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Search for "photoswitching" in Full Text gives 48 result(s) in Beilstein Journal of Organic Chemistry.
Effect of a photoswitchable rotaxane on membrane permeabilization across lipid compositions
Beilstein J. Org. Chem. 2025, 21, 2498–2512, doi:10.3762/bjoc.21.192
- % (irradiated). Moreover, gel-phase DPPC bilayers also exhibited an increase in release from 7% to 14%. On the contrary, highly fluid pure EYPC bilayers showed high baseline release upon rotaxane incorporation (64%), with photoswitching producing only a slight increase (70%), as most dye was released within the
- first minutes of rotaxane insertion. Likewise, azobenzene photoswitching did not induce permeabilization in the more rigid and thicker EYPC/Chol 6:4 bilayers, which showed minimal release (5%). Furthermore, we discovered that when the unthreaded axle is irradiated with light, an unknown, irreversible
- permeabilization in bilayers of varying rigidity and whether membrane phase influences its photoswitching behavior. To address these questions, we investigated the light-induced switching of rotaxane 1 in large unilamellar vesicles (LUVs) composed of lipids representative of distinct membrane phases. Membrane
Rotaxanes with integrated photoswitches: design principles, functional behavior, and emerging applications
Beilstein J. Org. Chem. 2025, 21, 2345–2366, doi:10.3762/bjoc.21.179
- regulating the macrocycle’s position and, when appropriate, its shuttling rate. This section highlights representative examples featuring the most widely used photoswitches. Acridane Acridane photoswitching involves its photoheterolysis, generating a positively charged acridinium and an alkoxide, typically a
- reported the first [3]rotaxane with three azobenzene units in the axle and two α-cyclodextrins as the macrocycle. The rotaxane was obtained as a single stereoisomer, where the two narrow rings of the cyclodextrin point to each other. Although no photoswitching studies were conducted, 1H NMR results showed
- stoppers. The molecular motion of the macrocycle during azobenzene photoswitching was utilized to demonstrate controllable and reversible shape transformation behaviors and to perform weightlifting and cargo transporting tasks (Figure 5). Therefore, these rotaxanes highlight their potential in applications
Pd-catalyzed dehydrogenative arylation of arylhydrazines to access non-symmetric azobenzenes, including tetra-ortho derivatives
Beilstein J. Org. Chem. 2025, 21, 2234–2242, doi:10.3762/bjoc.21.170
- of applications, including molecular switches, sensors, and light-controlled materials [1][2][3][4][5][6][7][8]. The photoswitching behavior arises from the reversible photoisomerization between the E- and Z-forms of the azobenzene chromophore, driven by the isomerization of the N–N double bond. This
- photoswitching event involves a molecular size reduction between the E- and Z isomers, thereby driving structural changes that enable applications in molecular machines, biological allosteric modulators, and advanced functional materials (Figure 1a) [9][10][11]. Despite the widespread interest in azobenzenes
Photoswitches beyond azobenzene: a beginner’s guide
Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143
- detailed view on photoswitches, such as in-depth analysis of photoswitching processes [9], their application into smart materials and biological systems [10], and the application in aqueous environments [2], we refer the interested reader to further reviews on these topics. Review Azoheteroarenes
- of the nπ* bands, which are used in the photoswitching process, are increased, leading to higher PSSs and higher excitation wavelengths, alongside with an excellent quantum yield in both directions. The bridge is also accountable for the much faster response to irradiation with respect to azobenzene
- mono-N-substituted indigos which were also able to isomerise, despite the presence of one hydrogen atom, capable of proton transfer. Only rather electron-neutral substituents show photoswitching to some extent, and the thermal half-lives are, in general, very short. Interestingly, low amounts of water
Azobenzene protonation as a tool for temperature sensing
Beilstein J. Org. Chem. 2025, 21, 1528–1534, doi:10.3762/bjoc.21.115
