A General Strategy for Visible-Light Decaging Based on the Quinone Trimethyl Lock

2017 ◽  
Vol 139 (13) ◽  
pp. 4655-4658 ◽  
Author(s):  
David P. Walton ◽  
Dennis A. Dougherty
Keyword(s):  
Visible Light ◽  
General Strategy ◽  
Trimethyl Lock

Visible-Light Photosensitized Aryl and Alkyl Decarboxylative Carbon-Heteroatom and Carbon-Carbon Bond Formations

2019 ◽  
Author(s):  
Tuhin Patra ◽  
Satobhisha Mukherjee ◽  
Jiajia Ma ◽  
Felix Strieth-Kalthoff ◽  
Frank Glorius
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Alkyl Radical ◽  
General Strategy ◽  
Alkyl Radicals ◽  
Bond Forming ◽  
Radical Trapping ◽  
Carbon Carbon Bond ◽  
Radical Generation ◽  
Trapping Agent

<sub>A general strategy to access both aryl and alkyl radicals by photosensitized decarboxylation of the corresponding carboxylic acids esters has been developed. An energy transfer mediated homolysis of unsymmetrical sigma-bonds for a concerted fragmentation/decarboxylation process is involved. As a result, an independent aryl/alkyl radical generation step enables a series of key C-X and C-C bond forming reactions by simply changing the radical trapping agent.</sub>

scholarly journals A general strategy for visible-light decaging based on the quinone cis-alkenyl lock

2019 ◽  
Vol 55 (34) ◽  
pp. 4965-4968 ◽  
Author(s):  
David P. Walton ◽  
Dennis A. Dougherty
Keyword(s):  
Visible Light ◽  
Protecting Groups ◽  
General Strategy ◽  
Thermal Cyclization ◽  
Coumaric Acid ◽  
Photoremovable Protecting Groups

Combining the fast thermal cyclization of o-coumaric acid derivatives with the intramolecular photoreduction of quinones gives new visible-light photoremovable protecting groups absorbing well above 450 nm.

scholarly journals Single-atom replacement as a general approach towards visible-light/near-infrared heavy-atom-free photosensitizers for photodynamic therapy

2020 ◽  
Vol 11 (26) ◽  
pp. 6701-6708 ◽  
Author(s):  
Juan Tang ◽  
Lushun Wang ◽  
Axel Loredo ◽  
Carson Cole ◽  
Han Xiao
Keyword(s):  
Photodynamic Therapy ◽  
Oxygen Atom ◽  
Visible Light ◽  
Near Infrared ◽  
Heavy Atom ◽  
Single Atom ◽  
General Strategy ◽  
Nir Light ◽  
Fluorescent Molecules

Thio-based photosensitizer: a general strategy for preparing visible/NIR light absorbing heavy-atom-free photosensitizers was developed by performing a simple sulfur-for-oxygen atom substitution within existing fluorescent molecules.

Visible-Light Photosensitized Aryl and Alkyl Decarboxylative Carbon-Heteroatom and Carbon-Carbon Bond Formations

2019 ◽  
Author(s):  
Frank Glorius ◽  
Tuhin Patra ◽  
Satobhisha Mukherjee ◽  
Jiajia Ma ◽  
Felix Strieth-Kalthoff
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Alkyl Radical ◽  
General Strategy ◽  
Alkyl Radicals ◽  
Bond Forming ◽  
Radical Trapping ◽  
Carbon Carbon Bond ◽  
Radical Generation ◽  
Trapping Agent

<sub>A general strategy to access both aryl and alkyl radicals by photosensitized decarboxylation of the corresponding carboxylic acids esters has been developed. An energy transfer mediated homolysis of unsymmetrical sigma-bonds for a concerted fragmentation/decarboxylation process is involved. As a result, an independent aryl/alkyl radical generation step enables a series of key C-X and C-C bond forming reactions by simply changing the radical trapping agent.</sub>

Visible-light-mediated cleavage of polymer chains under physiological conditions via quinone photoreduction and trimethyl lock

2017 ◽  
Vol 53 (89) ◽  
pp. 12076-12079 ◽  
Author(s):  
Vinh X. Truong ◽  
Fanyi Li ◽  
Francesca Ercole ◽  
John S. Forsythe
Keyword(s):  
Visible Light ◽  
Polymer Chains ◽  
Physiological Conditions ◽  
Trimethyl Lock

We introduce a click and visible-light triggered unclick approach via thio-bromo reaction and hydroquinone photoreduction/trimethyl lock cleavage for polymer modifications.

