of the tpy ligand, which allows axial type arrangement of the substituents placed on the 4'-position of the coordinated tpy. Among them, ligands of

• increasing generation. Therefore, UV–vis absorption and luminescence spectra of ligands 8, 9 and metallodendrimers 1, 2 were measured and analyzed (Table 1). Absorption spectra of ligands 8, 9 and complexes 1, 2 in air-equilibrated acetonitrile at 293 K are shown in Figure 1a and summarized in Table 1

• + complex (Δλem = 64 and 126 nm, respectively, Table 1) [48], indicating that the 3MLCT luminescence energy levels in these complexes undergo a stabilization with increasing size of the thienylene-ethynylene units [18]. Beley et al. reported a similar red-shift of the 3MLCT emission band for the [Ru(tpy-th

Superstructures of fluorescent cyclodextrin via click-reaction

• Arkadius Maciollek,
• Helmut Ritter and
• Rainer Beckert

Beilstein J. Org. Chem. 2013, 9, 827–831, doi:10.3762/bjoc.9.94

• Elmer LS55 luminescence spectrometer. AF4 measurements in ultrapure water were carried out on a combined system comprising the following elements: refractive index detector Optilabrex (Wyatt Technologies, laser wavelength 658 nm), three angle light scattering detector miniDawn TREOS (Wyatt Technologies

Spin state switching in iron coordination compounds

• Philipp Gütlich,
• Ana B. Gaspar and
• Yann Garcia

Beilstein J. Org. Chem. 2013, 9, 342–391, doi:10.3762/bjoc.9.39

Synthesis and characterization of low-molecular-weight π-conjugated polymers covered by persilylated β-cyclodextrin

• Aurica Farcas,
• Ana-Maria Resmerita,
• Andreea Stefanache,
• Mihaela Balan and
• Valeria Harabagiu

Beilstein J. Org. Chem. 2012, 8, 1505–1514, doi:10.3762/bjoc.8.170

• particular have been the focus of much research as encouraging candidates for organic light-emitting diodes (OLEDs) due to their pure blue luminescence and high efficiency [5][6][7][8][9][10]. The application of PFs and PDOF conjugated polymers is limited by unwanted side effects, such as aggregation and a

• the sample in a temperature range 25–800 °C. Absorption spectra were measured on a Specord 200 spectrophotometer in CHCl3 solution and on thin films. Fluorescence spectra were obtained with a Perkin Elmer LS55 luminescence spectrophotometer. The surface images were obtained with a Solver PRO-M

A simple and efficient dual optical signaling chemodosimeter for toxic Hg(II)

• Sabir H. Mashraqui,
• Sapna A. Tripathi,
• Sushil S. Ghorpade and
• Smita R. Britto

Beilstein J. Org. Chem. 2012, 8, 1352–1357, doi:10.3762/bjoc.8.155

• ratiometric or switch-on responses even for the paramagnetic metal ions [17][18][19]. The first luminescence chemodosimeter for Hg2+ was developed by Czarnik et al. and was based on the Hg2+-mediated desulfurization of anthracene-thioamide chromophore [20][21]. Following this pioneering report, several other

Synthesis of new pyrrole–pyridine-based ligands using an in situ Suzuki coupling method

• Matthias Böttger,
• Björn Wiegmann,
• Steffen Schaumburg,
• Peter G. Jones,
• Wolfgang Kowalsky and
• Hans-Hermann Johannes

Beilstein J. Org. Chem. 2012, 8, 1037–1047, doi:10.3762/bjoc.8.116

• nine and thereby saturated. Our interest in this type of complex is driven by its potential analytical application for luminescence degradation measurements on photocatalytic surfaces [8]. Currently, β-diketonate complexes are in use for this analysis, but homoleptic complexes may be advantageous in

Sexithiophenes as efficient luminescence quenchers of quantum dots

• Christopher R. Mason,
• Yang Li,
• Paul O’Brien,
• Neil J. Findlay and
• Peter J. Skabara

