Search results

Search for "azobenzene" in Full Text gives 99 result(s) in Beilstein Journal of Organic Chemistry.

Photoswitchable precision glycooligomers and their lectin binding

  • Daniela Ponader,
  • Sinaida Igde,
  • Marko Wehle,
  • Katharina Märker,
  • Mark Santer,
  • David Bléger and
  • Laura Hartmann

Beilstein J. Org. Chem. 2014, 10, 1603–1612, doi:10.3762/bjoc.10.166

Graphical Abstract
  • building blocks. The obtained glycoligands are monodisperse and present azobenzene moieties as well as sugar ligands at defined positions within the oligomeric backbone and side chains, respectively. We show that the combination of molecular precision together with the photoswitchable properties of the
  • azobenzene unit allows for the photosensitive control of glycoligand binding to protein receptors. These stimuli-sensitive glycoligands promote the understanding of multivalent binding and will be further developed as novel biosensors. Keywords: azobenzene; glycopolymer; lectin binding; multivalency
  • potential perspectives for the sensing and adhesion of bacteriological targets on various substrates. The examples reported so far make use of azobenzene [16], a well-known photochromic compound offering robustness and straightforward preparation. It is able to reversibly isomerize between an extended and
PDF
Album
Supp Info
Full Research Paper
Published 15 Jul 2014

4-Pyridylnitrene and 2-pyrazinylcarbene

  • Curt Wentrup,
  • Ales Reisinger and
  • David Kvaskoff

Beilstein J. Org. Chem. 2013, 9, 754–760, doi:10.3762/bjoc.9.85

Graphical Abstract
  • phenylnitrene (1) and 2-pyridylcarbene (3) has been described in considerable detail [1][2][3]. The three species 1–3 have all been observed directly by IR or ESR spectroscopy in low-temperature matrices. The normal reaction products of phenylnitrene are azobenzene (4) and aniline (5), but under forcing flash
  • described below. Since nitrenes are intrinsically more stable than the isomeric carbenes [3][12][13], a rearrangement of 21 to 19 is perfectly reasonable. In the case of phenylazide, mild FVT results in the formation of azobenzene (4) (Scheme 1), but violent FVT, where the pressure is allowed to rise to ca
PDF
Album
Supp Info
Full Research Paper
Published 17 Apr 2013

NHC-catalysed highly selective aerobic oxidation of nonactivated aldehydes

  • Lennart Möhlmann,
  • Stefan Ludwig and
  • Siegfried Blechert

Beilstein J. Org. Chem. 2013, 9, 602–607, doi:10.3762/bjoc.9.65

Graphical Abstract
  • azobenzene [8][9][10][11][12][13][14][15][16][17][18] were described. The use of mpg-C3N4 should lead to a new process containing two subsequent organocatalytic reactions (Scheme 1). Results and Discussion In initial experiments we used 4-nitrobenzaldehyde as a model substrate. As NHC-salt we selected A
PDF
Album
Full Research Paper
Published 22 Mar 2013

Thermotropic and lyotropic behaviour of new liquid-crystalline materials with different hydrophilic groups: synthesis and mesomorphic properties

  • Alexej Bubnov,
  • Miroslav Kašpar,
  • Věra Hamplová,
  • Ute Dawin and
  • Frank Giesselmann

Beilstein J. Org. Chem. 2013, 9, 425–436, doi:10.3762/bjoc.9.45

Graphical Abstract
  • -alkoxyphenyl β-D-glucopyranosides [5]. LC compounds in which a hydrophilic polyethyleneimine chain with hydroxy side-groups is attached to the azobenzene mesogenic core through the alkylene chain have showed a thermotropic SmA phase, lyotropic lamellar phase, and a lyotropic analogue of the tilted smectic C
PDF
Album
Full Research Paper
Published 25 Feb 2013

Synthesis and testing of the first azobenzene mannobioside as photoswitchable ligand for the bacterial lectin FimH

  • Vijayanand Chandrasekaran,
  • Katharina Kolbe,
  • Femke Beiroth and
  • Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2013, 9, 223–233, doi:10.3762/bjoc.9.26

