scholarly journals Green-Light Induced Cycloadditions

2021 ◽  
Author(s):  
Philipp W. Kamm ◽  
James P Blinco ◽  
Andreas Unterreiner ◽  
Christopher Barner-Kowollik
Keyword(s):  
Green Light ◽  
Light Irradiation ◽  
Nitrile Imine

We introduce a red-shifted tetrazole that is able to undergo efficient nitrile imine-mediated tetrazole-ene cycloaddition (NITEC) under blue and green light irradiation. We provide a detailed wavelength-dependent reactivity map, and...

scholarly journals Switching Between Enantiomers by Combining Chromoselective Photocatalysis and Biocatalysis

2021 ◽  
Author(s):  
Luca Schmermund ◽  
Susanne Reischauer ◽  
Sarah Bierbaumer ◽  
Christoph Winkler ◽  
Alba Diaz-Rodriguez ◽  
...  
Keyword(s):  
Photocatalytic Oxidation ◽  
Green Light ◽  
Light Irradiation ◽  
Thermal Processes ◽  
Rhodococcus Ruber ◽  
Oxidation Potentials ◽  
Enzymatic Cascades ◽  
Electron Holes ◽  
External Stimuli ◽  
Generate Electron

<a></a><a></a><a></a><a></a><a></a><a>Controlling the selectivity of a chemical reaction with external stimuli is common in thermal processes, but rare in visible-light photocatalysis. Here we show that the redox potential of a carbon nitride photocatalyst (CN-OA-m) can be tuned by changing the irradiation wavelength to generate electron holes with different oxidation potentials. This tuning was the key to realizing photo-chemo-enzymatic cascades that give either the (<i>S</i>)- or the (<i>R</i>)-enantiomer of phenylethanol. In combination with an unspecific peroxygenase from <i>Agrocybe aegerita,</i> green light irradiation of CN-OA-m led to the enantioselective hydroxylation of ethylbenzene to (<i>R</i>)-1-phenylethanol (99% <i>ee</i>). In contrast, blue light irradiation triggered the photocatalytic oxidation of ethylbenzene to acetophenone, which in turn was enantioselectively reduced with an alcohol dehydrogenase from <i>Rhodococcus ruber </i>to form<i> </i>(<i>S</i>)-1-phenylethanol (93% <i>ee</i>).</a><a></a>

scholarly journals Green light irradiation during sex differentiation induces female-to-male sex reversal in the medaka Oryzias latipes

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Oki Hayasaka ◽  
Yutaka Takeuchi ◽  
Kazuhiro Shiozaki ◽  
Kazuhiko Anraku ◽  
Tomonari Kotani
Keyword(s):  
Sex Differentiation ◽  
Green Light ◽  
Oryzias Latipes ◽  
Sex Reversal ◽  
Light Irradiation ◽  
Male Sex

scholarly journals Polymeric Self-Assemblies Based on tetra-ortho-Substituted Azobenzene as Visible Light Responsive Nanocarriers

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2060
Author(s):  
Alejandro Roche ◽  
Luis Oriol ◽  
Rosa M. Tejedor ◽  
Milagros Piñol
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Diblock Copolymers ◽  
Uv Light ◽  
Morphological Changes ◽  
Nile Red ◽  
Green Light ◽  
Light Irradiation ◽  
Transmission Electron ◽  
Amphiphilic Diblock Copolymers