- changes in their absorption and photochemical properties. While azobenzene protonation has been recently used as a tool in photoswitching studies, the factors influencing protonation itself have received little attention. Here, we report a strong temperature dependence of azobenzene protonation in 1,2
Highly distinguishable isomeric states of a tripodal arylazopyrazole derivative on graphite through electron/hole-induced switching at ambient conditions
Beilstein J. Org. Chem. 2025, 21, 1496–1507, doi:10.3762/bjoc.21.112
- isomer of azobenzene (AB) is a few days. Arylazopyrazole-based molecular switches are one of the profoundly explored systems in recent times due to their superior bidirectional photoswitching and long half-life (over a thousand days at room temperature) of Z isomers. Herein, we utilize an efficient solid
- imparted quantitative and reversible photoswitching [20][21]. The long-term photoswitching stability and tunable half-lifes of Z isomers of azopyrazole-based switches [20][21][22] have made their way to several applications in thermal energy storage [23], photoswitchable inhibitor [24], photoswitchable
- switchable probe for light-driven reversible printing and erasing applications [29]. Besides exhibiting excellent photoswitching in solution phase, the tripodal photoswitches exhibit extended half-life of the ZZZ isomer in the solid-state as well [22][29]. The overall efficiency of the molecular switch could
Substituent effects in N-acetylated phenylazopyrazole photoswitches
Beilstein J. Org. Chem. 2025, 21, 830–838, doi:10.3762/bjoc.21.66
- straightforward development for specific applications. In this work, we synthesized novel N-acylpyrazole-based photoswitches and conducted a comparative study with 33 phenylazopyrazoles, comparing their photoswitching properties and the impact of electronic effects. Using UV–vis and NMR spectroscopy, we
- these, azo-photoswitches based on a 1,3,5-trimethylpyrazole ring (phenylazopyrazole; PAP) became particularly popular, showing almost quantitative back and forward photoswitching and high thermal stability [31]. Moreover, 1H-pyrazole derivatives [32] and arylazopyrazolium [33] compounds were
- , we were interested to study the photoswitching properties of eleven novel N-acetylated analogous NAc-PAPs and the influence of substituent effects. Furthermore, we compared their photochromism with a set of 22 known N-methylated (NMe-) and unfunctionalized (NH-) PAPs in moderate to good yields (66–85
Synthesis and photoinduced switching properties of C7-heteroatom containing push–pull norbornadiene derivatives
Beilstein J. Org. Chem. 2025, 21, 807–816, doi:10.3762/bjoc.21.64
- . Photoswitching The photoswitching of the NBDs to corresponding QCs was monitored by UV–vis and 1H NMR spectroscopy. With increasing electronegativity of the bridge-atom, a slight bathochromic shift in the absorption spectra of the parent NBD precursors O-NBD1 and N-NBD1 was found (Figure 2a and 2c). For the
Orthogonal photoswitching of heterobivalent azobenzene glycoclusters: the effect of glycoligand orientation in bacterial adhesion
Beilstein J. Org. Chem. 2025, 21, 736–748, doi:10.3762/bjoc.21.57
- glycophotoswitches in their different isomeric states led to new insights into the role of ligand orientation in carbohydrate recognition. The experimental results were underpinned by molecular modeling. Keywords: azobenzene glycoconjugates; carbohydrate recognition; docking; FimH; orthogonal photoswitching
- conjugated to the 3- and the 6-position of a methyl mannoside scaffold (Figure 1, 1 (6βGlc3αMan)) [24]. Orthogonal photoswitching of the two glycoantennas is guaranteed by (i) ortho-fluorination of one azobenzene moiety and (ii) S-azobenzene versus O-azobenzene conjugation, resulting in significantly shifted
- Table 1 shows that the PSS values of the bis-azobenzene glycoclusters 1 and 2 are in a similar range. Furthermore, the glycoazobenzene antennas comprised in 1 and 2 show a similar switching behavior as the individual antennas 6αMan 3, 6βGlc 4, and 3αMan 5. Wavelength-selective photoswitching of 2 as
Effect of substitution position of aryl groups on the thermal back reactivity of aza-diarylethene photoswitches and prediction by density functional theory
Beilstein J. Org. Chem. 2025, 21, 242–252, doi:10.3762/bjoc.21.16
- -withdrawing substituents on the N-aryl moieties enhanced the thermal stability of the Z-isomers while maintaining the advantageous photoswitching properties upon irradiation with red light [52]. The effect of substituents on the thermal cis–trans isomerization of azobenzenes has also been widely studied, and
