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

• crosslinker BPDBS, (4,4'-bis(4-(2-chloroacetamido)phenyl)diazenylbiphenyl-2,2'-disulfonate) (1, Scheme 1) [24]. This photoswitch can produce a minimum ~5 Å and a maximum ~23 Å end-to-end distance change upon trans–cis isomerization. It has a high absorption coefficient (45–60,000 M−1cm−1) and can produce up

• to ~80% trans–cis isomerization under favorable conditions. The suitability of this photoswitch for biological systems would be enhanced if the wavelengths required for photoisomerization were longer, so that UV light was not required. UV light is highly scattered by biological samples and can be a

• red-shifted compared to BPDBS with a maximum near 420 nm. The molar extinction coefficient for 2 was determined by 1H NMR coupled with UV–vis absorption spectra, to be 66,400 in DMSO at 428 nm, such that on a molar basis, the photoswitch is intensely colored. The spectra in aqueous solutions are pH

Control over molecular motion using the cis–trans photoisomerization of the azo group

• Estíbaliz Merino and
• María Ribagorda

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

• photoswitch is a part of a macromolecular structure. A variety of photosensitive devices, such as smart polymers [36][37], liquid crystals [38][39], intelligent enzymes [40], and various switches and molecular machines [41][42][43][44][45][46][47][48], have been developed by using the photochromic properties

• fluorescent dye close to the photoswitch giving rise to a fluorescence change upon isomerization. The introduction of azobenzene-modified biomolecules in zebrafish proved that the photochemistry of azobenzenes was similar in vivo and in vitro, and that appropriate azobenzenes could be stable in vivo for days

• results in a collective structural change in a certain direction. This cooperative molecular motion of SAMazo acts as a molecular lift capable of lifting one Hg drop deposited on the monolayer of azobenzenes. Furthermore, this device acts as a photoswitch of the current between the Au(111) layer and the

On the bromination of the dihydroazulene/vinylheptafulvene photo-/thermoswitch

• Virginia Mazzanti,
• Martina Cacciarini,
• Søren L. Broman,
• Christian R. Parker,
• Magnus Schau-Magnussen,
• Andrew D. Bond and
• Mogens B. Nielsen

Beilstein J. Org. Chem. 2012, 8, 958–966, doi:10.3762/bjoc.8.108

• ; photoswitch; vinylheptafulvene; Introduction 1,8a-Dihydroazulene-1,1-dicarbonitrile (DHA, 1) is a yellow photochromic compound, which undergoes a light-induced 10-electron retro-electrocyclization to a red-colored vinylheptafulvene (VHF) (Scheme 1) [1][2][3]. The VHF compound is formed as the s-cis conformer

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

• applied for switching the binding affinities of proteins and peptides [32] but are still rather unexplored with respect to nucleic acids. The advantage of this type of photoswitch is that back reaction (reopening of the central ring) requires light and cannot be achieved in a thermally induced way

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

• binding motif is associated with H5N1 influenza infections. We reasoned that the attachment of a photoswitch next to SXV PDZ-binding motifs would be a powerful strategy for exploring the function of these PDZ-binding peptide ligands in vitro and in vivo. For the synthetic ligation studies presented herein

• synthesis and evaluation of photoswitchable protein analogues, for example receptors with the photoswitch placed in the direct neighborhood of the specific C-terminal binding motif. Results and Discussion The azobenzene ω-amino-acid thioesters 1b and 2b were prepared by following and applying literature

A perfluorocyclopentene based diarylethene bearing two terpyridine moieties – synthesis, photochemical properties and influence of transition metal ions

• Falk Wehmeier and
• Jochen Mattay

Beilstein J. Org. Chem. 2010, 6, No. 53, doi:10.3762/bjoc.6.53

• diarylethene unit (3) can be obtained by lithiation of 3-bromo-2-methylbenzo[b]thiophene (1) followed by quenching with perfluorocyclopentene (2), according to the method described by Irie [12]. Electrophilic iodination leads to the diiodo photoswitch 4 (Scheme 1) [13][14]. We decided to use the diiodo switch