Graphical Abstract
  • control of carbohydrate-specific bacterial adhesion, it has become our goal to synthesise azobenzene mannosides as photoswitchable inhibitors of type 1 fimbriae-mediated adhesion of E. coli. An azobenzene mannobioside 2 was prepared and its photochromic properties were investigated. The E→Z isomerisation
  • that of the standard inhibitor methyl mannoside. These findings could be rationalised on the basis of computer-aided docking studies. The properties of the new azobenzene mannobioside have qualified this glycoside to be eventually employed on solid support, in order to fabricate photoswitchable
  • adhesive surfaces. Keywords: azobenzene glycosides; bacterial adhesion; E/Z photoisomerisation; FimH antagonists; mannobiosides; molecular switches; sweet switches; Introduction Adhesion of bacteria to surfaces can be a severe problem both in vivo and in vitro. Hence, inhibition of bacterial adhesion by
PDF
Album
Supp Info
Full Research Paper
Published 01 Feb 2013

A new family of four-ring bent-core nematic liquid crystals with highly polar transverse and end groups

  • Kalpana Upadhyaya,
  • Venkatesh Gude,
  • Golam Mohiuddin and
  • Rao V. S. Nandiraju

Beilstein J. Org. Chem. 2013, 9, 26–35, doi:10.3762/bjoc.9.4

Graphical Abstract
  • azobenzene or salicylideneimine or phenylbenzoate unit in one of the arms of the bent molecule by a polar cyanobiphenyl moiety lends stiffness to the molecule with a strong dipole moment in the lateral direction. The realization of such a molecular architecture leads to a reduction in rotational disorder as
PDF
Album
Full Research Paper
Published 07 Jan 2013

Amino-substituted diazocines as pincer-type photochromic switches

  • Hanno Sell,
  • Christian Näther and
  • Rainer Herges

Beilstein J. Org. Chem. 2013, 9, 1–7, doi:10.3762/bjoc.9.1

Graphical Abstract
  • the thermodynamically more stable cis isomer the lone pairs of the amino nitrogen atoms point towards each other, and in the trans form they point in opposite directions. The distance between the amino nitrogen atoms changes between 8 Å (cis) and 11 Å (trans isomer). Keywords: azobenzene; diazocine
  • as directed motion at the molecular level [2][3], the geometry change and the force induced during cis–trans isomerization has to be coupled to the environment. In the macroscopic world, therefore, machines are made from stiff materials. Azobenzene, however, is a rather floppy molecule. Both phenyl
  • conformational motion. The first and probably most simple measure to make azobenzene stiffer would be to prevent the phenyl groups from rotating. Connecting both rings with each other via an alkane bridge is probably the most straightforward way to achieve that. Such a molecule, 5,6-dihydrodibenzo[c,g][1,2
PDF
Album
Supp Info
Full Research Paper
Published 02 Jan 2013

A bisazobenzene crosslinker that isomerizes with visible light

  • Subhas Samanta,
  • Harris I. Qureshi and
  • G. Andrew Woolley

Beilstein J. Org. Chem. 2012, 8, 2184–2190, doi:10.3762/bjoc.8.246

Graphical Abstract
  • Subhas Samanta Harris I. Qureshi G. Andrew Woolley Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON, M5S 3H6, Canada; telephone: (416) 978-0675, fax: (416) 978-8775 10.3762/bjoc.8.246 Abstract Background: Large conformational and functional changes of azobenzene
  • -modified biomolecules require longer azobenzene derivatives that undergo large end-to-end distance changes upon photoisomerization. In addition, isomerization that occurs with visible rather than UV irradiation is preferred for biological applications. Results: We report the synthesis and characterization
  • of a new crosslinker in which a central piperazine unit links two azobenzene chromophores. Molecular modeling indicates that this crosslinker can undergo a large change in end-to-end distance upon trans,trans to cis,cis isomerization. Photochemical characterization indicates that it does isomerize
PDF
Album
Supp Info
Full Research Paper
Published 14 Dec 2012

Cyclodextrin-induced host–guest effects of classically prepared poly(NIPAM) bearing azo-dye end groups

  • Gero Maatz,
  • Arkadius Maciollek and
  • Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 1929–1935, doi:10.3762/bjoc.8.224

Graphical Abstract
  • ]. Several reports are available on the preparation and properties of thermally responsive polyacrylamides containing azobenzene or stilbene dyes in the side chain [3][14]. Furthermore, the interaction of dye-containing polymers with CD in water is of some interest, because of their external, light-induced
PDF
Album
Supp Info
Full Research Paper
Published 14 Nov 2012