Understanding X-ray-induced isomerisation in photoswitchable surfactant assemblies
Beilstein J. Org. Chem. 2024, 20, 2005–2015, doi:10.3762/bjoc.20.176
- ]. However, the potential scope for Azo in practice is limited by its incomplete photoswitching to the metastable isomer in the PSS and its rapid thermal reversion to the E isomer [12][13]. To tackle this, arylazopyrazoles (AAPs) have emerged as promising alternatives, where one of the phenyl rings of Azo is
- replaced by a pyrazole, which improves several aspects of their performance, including quantitative photoswitching between isomers and significantly enhanced thermal stability of the Z isomer [13][14][15]. This has led to recent reports on the integration of AAPs into surfactants to form systems with
Supramolecular assemblies of amphiphilic donor–acceptor Stenhouse adducts as macroscopic soft scaffolds
Beilstein J. Org. Chem. 2024, 20, 1590–1603, doi:10.3762/bjoc.20.142
- cycle (Figure S1a and S1b, Supporting Information File 1). In contrast, the previously studied reversibility of the photoswitching of DA10 had revealed 10% absorbance decreases per cycle [37], indicating a mild improvement to the fatigue resistance of DA11. To further investigate the photostability and
- feasible photoreversibility of DA7 and DA6 for five additional photoswitching cycles. However, a more significant fatigue effect was observed in DA7 (Figure S1c and S1d, Supporting Information File 1) and DA6 (Figure S1e and S1f, Supporting Information File 1), with 15% absorbance decline per cycle. As a
Photoswitchable glycoligands targeting Pseudomonas aeruginosa LecA
Beilstein J. Org. Chem. 2024, 20, 1486–1496, doi:10.3762/bjoc.20.132
- ] or to mannosyl azobenzene-modified human cells [21] through photoswitching the orientation of the attached mannoside [22]. Photoswitchable glycooligomers [23] or glycodendrimers [24] have been investigated for the inhibition of PA lectin PA-IL or LecA and LecB. A variation of the IC50 value by a
- respectively 71%, 41%, and 37% total yields (Scheme 1). Photophysical characterization The photoswitching properties of galactosyl azobenzenes 1–5 were realized in water or in Tris buffer containing 5 to 10% DMSO, in accordance with the biophysical evaluation conditions by using ITC. All these compounds
- ). The S-galactosyl azobenzenes 3–5 also displayed excellent photoswitching properties, with a red shift for the π→π* transition (λmax = 348–364 nm) compared to the O-galactosyl derivatives (Table 1, entries 5–8). However, the absorption coefficient and the thermostability of the Z-isomers are increased
Novel route to enhance the thermo-optical performance of bicyclic diene photoswitches for solar thermal batteries
Beilstein J. Org. Chem. 2024, 20, 1053–1068, doi:10.3762/bjoc.20.93
- by employing chemical photoswitches in molecular solar thermal (MOST) energy storage systems is a topic of appealing research interest. However, incorporating all the features desired for an ideal MOST system in a single photoswitching couple is challenging. Inspired by experimental synthesis, herein
- the most versatile solvent to exhibit the best photoswitching behaviour which is beneficial for real-life energy storage applications. Additionally, the stability and reversibility of the photoswitching system with elongated unsaturated bridges have also been assessed. By means of the studied
- the photoswitching cycle [8][9][10][11][12][13]. This enables the harvesting, conversion, and storage of solar energy into thermal energy via a reversible and closed photoswitching cycle. The photoswitching couple must exhibit distinct features to be applicable for solar energy harvesting and storage
Switchable molecular tweezers: design and applications
Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45
- allosterically regulated host–guest systems to catalysis or magnetic properties. Redox switchable molecular tweezers One of the cleanest stimuli for supramolecular switching is electron transfer. Besides photoswitching, the undeniable advantages of redox switching are the absence of chemical waste and the fact
Photochromic derivatives of indigo: historical overview of development, challenges and applications
Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23