Most of reported polymeric light-responsive nanocarriers make use of UV light to trigger morphological changes and the subsequent release of encapsulated cargoes. Moving from UV- to visible-responsive units is interesting for the potential biomedical applications of these materials. Herein we report the synthesis by ring opening polymerization (ROP) of a series of amphiphilic diblock copolymers, into which either UV or visible responsive azobenzenes have been introduced via copper(I) catalyzed azide-alkyne cycloaddition (CuAAC). These copolymers are able to self-assemble into spherical micelles or vesicles when dispersed in water. The study of the response of the self-assemblies upon UV (365 nm) or visible (530 or 625 nm) light irradiation has been studied by Transmission Electron Microscopy (TEM), Cryogenic Transmission Electron Microscopy (Cryo-TEM), and Dynamic Light Scattering (DLS) studies. Encapsulation of Nile Red, in micelles and vesicles, and Rhodamine B, in vesicles, and its light-stimulated release has been studied by fluorescence spectroscopy and confocal microscopy. Appreciable morphological changes have been induced with green light, and the subsequent release of encapsulated cargoes upon green light irradiation has been confirmed.

PHOTOCATALYTIC ACTIVITY OF NITROGEN AND FLUORINE CO-DOPED TITANIUM DIOXIDE PREPARED USING OF VARIOUS PH SOLUTIONS

2010 ◽  
Vol 24 (15n16) ◽  
pp. 3242-3247 ◽  
Author(s):  
MASAHIRO KATOH ◽  
AKIHIRO IMAYAMA ◽  
NARISUKE MORI ◽  
TOSHIHIDE HORIKAWA ◽  
TAHEI TOMIDA
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Uv Light ◽  
Anatase Phase ◽  
Wave Length ◽  
Green Light ◽  
Light Irradiation ◽  
Mixed Solution ◽  
Co Doped

Introducing different atoms into TiO 2 crystal lattice is a famous method to improve photocatalytic activity of TiO 2 under visible-light irradiation. In this paper, Nitrogen ( N ) and fluorine ( F ) co -doped TiO 2 powders were prepared by mixing TiCl 3 solutions with ammonium fluoride ( NH 4 F ). In preparation, we used NH 3- H 2 O solution for adjustment of pH values (pH 2, 7, and 9) of mixed solution. X-ray diffraction (XRD) indicated N , F - TiO 2 powders prepared at pH7 and pH9 contained only anatase phase, but the powders prepared at pH2 contained both anatase and rutile phase. The result of XRD also indicated N , F - TiO 2 powders prepared at pH7 had the smallest crystallite size. We measured photocatalytic activity of prepared N , F - TiO 2 powders by the decomposition of methylene blue. N , F - TiO 2 powder prepared at pH7 and pH9 showed same high photocatalytic activity under ultraviolet light irradiation (peak wave length = 352 nm). Furthermore, under green light LED irradiation (wave length = 525 nm), a sample prepared at pH7 decomposed methylene blue more quickly than any other samples. As the result, N , F - TiO 2 prepared at pH7 had the best catalytic activity under both UV-light and visible light in the all of N , F - TiO 2 prepared and reference TiO 2 photocatalyst (ST-01 produced by Ishihara Co. Ltd).

scholarly journals Photoactivable Ruthenium-Based Coordination Polymer Nanoparticles for Light-Induced Chemotherapy

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3089
Author(s):  
Junda Zhang ◽  
Vadde Ramu ◽  
Xue-Quan Zhou ◽  
Carolina Frias ◽  
Daniel Ruiz-Molina ◽  
...  
Keyword(s):  
Coordination Polymer ◽  
High Performance ◽  
Green Light ◽  
Fold Increase ◽  
Polymer Nanoparticles ◽  
Light Irradiation ◽  
Bridging Ligands ◽  
Monomeric Complex ◽  
First Time