Design and synthesis of a photoswitchable guanidine catalyst

  • Philipp Viehmann and
  • Stefan Hecht

Beilstein J. Org. Chem. 2012, 8, 1825–1830, doi:10.3762/bjoc.8.209

Graphical Abstract
  • photochromic properties demonstrated the reversible switchability of its photosensitive azobenzene moiety. Its activity in the ring-opening polymerization (ROP) of rac-lactide was investigated as well. The obtained results are discussed, and an additional guanidine was synthesized and utilized in the ROP of
  • hydrogen bonds to an acceptor (A) and activated by light-triggered dissociation of such intramolecular hydrogen bonds (Scheme 2). Herein, we report the synthesis of the first photoswitchable guanidine, as well as its photochromic behavior. Upon irradiation, the incorporated azobenzene is supposed to
  • was converted by known procedures into its corresponding nitroso derivative 7 [19], followed by a Mills coupling with 4-aminoacetophenone (8) to give azobenzene 9 in 93% yield over two steps. Nitroazobenzene 9 was transformed into its amino derivative 10 by catalytic hydrogenation. Note that under the
PDF
Album
Supp Info
Video
Full Research Paper
Published 24 Oct 2012

Metal–ligand multiple bonds as frustrated Lewis pairs for C–H functionalization

  • Matthew T. Whited

Beilstein J. Org. Chem. 2012, 8, 1554–1563, doi:10.3762/bjoc.8.177

Graphical Abstract
  • of isocyanates to ruthenium(II) silylenes [58] (Scheme 8). These complexes do not react with nonpolar substrates (although a possible cycloaddition with azobenzene was reported), and the overall cycloaddition was found to proceed through initial nucleophilic attack at an electrophilic silylene
PDF
Album
Supp Info
Review
Published 18 Sep 2012

Mannose-decorated cyclodextrin vesicles: The interplay of multivalency and surface density in lectin–carbohydrate recognition

  • Ulrike Kauscher and
  • Bart Jan Ravoo

Beilstein J. Org. Chem. 2012, 8, 1543–1551, doi:10.3762/bjoc.8.175

Graphical Abstract
  • (intervesicular binding) and hence cause vesicle aggregation. We have previously observed this effect for homobifunctional guest molecules equipped with two azobenzene, methylbenzoyl, or tert-butylbenzyl groups [32][33][34]. It should be noted that in the case of guest 3 the aggregation due to cross-linking is
PDF
Album
Supp Info
Full Research Paper
Published 17 Sep 2012

Cation affinity numbers of Lewis bases

  • Christoph Lindner,
  • Raman Tandon,
  • Boris Maryasin,
  • Evgeny Larionov and
  • Hendrik Zipse

Beilstein J. Org. Chem. 2012, 8, 1406–1442, doi:10.3762/bjoc.8.163

Graphical Abstract
  • -position are significantly more effective than aryl substituents in stabilizing the pyridinium ions formed through acetyl cation addition. Photo-switchable 3,4-diaminopyridines including a diazo moiety are potentially useful as special-purpose catalysts. The azobenzene substituent itself is electron
PDF
Album
Supp Info
Full Research Paper
Published 31 Aug 2012

Control over molecular motion using the cistrans photoisomerization of the azo group

  • Estíbaliz Merino and
  • María Ribagorda

Beilstein J. Org. Chem. 2012, 8, 1071–1090, doi:10.3762/bjoc.8.119

Graphical Abstract
  • . This transformation induces a molecular movement and a significant geometric change, therefore the azobenzene unit is an excellent candidate to build dynamic molecular devices. We describe selected examples of systems containing an azobenzene moiety and their motions and geometrical changes caused by
  • external stimuli. Keywords: azobenzenes; molecular switches; nanomachines; photoisomerization; Review This review is based on an article published in 2009 in Anales de Química (Real Sociedad Española de Química) [1]. Azobenzene was described for the first time in 1834 [2] and one century later, in 1937
  • , G. S. Hartley published a study of the influence of light on the configuration of N=N double bonds [3]. The exposure of a solution of azobenzene in acetone to light allowed the discovery of the cis isomer. This finding was the starting point of the development of one of the best organic molecular
PDF
Album
Review
Published 12 Jul 2012

Recent advances towards azobenzene-based light-driven real-time information-transmitting materials