- of prospective applications of indigo photoswitches. Keywords: indigoid dyes; photochemistry; photophysics; photoswitching; E–Z isomerization; Review Historical milestones in the development of photochromic indigo derivatives 1954: first reported photochromic indigo derivative – N,N'-diacetylindigo
- in the presence of water in organic solvent. In 2023, Huang, Hecht, Priimagi and co-workers provided the first study of the photoswitching of Ν,Ν'-derivatized indigos in polymer films of different rigidity and described the molecular design strategy allowing to improve the photoswitching performance
- within the polymer matrix [67]. Based on the obtained results, the authors are aiming to translate the photoswitching effect to the macroscopic level and to achieve the modulation of macroscopic properties of materials by red light. Conclusion From the first report on the photochromic N,N'-diacetylindigo
Azo-dimethylaminopyridine-functionalized Ni(II)-porphyrin as a photoswitchable nucleophilic catalyst
Beilstein J. Org. Chem. 2020, 16, 2119–2126, doi:10.3762/bjoc.16.179
- . reported on the photoswitching of the basicity of a piperidine nitrogen by reversible steric shielding of the nitrogen lone pair. The photoswitchable base was applied as a nucleophilic catalyst in the nitroaldol (Henry) reaction. Attached to a sterically demanding azobenzene unit, the lone pair was
Potent hemithioindigo-based antimitotics photocontrol the microtubule cytoskeleton in cellulo
Beilstein J. Org. Chem. 2020, 16, 125–134, doi:10.3762/bjoc.16.14
- hemithioindigo-based indanone-like tubulin inhibitors (HITubs) and optimised their cellular potency as antimitotic photopharmaceuticals. These HITubs feature reliable and robust visible-light photoswitching and high fatigue resistance. The use of the hemithioindigo scaffold also permitted us to employ a para
- , all-visible-light photoswitching. Results and Discussion Design strategy for HTIs The HTI-based colchicinoid HOTubs (e.g., HOTub-31) that we previously explored had the HTI photoswitch embedded inside a methoxylation pattern, such that one isomer obeyed the structure–activity relationship (SAR) of
- photopharmaceutical scaffold than the widely used azobenzene motif. While para-hydroxyazobenzenes feature negligibly short cis-to-trans thermal relaxation half- lives in aqueous media in the range of μs [24][25], probably making them unsuitable for robust photoswitching applications against intracellular targets
Reversible photoswitching of the DNA-binding properties of styrylquinolizinium derivatives through photochromic [2 + 2] cycloaddition and cycloreversion
Beilstein J. Org. Chem. 2020, 16, 111–124, doi:10.3762/bjoc.16.13
- coupling of its transition dipole moment with the ones of the DNA bases. Overall, these data revealed a loose binding of the cyclobutane derivative 4b to DNA through outside-edge binding of the ligand that enabled the association of one or two aromatic units in the DNA grooves. Photoswitching of the DNA
Light-controllable dithienylethene-modified cyclic peptides: photoswitching the in vivo toxicity in zebrafish embryos
Beilstein J. Org. Chem. 2020, 16, 39–49, doi:10.3762/bjoc.16.6
- embryotoxicity of dithienylethene-modified peptides upon photoswitching, using 19 analogues based on the β-hairpin scaffold of the natural membranolytic peptide gramicidin S. We established an in vivo assay in two variations (with ex vivo and in situ photoisomerization), using larvae of the model organism Danio
- , (iii) demonstrate photoswitching of the whole-body toxicity for the dithienylethene-modified peptides in vivo, (iv) re-analyze previous structure–toxicity relationship data, and (v) select promising candidates for potential clinical development. Keywords: diarylethene photoswitch; gramicidin S
- dilution steps. In the photoconversion experiments, in order to prevent spontaneous photoswitching of the ring-closed peptides by vis light, zebrafish embryos and peptides were kept in the dark before the first readout, and the vials were sealed to avoid evaporation of the embryonic medium (E3) at
Starazo triple switches – synthesis of unsymmetrical 1,3,5-tris(arylazo)benzenes
Beilstein J. Org. Chem. 2020, 16, 22–31, doi:10.3762/bjoc.16.4
- variety of unsymmetrical starazo species, starting from suitable dibromoazobenzenes. A preliminary investigation of the presented three-state switches by UV–vis and 1H NMR spectroscopy revealed that both derivatives 3a and 3b were capable of E→Z photoisomerization. However, no selective photoswitching