Beilstein J. Org. Chem. 2011, 7, 1722–1731, doi:10.3762/bjoc.7.202

• Sexithiophenes 1a and 1b, in which a 4-(dimethylamino)phenyl unit is incorporated as an end-capping group, were synthesised and characterised by cyclic voltammetry, absorption spectroscopy and UV–vis spectroelectrochemistry. Additionally, their ability to function as effective luminescence quenchers for quantum

• dot emission was studied by photoluminescence spectroscopy and compared with the performance of alkyl end-capped sexithiophenes 2a and 2b. Keywords: electrochemistry; luminescence quenching; quantum dots; sexithiophenes; synthesis; Introduction Structurally well-defined oligothiophenes as functional

• , while the high-energy absorption edge for the nanocrystals is 657 nm. Comparison with the absorption profiles for 1b and 2b confirms that no overlap occurs between the emission from the quantum dot and the absorption by the oligothiophene (Figure 5). As such, any luminescence quenching observed would

Synthesis of (−)-julocrotine and a diversity oriented Ugi-approach to analogues and probes

• Ricardo A. W. Neves Filho,
• Bernhard Westermann and
• Ludger A. Wessjohann

Beilstein J. Org. Chem. 2011, 7, 1504–1507, doi:10.3762/bjoc.7.175

• reagent, to yield the designed probe prototype 10 in 80% yield (from 8). Pyrene derivative 10 exhibited strong blue luminescence in both solution and solid phase. This probe may be used for tracking the (−)-julocrotine in biological systems, in particular in promastigote and amastigote forms of protozoan

Novel carbazole–pyridine copolymers by an economical method: synthesis, spectroscopic and thermochemical studies

• Aamer Saeed,
• Madiha Irfan and
• Shahid Ameen Samra

Beilstein J. Org. Chem. 2011, 7, 638–647, doi:10.3762/bjoc.7.75

• luminescence, high thermal stability and excellent photoconductivity. Furthermore, the functionalization of the carbazole nucleus can easily be carried out at the 3-, 6- and 9-positions to afford a great diversity of structures [16]. Carbazole containing polymers have been greatly explored during the last few

Supramolecular FRET photocyclodimerization of anthracenecarboxylate with naphthalene-capped γ-cyclodextrin

• Qian Wang,
• Cheng Yang,
• Gaku Fukuhara,
• Tadashi Mori,
• Yu Liu and
• Yoshihisa Inoue

Beilstein J. Org. Chem. 2011, 7, 290–297, doi:10.3762/bjoc.7.38

• recorded on a Bruker DRX-600 or a JEOL JNM-EX 400 spectrometer. UV–vis, fluorescence, and circular dichroism spectra were recorded in a UNISOKU USP-203CD cryostat with a JASCO V-560 spectrophotometer, JASCO FP-6500 luminescence spectrometer, and JASCO J-810 spectropolarimeter, respectively

An easy assembled fluorescent sensor for dicarboxylates and acidic amino acids

• Xiao-bo Zhou,
• Yuk-Wang Yip,
• Wing-Hong Chan and
• Albert W. M. Lee

Beilstein J. Org. Chem. 2011, 7, 75–81, doi:10.3762/bjoc.7.11

• and 13C NMR spectra were recorded on a Bruker Avance-III spectrometer (at 400 and 100 MHz, respectively) in DMSO-d6 or CDCl3. High resolution mass spectra were recorded on a Bruker Autoflex mass spectrometer (MALDI TOF). Fluorescent emission spectra were taken on a Perkin Elmer LS 50B luminescence

Donor-acceptor substituted phenylethynyltriphenylenes – excited state intramolecular charge transfer, solvatochromic absorption and fluorescence emission

• Ritesh Nandy and
• Sethuraman Sankararaman

Beilstein J. Org. Chem. 2010, 6, 992–1001, doi:10.3762/bjoc.6.112

• acceptor depending upon the substituent. Pyrene- π spacer-donor and pyrene- π spacer-acceptor type molecules have been widely studied and they have been used in sensing, photo and electro-luminescence applications [31][32][33][34][35][36]. Unlike pyrene, the triphenylene chromophore has not been widely