  • Jaume García-Amorós and
  • Dolores Velasco

Beilstein J. Org. Chem. 2012, 8, 1003–1017, doi:10.3762/bjoc.8.113

Graphical Abstract
  • fast relaxation times for azobenzene-based photochromic molecular switches is still a challenge. This review focuses on the most recent achievements on azobenzene-based light-driven real-time information-transmitting systems. Besides, the main relationships between the structural features of the azo
  • applications are certainly azobenzenes. Azobenzene, a photochromic T-type system, exhibits a reversible isomerisation process between its trans and cis isomers of different stability. In this process, the photoreaction simply causes the rearrangement of the electronic and nuclear structure of the molecule
  • radicals may occur and dediazotation can be observed [19][20]. Azobenzene-based photochromic systems are under kinetic control; that is, after a photochemical conversion, whose rate depends mainly on the intensity of the excitation beam, the spontaneous thermal back reaction occurs. While the photo-induced
PDF
Album
Review
Published 04 Jul 2012

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

Graphical Abstract
  • photoswitchable components in nucleic acids and are suitable for the control of a variety of different biological functions. The photoinduced cis–trans isomerization of azobenzene nucleosides can reversibly switch between the formation and dissociation of DNA duplexes [14][15][16][17], photoregulate DNA
PDF
Album
Video
Full Research Paper
Published 20 Jun 2012

Building photoswitchable 3,4'-AMPB peptides: Probing chemical ligation methods with reducible azobenzene thioesters

  • Gehad Zeyat and
  • Karola Rück-Braun

Beilstein J. Org. Chem. 2012, 8, 890–896, doi:10.3762/bjoc.8.101

Graphical Abstract
  • two regioisomeric azobenzene building blocks 3,4'-AMPB thioester 1b and 4,4'-AMPB thioester 2b were employed in the ligation reactions. While 4,4'-AMPB requires the 4,5,6-trimethoxy-2-mercaptobenzyl auxiliary to minimize reduction of the diazene unit, 3,4'-AMPB can be used in combination with the
  • azoproteins for ambitious biophysical studies, and also for intracellular applications. In this respect, an increased and predictable stability of azobenzene building blocks under reducing conditions seems to be a prerequisite in light of synthetic challenges, but also when considering the reducing
  • intracellular environment. We recently reported on the synthesis, properties and applications of a series of novel azobenzene ω-amino acids, with a preference for meta-substitution patterns. Our purpose was amongst other things (i) to increase flexibility, and (ii) to suppress resonance effects in order to
PDF
Album
Supp Info
Video
Full Research Paper
Published 18 Jun 2012

Intramolecular bridges formed by photoswitchable click amino acids

  • Christian Hoppmann,
  • Ronald Kühne and
  • Michael Beyermann

Beilstein J. Org. Chem. 2012, 8, 884–889, doi:10.3762/bjoc.8.100

Graphical Abstract
  • presence of glutathione as an additional thiol the click reaction of the PSCaa occurs intramolecularly with the cysteine rather than with the glutathione, indicating that the click reaction may be used even under reducing conditions occurring in living cells. Keywords: azobenzene; helical conformation
  • ; isomerization; molecular switches; photoswitchable click amino acid; thiol–ene click; Introduction Photoswitchable bridges that are site-specifically incorporated into proteins allow the conformation and activity of proteins to be modulated by light. In contrast to common bivalent thiol reactive azobenzene
  • switches [1][2][3][4][5], the PSCaa described here (Scheme 1) is an α-amino acid containing, besides an azobenzene unit, a vinyl function that can react specifically with a cysteine within a putative conformational domain of a peptide or a protein by light-induced thiol–ene click reaction [6][7][8][9]. The
PDF
Album
Supp Info
Letter
Published 13 Jun 2012

meta-Oligoazobiphenyls – synthesis via site-selective Mills reaction and photochemical properties

  • Raphael Reuter and
  • Hermann A. Wegner

Beilstein J. Org. Chem. 2012, 8, 877–883, doi:10.3762/bjoc.8.99

Graphical Abstract
  • revealed that the overall degree of switching was independent of the connected azo-units. However, one of the azobonds in the bis-azobiphenyl is isomerized preferentially despite the high structural similarity. Keywords: azobenzene; cross-coupling reaction; foldamer; molecular switches; photochromism
  • ; Introduction The possibility to control structures on the molecular level in a reversible manner by using an external stimulus has fascinated scientists for a long time. One of the earliest reports on a molecular entity that can be influenced in this way concerns the azobenzene scaffold. Since this discovery
  • by Hartley in 1937 [1] many more compounds showing such a photochromism have been reported [2]. However, the azobenzene moiety still remains one of the most popular “work horses” in this respect [3][4][5][6]. The reason can probably be found in its relatively easy synthetic accessibility combined
PDF
Album
Supp Info
Full Research Paper
Published 13 Jun 2012