Synthesis and characterization of bis(4-amino-2-bromo-6-methoxy)azobenzene derivatives
Beilstein J. Org. Chem. 2019, 15, 3000–3008, doi:10.3762/bjoc.15.296
- in particular can form azonium ions under physiological conditions and exhibit red-light photoswitching. Here, we report the synthesis and characterization of two bis(4-amino-2-bromo-6-methoxy)azobenzene derivatives. These compounds form red-light-absorbing azonium ions, but only under very acidic
- azobenzenes – have recently been found to exhibit photoswitching properties suitable for in vivo use [8][9][10]. Typically, the formation of azonium ions from aminoazobenzenes occurs at pH < 3.5 [11][12], however, the pKa of the trans-azonium ion 1 is ca. 7.5 in aqueous solution (Figure 1) [9][10]. The
- isomerization with 720 nm light under physiological conditions [8]. While the photoswitching properties of 3 are suitable for the use in biological systems, the overall size of 3 may limit the possibilities for the use as a component of photopharmaceutical agents. Currently, most photopharmaceutical agents are
Design, synthesis and investigation of water-soluble hemi-indigo photoswitches for bioapplications
Beilstein J. Org. Chem. 2019, 15, 2822–2829, doi:10.3762/bjoc.15.275
- Daria V. Berdnikova Department Chemie–Biologie, Organische Chemie II, Universität Siegen, Adolf-Reichwein-Str. 2, 57076 Siegen, Germany 10.3762/bjoc.15.275 Abstract A series of hemi-indigo derivatives was synthesized and their photoswitching properties in aqueous medium were studied. The
- that allowed to obtain an RNA-binding hemi-indigo derivative with photoswitchable fluorescent properties. Keywords: hemi-indigo; molecular switches; photochromism; photoswitching; visible light; water solubility; Introduction The application of organic photochromes in biological systems is fraught
- with their poor solubility and reduced photoswitching efficiency in aqueous medium. In many cases, approaches to improve the water solubility by chemical modification of the photochromic scaffolds are not straightforward because the introduction of substituents often interferes with the desired
Chemical tuning of photoswitchable azobenzenes: a photopharmacological case study using nicotinic transmission
Beilstein J. Org. Chem. 2019, 15, 2812–2821, doi:10.3762/bjoc.15.274
- the cis-4FAB configuration (thermal half-life > 12 days at 37 °C in physiological buffer) and cis–trans photostationary states above 84%. Furthermore, the well-separated n–π* absorption bands of trans- and cis-4FAB allow facile photoswitching with visible light in two optical channels. A convergent 11
- photoswitching of 2 (Figure 5c, colored traces). The time between these sweeps was 3 min. Since we used full field illumination through the epi-fluorescence port of the microscope for our experiments, the light not only illuminates an area around the cell, but much of the volume of the puffer pipette reservoir
- neurotransmitters. We have synthesized a photoswitchable tetrafluoroazobenzene (4FAB) agonist of nicotinic acetylcholine receptors that is biologically inert at sub-millimolar levels in the cis AB configuration. Photoswitching of the chromophore on neurons with violet light rapidly activates inward currents. We
Photoreversible stretching of a BAPTA chelator marshalling Ca2+-binding in aqueous media
Beilstein J. Org. Chem. 2019, 15, 2801–2811, doi:10.3762/bjoc.15.273
- calcium upon acting on the conformation of the adjacent binding site, rendering it a stronger or weaker binder. Photoswitching was studied in pseudo-physiological conditions (pH 7.2, [KCl] = 100 mM) and dissociation constants for azobenzene cis- and trans-isomers have been determined (0.230 μM and 0.102
- EDTA) such that photoswitching would enhance or lower Ca2+ binding based on the state of the adjacent photoswitch. Photogeneration of a positive charge proximal to the BAPTA site is undoubtedly the most robust approach to provoke calcium cation release, while diminishing electron density on the
- affinity. Herein we describe the synthesis of 1, its photoswitching, and affinity changes between both forms in pseudo-physiological conditions, further rationalized by energy-minimized molecular modelling structures. Results and Discussion The synthetic pathway for the preparation of molecule 1 is shown
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