Visible-Light Photosensitized Aryl and Alkyl Decarboxylative Carbon-Heteroatom and Carbon-Carbon Bond Formations

2019 ◽  
Author(s):  
Frank Glorius ◽  
Tuhin Patra ◽  
Satobhisha Mukherjee ◽  
Jiajia Ma ◽  
Felix Strieth-Kalthoff
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Alkyl Radical ◽  
General Strategy ◽  
Alkyl Radicals ◽  
Bond Forming ◽  
Radical Trapping ◽  
Carbon Carbon Bond ◽  
Radical Generation ◽  
Trapping Agent

<sub>A general strategy to access both aryl and alkyl radicals by photosensitized decarboxylation of the corresponding carboxylic acids esters has been developed. An energy transfer mediated homolysis of unsymmetrical sigma-bonds for a concerted fragmentation/decarboxylation process is involved. As a result, an independent aryl/alkyl radical generation step enables a series of key C-X and C-C bond forming reactions by simply changing the radical trapping agent.</sub>

Enhanced Nitrogen Photo Fixation Performance of Transition Metal-Doped Urchin-Like W18O49 Under Visible-Light Irradiation

NANO ◽  
2019 ◽  
Vol 14 (11) ◽  
pp. 1950143 ◽  
Author(s):  
Jianhua Ge ◽  
Jing Xu ◽  
Yujie Liu ◽  
Long Zhang ◽  
Lan Wang ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
General Strategy ◽  
Bet Specific Surface Area ◽  
Optimum Reaction ◽  
Free Transition ◽  
And Migration ◽  
Metal Doped ◽  
Adsorption Desorption

Nitrogen photo fixation mediated by various photocatalysts has received extensive concerns in recent years. In this work, a general strategy is proposed to enhance nitrogen photo fixation performance with some W[Formula: see text]O[Formula: see text]-based photocatalysts under visible-light irradiation. A series of photocatalysts were successfully synthesized in the presence of some noble-metal-free transition metals (Fe, Co and Ni) to modify the urchin-like W[Formula: see text]O[Formula: see text]. The resulting photocatalysts were systematically characterized using XRD, SEM, EDS, XPS, PL, N2 adsorption–desorption isotherms, and DRS. Structural characterization of the photocatalysts revealed that the crystal morphology features were preserved, optional harvesting properties were enhanced, BET specific surface area was extended, and migration efficiency of the photo-induced charge carriers was significantly improved in the modified-W[Formula: see text]O[Formula: see text] materials. Therefore, a progressed nitrogen photo fixation performance was observed. The maximum production of NH[Formula: see text] was approximately reached to 2752[Formula: see text][Formula: see text]g[Formula: see text][Formula: see text][Formula: see text]g[Formula: see text] catal. under the optimum reaction conditions. Furthermore, a plausible nitrogen photo fixation mechanism in the presence of the synthesized composites is also proposed.

scholarly journals A General Approach for All-visible-light Switching of Diarylethenes through Triplet Sensitization using Semiconducting Nanocrystals

2021 ◽  
Author(s):  
Lili Hou ◽  
Wera Larsson ◽  
Stefan Hecht ◽  
Joakim Andreasson ◽  
Bo Albinsson
Keyword(s):  
Visible Light ◽  
Organic Molecules ◽  
General Strategy ◽  
Triplet Energy ◽  
Excitation Energies ◽  
Photochemical Transformations ◽  
Efficient Route ◽  
Material Sciences ◽  
Triplet Energy Transfer ◽  
Triplet Excitons