Pyridinium based amphiphilic hydrogelators as potential antibacterial agents

• Sayanti Brahmachari,
• Sisir Debnath,
• Sounak Dutta and
• Prasanta Kumar Das

Beilstein J. Org. Chem. 2010, 6, 859–868, doi:10.3762/bjoc.6.101

• was also in accord with the FESEM images. The participation of the pyridinium ring in hydrogelation was investigated by taking the luminescence spectra of the efficient gelator 2 at various concentrations (0.01–3.0%, w/v) in water (Figure 4) at room temperature. The amphiphile 2 was excited at λ = 330

• ionization (ESI) technique on a Q-Tof-micro Quadruple mass spectrometer (Micromass). Fluorescence and FTIR spectra were measured on a Varian Cary Eclipse luminescence spectrometer and a Perkin Elmer Spectrum 100 FTIR spectrometer, respectively. General synthetic procedure Synthesis of amphiphiles 1–5 The

• spectra of the compound 2 were recorded on Varian Cary Eclipse luminescence spectrometer in the concentration range from 0.01%, w/v to above MGC (3%, w/v). A super stock solution of 2 was prepared and diluted as required. The compound was excited at λex = 330 nm and emission recorded between 340–550 nm

Conjugated polymers containing diketopyrrolopyrrole units in the main chain

• Bernd Tieke,
• A. Raman Rabindranath,
• Kai Zhang and
• Yu Zhu

Beilstein J. Org. Chem. 2010, 6, 830–845, doi:10.3762/bjoc.6.92

• fastness, deep colour, luminescence with large Stokes-shifts, and a brilliant red colour enabling technical applications in colouring of fibers, plastics and surface coatings such as prints or inks. The electron-withdrawing effect of the lactam units causes the chromophore to have a high electron affinity

• monomer as well as conventional Pd-catalyzed coupling of M-1 and the 3,6-diphenyl(4,4´-bis(pinacolato)boron ester) derivative of DPP. The polymer exhibits a bordeaux-red colour in solution with absorption maxima of about 525 nm, and a purple luminescence with a maximum around 630 nm with a Stokes-shift of

• colours, intense luminescence, high luminescence quantum yields, and Stokes-shifts up to 110 nm. Some of the polymers were studied as active layers in electroluminescent devices and showed a brightness up to 500 cd m−2. Polymers with dithiophenylDPP moieties in the main chain show broad absorption in the

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

Ring opening metathesis polymerization-derived block copolymers bearing chelating ligands: synthesis, metal immobilization and use in hydroformylation under micellar conditions

• Gajanan M. Pawar,
• Jochen Weckesser,
• Siegfried Blechert and
• Michael R. Buchmeiser

Beilstein J. Org. Chem. 2010, 6, No. 28, doi:10.3762/bjoc.6.28

• was performed using a Perkin-Elmer luminescence spectrometer LS50B. IR spectra were recorded on a Bruker Vector 22 using ATR technology. Elemental analysis was carried out on Elementar Varia El (Analytik Jena). GC-MS investigations were carried out on a Shimadzu GCMS-QP5050 with an AOC-20i Autosampler

Functional properties of metallomesogens modulated by molecular and supramolecular exotic arrangements

• Alessandra Crispini,
• Mauro Ghedini and
• Daniela Pucci

Beilstein J. Org. Chem. 2009, 5, No. 54, doi:10.3762/bjoc.5.54

• materials with more and more challenging requirements such as improved charge transport, luminescence, chirality and biological functions for high-tech applications has been directed towards the use of new mesomorphic systems [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Design principles based only on

• -one) as a cyclometallating ligand and from the suitably functionalized curcumin β-diketonate as a complementary O,O chelating ligand (Figure 1). The presence of the principal ligand [39][40][41][42][43][44] introduces interesting luminescence properties into the metallic system (which is luminescent

• organized into columns, the broad thermal stability and the luminescence in the red region of the visible spectrum make this new Pd(II) complex a very intriguing candidate for applications in OLED devices. A further class of ortho-palladated complexes has been obtained starting from the 2-phenylquinoline, a