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

• wide emission band during operation [8]. Taking into account the relevant photophysical properties of these organic compounds, new synthetic approaches were developed. Copolymerization of fluorene with thiophene, bithiophene or other aromatic comonomers is an alternative method for tuning the optical

• photophysical properties of PFs by using persilylated γ-CD as a new host molecule [33]. Inclusion of bithiophene into persilylated β-cyclodextrin, randomly methylated β-cyclodextrin, or chemically modified CD derivatives, followed by copolymerization with fluorene monomers results in significant changes in the

• illustrated in Scheme 1. In order to analyse the influence of end-capping reagents on the photophysical properties we changed the termination of the growing chains to 3T instead of bromobenzene, as in previously reported results [12]. A noncomplexed PDOF-BT copolymer was also synthesized by polycondensation

Diarylethene-modified nucleotides for switching optical properties in DNA

• Sebastian Barrois and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2012, 8, 905–914, doi:10.3762/bjoc.8.103

• with a variety of photophysical properties (mainly fluorescence) in DNA. It is important to mention here that guanine does not influence the photochromic properties of the diarylethene switch 4 as a DNA modification. In fact, the photoswitching behavior of 4 is maintained in all four different DNA

Molecular switches and cages

• Dirk Trauner

Beilstein J. Org. Chem. 2012, 8, 870–871, doi:10.3762/bjoc.8.97

• photoswitches continue to emerge and “old friends”, such as azobenzenes are constantly improved and optimized. This is not only true with respect to their photophysical properties but also with regard to their synthetic accessibility. Indeed, as molecular switches are applied in ever-increasing quantities, the

Syntheses and applications of furanyl-functionalised 2,2’:6’,2’’-terpyridines

• Jérôme Husson and
• Michael Knorr

Beilstein J. Org. Chem. 2012, 8, 379–389, doi:10.3762/bjoc.8.41

• photophysical properties, making them interesting in materials science [9][10][11][12]. Finally, the rich chemistry associated with five-membered heterocycles easily allows various chemical modifications. In this respect, the attachment of such heterocycles, directly or through a linker, to a tpy system appears

• electrochemical and photophysical properties of such compounds is therefore of crucial importance. In this context, the octahedral Ru(II) complex 43 was studied and compared with analogous pyrrolyl, thienyl and bithienyl-substituted compounds 66–68 (Figure 4) in order to obtain information about the influence of

• the pendant heterocycle on the physicochemical properties [56]. It appeared from this study that the bithienyl substituent has the most pronounced effect on the photophysical properties of this series of Ru complexes. Especially, 68 absorbs at a longer wavelength (Table 4), which constitutes an

Self-assembly of Ru₄ and Ru₈ assemblies by coordination using organometallic Ru(II)₂ precursors: Synthesis, characterization and properties

• Sankarasekaran Shanmugaraju,
• Dipak Samanta and
• Partha Sarathi Mukherjee

Beilstein J. Org. Chem. 2012, 8, 313–322, doi:10.3762/bjoc.8.34

• having complementary binding sites. Large numbers of molecular polygons and polyhedra have been synthesized mostly from cis-blocked Pd(II)- and Pt(II)-based building units due to their rigid square-planar coordination geometry as well as to their interesting photophysical properties [3][4][5]. However

Fluorescent hexaaryl- and hexa-heteroaryl[3]radialenes: Synthesis, structures, and properties

• Antonio Avellaneda,
• Courtney A. Hollis,
• Xin He and
• Christopher J. Sumby

Beilstein J. Org. Chem. 2012, 8, 71–80, doi:10.3762/bjoc.8.7

• deficient hexaaryl[3]radialene observed thus far, and studies of their electrochemical and photophysical properties. Results and Discussion The first new [3]radialene compound targeted was hexa(pyrazol-1-yl)[3]radialene. However, the required starting material, 1-[(1H-pyrazol-1-yl)methyl]-1H-pyrazole

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

• be very efficient pH-triggered NLO switches. The fluorescent and photophysical properties of chromophores 88–93 were further studied [110][111]. The fluorescence was studied in various solvents and polymer matrices and at various temperatures. Intense fluorescence with quantum yields of 0.05 to 0.98

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

• , with retention of the photoluminescence behaviour of the quantum dot [24]. Herein, we present a comparative study on the photophysical properties of sexithiophenes 1 or 2 in varying concentrations, in the presence of a fixed concentration of CdSe(ZnS) core/shell quantum dots. Our choice of compounds

• charged species. This increase is a consequence of the resonance effect of the phenyldimethylamine group. Sexithiophene/quantum dot composites in solution A comparative study on the photophysical properties of sexithiophenes 1a,b and 2a,b, in varying concentrations, with a fixed concentration of CdSe(ZnS

Synthesis and characterization of new diiodocoumarin derivatives with promising antimicrobial activities

• Hany M. Mohamed,
• Ashraf H. F. Abd EL-Wahab,
• Ahmed M. EL-Agrody,
• Ahmed H. Bedair,
• Fathy A. Eid,
• Mostafa M. Khafagy and
• Kamal A. Abd-EL-Rehem

Beilstein J. Org. Chem. 2011, 7, 1688–1696, doi:10.3762/bjoc.7.199

• ]. Moreover, coumarin-based dyes and pigments are organic fluorescent materials exhibiting unique photochemical and photophysical properties, which render them useful in a variety of applications such as dye lasers, anion sensors, organic light-emitting diodes and solar cells [9][10]. Iodo-organic derivatives

