Complete ON/OFF Photoswitching of the Motility of a Nanobiomolecular Machine

Kumar, K. R. Sunil; Kamei, Takashi; Fukaminato, Tuyoshi; Tamaoki, Nobuyuki

doi:10.1021/nn5010342

Cited by 48 publications

(44 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…58 However, as the system became more electron rich, photobleaching was observed. This was not a problem for blue-absorbing (16) and cyan-absorbing compounds (17), but with the green-absorbing compound 18, color loss occurred in a few hours under ambient light.…”

Section: ■ Ortho Substitutionmentioning

confidence: 99%

Red-Shifting Azobenzene Photoswitches for in Vivo Use

et al. 2015

View full text Add to dashboard Cite

Recently, there has been a great deal of interest in using the photoisomerization of azobenzene compounds to control specific biological targets in vivo. These azo compounds can be used as research tools or, in principle, could act as optically controlled drugs. Such "photopharmaceuticals" offer the prospect of targeted drug action and an unprecedented degree of temporal control. A key feature of azo compounds designed to photoswitch in vivo is the wavelength of light required to cause the photoisomerization. To pass through tissue such as the human hand, wavelengths in the red, far-red, or ideally near infrared region are required. This Account describes our attempts to produce such azo compounds. Introducing electron-donating or push/pull substituents at the para positions delocalizes the azobenzene chromophore and leads to long wavelength absorption but usually also lowers the thermal barrier to interconversion of the isomers. Fast thermal relaxation means it is difficult to produce a large steady state fraction of the cis isomer. Thus, specifically activating or inhibiting a biological process with the cis isomer would require an impractically bright light source. We have found that introducing substituents at all four ortho positions leads to azo compounds with a number of unusual properties that are useful for in vivo photoswitching. When the para substituents are amide groups, these tetra-ortho substituted azo compounds show unusually slow thermal relaxation rates and enhanced separation of n-π* transitions of cis and trans isomers compared to analogues without ortho substituents. When para positions are substituted with amino groups, ortho methoxy groups greatly stabilize the azonium form of the compounds, in which the azo group is protonated. Azonium ions absorb strongly in the red region of the spectrum and can reach into the near-IR. These azonium ions can exhibit robust cis-trans isomerization in aqueous solutions at neutral pH. By varying the nature of ortho substituents, together with the number and nature of meta and para substituents, long wavelength switching, stability to photobleaching, stability to hydrolysis, and stability to reduction by thiols can all be crafted into a photoswitch. Some of these newly developed photoswitches can be used in whole blood and show promise for effective use in vivo. It is hoped they can be combined with appropriate bioactive targets to realize the potential of photopharmacology.

show abstract

Section: ■ Ortho Substitutionmentioning

confidence: 99%

Red-Shifting Azobenzene Photoswitches for in Vivo Use

et al. 2015

View full text Add to dashboard Cite

show abstract

“…[13a] Light irradiation is a highly employed stimulus applied for the control of molecular machinery. [14] Jointly with fumaramide-maleamide systems, [15] azobenzene derivatives [16] or alkenes [17] have been widely employed as photoisomerizable units, among others, as components in artificial machines.…”

Section: Introductionmentioning

confidence: 99%

“…16.61 mg, 80 %); 1 H NMR (400 MHz, CDCl 3 ): δ = 7.37-7.20 (m, 10H),6.44-6.37 (m, 2H), 4.61 (s, 2H′), 4.49 (s, 2H), 3.39-3.24 (m, 4H), 1.70-1.59 (m, 4H), 0.96-0.89 (m, 6H) ppm. 13 C NMR (100 MHz, CDCl 3 ): δ = 167.7 (CO), 166.4 (CO), 136.9 (C), 136.6 (C), 130.5 (CH), 129.3 (CH), 129.0 (CH), 128.7 (CH), 128.6 (CH), 127.7 (CH), 127.4 (CH), 127.2 (CH), 50.8 (CH 2 ), 50.3 (CH 2 ), 47.5 (CH 2 ), 47.2 (CH 2 ), 22.4 (CH 2 ), 20.9 (CH 2 ), 11.6 (CH 3 ), 11.4 (CH 3 ) ppm.…”

mentioning

confidence: 99%

Thermally and Photochemically Induced Dethreading of Fumaramide‐Based Kinetically Stable Pseudo[2]rotaxanes

et al. 2019

View full text Add to dashboard Cite

The thermally and photochemically induced dethreading of a series of pseudo[2]rotaxanes bearing tetraalkyl‐substituted fumaramide axles and polyamide macrocycles is reported herein. The length of the alkyl chains at the ends of the thread, the void size, and flexibility of the macrocycle and the intercomponent interactions are critical for a satisfactory dethreading process. 1H NMR kinetic experiments were carried out in order to calculate the rate constants of the thermal dethreading processes and stabilities of the rotaxanes, by comparing with the similar data for the deslipping of the succinamide surrogates. The deslipping reaction occurs faster with the fumaramide systems than succinamide ones. The incorporation of adamantane moieties into the polyamide macrocycle drastically slowed down the disconnecting process. Furthermore, interlocked systems with dipropylamino groups as stoppers experienced a rapid dethreading when irradiated under UV‐light, a process triggered by the fumaramide–maleamide isomerization. In this case, the n‐propyl groups are not bulky enough to keep together both components as the number of hydrogen bonds between thread and macrocycle is halved in the maleamide systems.

show abstract

“…A C C E P T E D ACCEPTED MANUSCRIPT 4 for applications in optical data storage,43 holographic surface relief grating (SRG) [44][45][46], liquid crystal display [47,48], optical switching [49,50] and so on. Moreover, azobenzene polymers can also be used in the new area of light stimuli-responsive materials [51][52][53][54] with fascinating and advantageous properties for potential uses especially in remote activation, reversible incalculability, and in precisely controlling wavelength, illuminated area, direction, and intensity.…”

Section: A N U S C R I P Tmentioning

confidence: 99%