Photoinduced homolytic C–H activation in N-(4-homoadamantyl)phthalimide

• Nikola Cindro,
• Margareta Horvat,
• Kata Mlinarić-Majerski,
• Axel G. Griesbeck and
• Nikola Basarić

Beilstein J. Org. Chem. 2011, 7, 270–277, doi:10.3762/bjoc.7.36

• protic solvent, undergoes H-abstraction to give products with ten times higher quantum yields than in an aprotic solvent. Such a finding is in accordance with previous reports for phthalimides and is probably due to a switching of the relative order of the singlet and the triplet excited states of the

A new fluorescent chemosensor for fluoride anion based on a pyrrole–isoxazole derivative

• Zhipei Yang,
• Kai Zhang,
• Fangbin Gong,
• Shayu Li,
• Jun Chen,
• Jin Shi Ma,
• Lyubov N. Sobenina,
• Albina I. Mikhaleva,
• Guoqiang Yang and
• Boris A. Trofimov

Beilstein J. Org. Chem. 2011, 7, 46–52, doi:10.3762/bjoc.7.8

• recorded on a Hitachi F-4500 fluorescence spectrophotometer. Fluorescence quantum yields (ФF) were determined by the comparative method using 1,4-bis(5-phenyl-2-oxazolyl)benzene (ФF = 0.97) as reference standard [12]. 1H NMR spectra were recorded on a Bruker dmx 400 MHz NMR spectrometer at room temperature

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

• 1e, the quantum yield of fluorescence was measured in ethanol. The fluorescence quantum yields for these derivatives in ethanol were low, presumably due to facile electron transfer and hydrogen bonding interaction with the solvent which enhances the non-radiative processes. In polar solvents electron

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

• soluble polymers P-2 to P-8 exhibiting yellow to red absorption and emission colours, and fluorescence quantum yields of up to 86% were obtained. Characteristic properties are compiled in Table 1. Compared with the DPP monomers, the absorption of most of the polymers was bathochromically shifted by 24 to

• P-11 exhibited a maximum absorption at 560 nm, and a solution-cast film of the same polymer had a λmax-value of 581 nm. The band gaps were between 1.5 and 1.7 eV, i.e., considerably smaller than for the previously reported DPP-based polymers. The fluorescence quantum yields Φ of the copolymers were

• copolymerized with primary or secondary arylamines to yield DPP-containing polyiminoarylenes. The solutions of the polymers in chloroform exhibited a purple red colour with absorption maxima between 530 and 550 nm, and emission maxima from 610 to 630 nm. Fluorescence quantum yields were moderate (20 to 60

Synthetic incorporation of Nile Blue into DNA using 2′-deoxyriboside substitutes: Representative comparison of (R)- and (S)-aminopropanediol as an acyclic linker

• Daniel Lachmann,
• Sina Berndl,
• Otto S. Wolfbeis and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2010, 6, No. 13, doi:10.3762/bjoc.6.13

• protocol, worked up and purified according to literature [17]. The two Nile Blue-modified oligonucleotides DNA1 and DNA2 were identified by ESI mass spectrometry, quantified by UV–vis absorption and characterized by fluorescence spectroscopy (including quantum yields) and measurement of melting

• contrast to the absorption properties that were pretty similar for all Nile Blue-modified duplexes, fluorescence spectra show the influence of the sequential neighborhood. The quantum yields of the Nile Blue-modified single strands are reduced from 33% for the isolated dye in ethanol to 15% in the single

• the chromophore has been attached via the R-configured linker (this study) or the S-configured one [17]. The comparison of quantum yields (Table 1) reflects only very minor differences that are within the experimental error. It was quite surprising to observe that in contrast to experiments with D

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

• in solution), in the red region of the Vis spectrum (λ = 610 nm), with emission quantum yields in the range of 6–23%, depending on the solvent. However, the 3,4,5-trialkoxy-substituted benzoato fragment of the curcumin ligand imposes an overall hemi-disc structure to the resulting palladium

Reversible intramolecular photocycloaddition of a bis(9-anthrylbutadienyl)paracyclophane – an inverse photochromic system. (Photoactive cyclophanes 5)

• Henning Hopf,
• Christian Beck,
• Jean-Pierre Desvergne,
• Henri Bouas-Laurent,
• Peter G. Jones and
• Ludger Ernst

Beilstein J. Org. Chem. 2009, 5, No. 20, doi:10.3762/bjoc.5.20

• concentration, no intermolecular reaction could compete with an intramolecular process [12]. Disappearance quantum yields at 394 nm were found to be low in methylcyclohexane (1.5 × 10−4) and in acetonitrile (4.2 × 10−2). The weakness of the cyclophotoaddition probably reflects a preference for internal

• balance (sensitivity 10−7 g). Quantum yields Reaction quantum yields were determined as described elsewhere [29], using the Parker iron trioxalate actinometer. The monochromatic beams were obtained from a cooled 1000 W Xenon lamp, using a Bausch and Lomb monochromator. The samples were previously purged

Synthesis of coumarin or ferrocene labeled nucleosides via Staudinger ligation

• Ivana Kosiova,
• Andrea Janicova and
• Pavol Kois

Beilstein J. Org. Chem. 2006, 2, No. 23, doi:10.1186/1860-5397-2-23

• ), which were synthesised in our department as part of studies into new ligands. Coumarins as fluorescent probes or labels [28][29][30] have extensive and diverse applications, they exhibit extended spectral range, are photostable and have high emission quantum yields. Ferrocene derivatives are often used