Abstract Coupling semiconducting nanocrystals (NCs) with organic molecules provides an efficient route to generate and transfer triplet excitons. These excitons can be used to power photochemical transformations such as photoisomerization reactions using low energy radiation. Thus, it is desirable to develop a general approach that can efficiently be used to control photoswitches using all-visible-light aiming at future applications in life- and material sciences. Here, we demonstrate a simple ‘cocktail’ strategy that can achieve all-visible-light switchable diarylethenes (DAEs) through triplet energy transfer from the hybrid of CdS NCs and phenanthrene-3-carboxylic acid, with high photoisomerization efficiency and improved fatigue resistance. The size-tunable excitation energies of CdS NCs make it possible to precisely match the corresponding energy of the relevant DAE photoswitch. We demonstrate reversible all-visible-light photoisomerization of a series of DAE derivatives both in the liquid and solid state, even in the presence of oxygen. Our general strategy is promising for fabrication of all-visible-light activated optoelectronic devices as well as memories, and should in principle be adaptable to photopharmacology.

Studies of metaphase chromosomes in the scanning transmission x-ray microscope: Image fidelity, radiation damage and specimen preparation

1992 ◽  
Vol 50 (2) ◽  
pp. 1038-1039
Author(s):  
Shawn Williams ◽  
Xiaodong Zhang ◽  
Susan Lamm ◽  
Jack Van’t Hof
Keyword(s):  
Visible Light ◽  
Radiation Damage ◽  
Cross Section ◽  
Imaging Techniques ◽  
Dose Range ◽  
Specimen Preparation ◽  
X Rays ◽  
Metaphase Chromosomes ◽  
X Ray ◽  
Scanning Transmission

The Scanning Transmission X-ray Microscope (STXM) is well suited for investigating metaphase chromosome structure. The absorption cross-section of soft x-rays having energies between the carbon and oxygen K edges (284 - 531 eV) is 6 - 9.5 times greater for organic specimens than for water, which permits one to examine unstained, wet biological specimens with resolution superior to that attainable using visible light. The attenuation length of the x-rays is suitable for imaging micron thick specimens without sectioning. This large difference in cross-section yields good specimen contrast, so that fewer soft x-rays than electrons are required to image wet biological specimens at a given resolution. But most imaging techniques delivering better resolution than visible light produce radiation damage. Soft x-rays are known to be very effective in damaging biological specimens. The STXM is constructed to minimize specimen dose, but it is important to measure the actual damage induced as a function of dose in order to determine the dose range within which radiation damage does not compromise image quality.

Scanning luminescence x-ray microscopy: Progress toward selective staining using microspheres

1994 ◽  
Vol 52 ◽  
pp. 74-75
Author(s):  
C. Jacobsen ◽  
J. Fu ◽  
S. Mayer ◽  
Y. Wang ◽  
S. Williams
Keyword(s):  
Visible Light ◽  
Active Sites ◽  
Light Emission ◽  
Chinese Hamster ◽  
Polystyrene Spheres ◽  
Good Resistance ◽  
X Ray ◽  
Selective Staining ◽  
Visible Light Emission ◽  
Specific Labelling

In scanning luminescence x-ray microscopy (SLXM), a high resolution x-ray probe is used to excite visible light emission (see Figs. 1 and 2). The technique has been developed with a goal of localizing dye-tagged biochemically active sites and structures at 50 nm resolution in thick, hydrated biological specimens. Following our initial efforts, Moronne et al. have begun to develop probes based on biotinylated terbium; we report here our progress towards using microspheres for tagging.Our initial experiments with microspheres were based on commercially-available carboxyl latex spheres which emitted ~ 5 visible light photons per x-ray absorbed, and which showed good resistance to bleaching under x-ray irradiation. Other work (such as that by Guo et al.) has shown that such spheres can be used for a variety of specific labelling applications. Our first efforts have been aimed at labelling ƒ actin in Chinese hamster ovarian (CHO) cells. By using a detergent/fixative protocol to load spheres into cells with permeabilized membranes and preserved morphology, we have succeeded in using commercial dye-loaded, spreptavidin-coated 0.03μm polystyrene spheres linked to biotin phalloidon to label f actin (see Fig. 3).

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