Synthesis of dye/fluorescent functionalized dendrons based on cyclotriphosphazene

• Aurélien Hameau,
• Sabine Fuchs,
• Régis Laurent,
• Jean-Pierre Majoral and
• Anne-Marie Caminade

Beilstein J. Org. Chem. 2011, 7, 1577–1583, doi:10.3762/bjoc.7.186

• publications have reported the synthesis, the study of photophysical properties and several uses of fluorescent dendrimers, emphasizing in particular their role as light-harvesters [4] for organic light-emitting diodes (OLEDs) [5] and as tools in biology [6]. Many different types of fluorophores have been

Fine-tuning alkyne cycloadditions: Insights into photochemistry responsible for the double-strand DNA cleavage via structural perturbations in diaryl alkyne conjugates

• Wang-Yong Yang,
• Samantha A. Marrone,
• Nalisha Minors,
• Diego A. R. Zorio and
• Igor V. Alabugin

Beilstein J. Org. Chem. 2011, 7, 813–823, doi:10.3762/bjoc.7.93

• states in these three isomers, whilst Stern–Volmer quenching experiments were used to investigate the kinetics of PET in these three systems. In the final part of this paper, we examine whether the observed trends in photochemical and photophysical properties correlate with DNA-cleaving activities of the

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

• polymer is 154 °C. All the polymers show glass transition temperatures above 150 °C (Table 1). Photophysical properties of the polymers The photophysical properties of the polymer, including absorption and emission spectral studies, were determined from solutions in chloroform. A summary of the measured

• * transition, and the shoulders correspond to n→π* transitions in the respective materials. A comparison of the photophysical properties of the synthesized polymers may be made with structurally related polymers previously synthesized by Zheng et al. [21][28]. The observed differences in the absorption spectra

Polar tagging in the synthesis of monodisperse oligo(p-phenyleneethynylene)s and an update on the synthesis of oligoPPEs

• Dhananjaya Sahoo,
• Susanne Thiele,
• Miriam Schulte,
• Navid Ramezanian and
• Adelheid Godt

Beilstein J. Org. Chem. 2010, 6, No. 57, doi:10.3762/bjoc.6.57

• Oligo(p-phenyleneethynylene)s (oligoPPEs) have been frequently used as structural units for nanoscopic molecules because of their geometry and their electronic and photophysical properties [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. For their preparation three widely used

Preparation of pyridine-3,4-diols, their crystal packing and their use as precursors for palladium-catalyzed cross-coupling reactions

• Tilman Lechel,
• Irene Brüdgam and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2010, 6, No. 42, doi:10.3762/bjoc.6.42

• analysed with regard to their photophysical properties. Results and Discussion The preparation of pyridine-3,4-diol derivatives as depicted in Scheme 1 succeeded by using highly substituted trifluoromethyl-substituted 4-hydroxypyridine precursors 1 that have been prepared in two steps from lithiated

• that with the corresponding bistriflate. A subsequent cleavage of the triisopropylsilyl group with a fluoride source provided product 5 in 58% yield. The biscoupling reaction led to extended π-systems which might have interesting photophysical properties [31][32][33]. Hence, absorption and emission of

• extended π-systems using palladium-catalyzed coupling reactions. Moreover, compounds 4b–c show interesting photophysical properties that might be thoroughly investigated in the future. The 3,4-dialkynyl-pyridine derivatives 4 or 5 are also candidates for Bergman cyclizations [34][35] which may establish a

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

• ligands and organic ammonium ions monitored by changes in their photophysical properties in acetonitrile [152]. With the enantiomerically pure (R,R)-ligand good binding and enantiodiscrimination in favor of the S-enantiomers of PEA (20b) [150] (Kass = 2.3 × 106 M−1) and NEA (Kass = 1.7 × 106 M−1) over the

Synthesis of novel photochromic pyrans via palladium- mediated reactions

• Christoph Böttcher,
• Gehad Zeyat,
• Saleh A. Ahmed,
• Elisabeth Irran,
• Thorben Cordes,
• Cord Elsner,
• Wolfgang Zinth and
• Karola Rueck-Braun

Beilstein J. Org. Chem. 2009, 5, No. 25, doi:10.3762/bjoc.5.25

• starting material and product under the harsh reaction conditions. All attempts to use MeOH in THF under similar conditions failed to produce detectable amounts of the desired methyl ester. Photochemistry of benzopyrans: Compound 5a Photophysical properties of the novel pyrans are exemplified with compound

Synthesis and redox behavior of new ferrocene- π-extended- dithiafulvalenes: An approach for anticipated organic conductors

• Abdelwareth A. O. Sarhan,
• Omar F. Mohammed and
• Taeko Izumi

Beilstein J. Org. Chem. 2009, 5, No. 6, doi:10.3762/bjoc.5.6

• conjugated spacer. Femtosecond time-resolved absorption and Raman studies are in progress to aid in the understanding of the photophysical properties of the bis(1,3-DTF)Fc-TCNQ charge transfer complexes, trying to pick up the transient of the mono- and dication and anion radical of these systems with TCNQ

• , respectively. From this study we can estimate the timescales of the charge separation and recombination of the produced radical ion pairs. Such laser spectroscopic studies will have a big impact in future, leading not only new synthetic applications, but also to the discovery of new photophysical properties of