Molecular switches and cages

  • Dirk Trauner

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

Graphical Abstract
  • (Rück-Braun, Hoppmann). Two reviews discuss cis-azobenzenes with rapid thermal isomerization kinetics (Velasco), and highlight the azobenzene moiety as one of the smallest light-driven molecular motors conceivable (Merino). Issues of bistability are also addressed in an account on shape-persistent
PDF
Video
Editorial
Published 13 Jun 2012

Azobenzene dye-coupled quadruply hydrogen-bonding modules as colorimetric indicators for supramolecular interactions

  • Yagang Zhang and
  • Steven C. Zimmerman

Beilstein J. Org. Chem. 2012, 8, 486–495, doi:10.3762/bjoc.8.55

Graphical Abstract
  • Yagang Zhang Steven C. Zimmerman Department of Chemistry, 600 South Mathews Avenue, University of Illinois, Urbana, IL 61801, USA 10.3762/bjoc.8.55 Abstract The facile coupling of azobenzene dyes to the quadruply hydrogen-bonding modules 2,7-diamido-1,8-naphthyridine (DAN) and 7-deazaguanine urea
  • (DeUG) is described. The coupling of azobenzene dye 2 to mono-amido DAN units 4, 7, and 9 was effected by classic 4-(dimethylamino)pyridine (DMAP)-catalyzed peptide synthesis with N-(3-dimethylaminopropyl)-N’-ethyl carbodiimide hydrochloride (EDC) as activating agent, affording the respective amide
  • products 5, 8, and 10 in 60–71% yield. The amide linkage was formed through either the aliphatic or aromatic ester group of 2, allowing both the flexibility and absorption maximum to be tuned. Azobenzene dye 1 was coupled to the DeUG unit 11 by Steglich esterification to afford the product amide 12 in 35
PDF
Album
Supp Info
Full Research Paper
Published 02 Apr 2012

Liquid-crystalline nanoparticles: Hybrid design and mesophase structures

  • Gareth L. Nealon,
  • Romain Greget,
  • Cristina Dominguez,
  • Zsuzsanna T. Nagy,
  • Daniel Guillon,
  • Jean-Louis Gallani and
  • Bertrand Donnio

Beilstein J. Org. Chem. 2012, 8, 349–370, doi:10.3762/bjoc.8.39

Graphical Abstract
  • to emphasise the wider applicability of this approach to nanohybrid science. Fundamental studies into the photochemical activity of lipophilic azobenzene- and stilbene thiols (10, Figure 12) on Au NPs surfaces were reported [66], which indicated a chromophore-to-NP distance dependence of the
  • photoisomerisation and photodimerisation efficiency in these systems. Interesting examples of the potential application of this type of approach were shown by the grafting of similar azobenzene ligands 11 (Figure 12) to the surfaces of γ-Fe2O3 [67] and FePt [68] NPs, which exhibited a photoswitchable change in
PDF
Album
Review
Published 08 Mar 2012

Continuous proline catalysis via leaching of solid proline

  • Suzanne M. Opalka,
  • Ashley R. Longstreet and
  • D. Tyler McQuade

Beilstein J. Org. Chem. 2011, 7, 1671–1679, doi:10.3762/bjoc.7.197

Graphical Abstract
  • , and finally azobenzene by product disproportionation [53][54][55]. Byproduct suppression is both solvent and temperature dependent. Hayashi reported that when the reaction is performed at room temperature in acetonitrile with 30 mol % proline, the reaction is complete in 10 min, but achieves only 29
PDF
Album
Supp Info
Full Research Paper
Published 14 Dec 2011

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

Graphical Abstract
  • ′-deoxyribose substitutes by influencing the stacking orientation of an attached azobenzene dye. The configuration of the linker decides if the dye protrudes towards the major or minor groove, which subsequently leads to an enhanced or diminished stability of the whole DNA duplex [42]. Herein, we want to
PDF
Album
Full Research Paper
Published 09 Feb 2010
Other Beilstein-Institut Open Science Activities