Green light photoactive Ru-based coordination polymer nanoparticles (CPNs), with chemical formula [[Ru(biqbpy)]1.5(bis)](PF6)3 (biqbpy = 6,6′-bis[N-(isoquinolyl)-1-amino]-2,2′-bipyridine; bis = bis(imidazol-1-yl)-hexane), were obtained through polymerization of the trans-[Ru(biqbpy)(dmso)Cl]Cl complex (Complex 1) and bis bridging ligands. The as-synthesized CPNs (50 ± 12 nm diameter) showed high colloidal and chemical stability in physiological solutions. The axial bis(imidazole) ligands coordinated to the ruthenium center were photosubstituted by water upon light irradiation in aqueous medium to generate the aqueous substituted and active ruthenium complexes. The UV-Vis spectral variations observed for the suspension upon irradiation corroborated the photoactivation of the CPNs, while High Performance Liquid Chromatography (HPLC) of irradiated particles in physiological media allowed for the first time precisely quantifying the amount of photoreleased complex from the polymeric material. In vitro studies with A431 and A549 cancer cell lines revealed an 11-fold increased uptake for the nanoparticles compared to the monomeric complex [Ru(biqbpy)(N-methylimidazole)2](PF6)2 (Complex 2). After irradiation (520 nm, 39.3 J/cm2), the CPNs yielded up to a two-fold increase in cytotoxicity compared to the same CPNs kept in the dark, indicating a selective effect by light irradiation. Meanwhile, the absence of 1O2 production from both nanostructured and monomeric prodrugs concluded that light-induced cell death is not caused by a photodynamic effect but rather by photoactivated chemotherapy.

scholarly journals TLD1433 Photosensitizer Inhibits Conjunctival Melanoma Cells in Zebrafish Ectopic and Orthotopic Tumour Models

Cancers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 587 ◽  
Author(s):  
Quanchi Chen ◽  
Vadde Ramu ◽  
Yasmin Aydar ◽  
Arwin Groenewoud ◽  
Xue-Quan Zhou ◽  
...  
Keyword(s):  
Therapeutic Potential ◽  
Green Light ◽  
Light Irradiation ◽  
Conjunctival Melanoma ◽  
Orthotopic Model ◽  
Administration Regimen ◽  
Anti Cancer ◽  
Clinical Models ◽  
Ocular Cancer ◽  
Apoptosis And Necrosis

The ruthenium-based photosensitizer (PS) TLD1433 has completed a phase I clinical trial for photodynamic therapy (PDT) treatment of bladder cancer. Here, we investigated a possible repurposing of this drug for treatment of conjunctival melanoma (CM). CM is a rare but often deadly ocular cancer. The efficacy of TLD1433 was tested on several cell lines from CM (CRMM1, CRMM2 and CM2005), uveal melanoma (OMM1, OMM2.5, MEL270), epidermoid carcinoma (A431) and cutaneous melanoma (A375). Using 15 min green light irradiation (21 mW/cm2, 19 J.cm−2, 520 nm), the highest phototherapeutic index (PI) was reached in CM cells, with cell death occurring via apoptosis and necrosis. The therapeutic potential of TLD1433 was hence further validated in zebrafish ectopic and newly-developed orthotopic CM models. Fluorescent CRMM1 and CRMM2 cells were injected into the circulation of zebrafish (ectopic model) or behind the eye (orthotopic model) and 24 h later, the engrafted embryos were treated with the maximally-tolerated dose of TLD1433. The drug was administrated in three ways, either by (i) incubating the fish in drug-containing water (WA), or (ii) injecting the drug intravenously into the fish (IV), or (iii) injecting the drug retro-orbitally (RO) into the fish. Optimally, four consecutive PDT treatments were performed on engrafted embryos using 60 min drug-to-light intervals and 90 min green light irradiation (21 mW/cm2, 114 J.cm−2, 520 nm). This PDT protocol was not toxic to the fish. In the ectopic tumour model, both systemic administration by IV injection and RO injection of TLD1433 significantly inhibited growth of engrafted CRMM1 and CRMM2 cells. However, in the orthotopic model, tumour growth was only attenuated by localized RO injection of TLD1433. These data unequivocally prove that the zebrafish provides a fast vertebrate cancer model that can be used to test the administration regimen, host toxicity and anti-cancer efficacy of PDT drugs against CM. Based on our results, we suggest repurposing of TLD1433 for treatment of incurable CM and further testing in alternative pre-clinical models.

scholarly journals PET-RAFT Polymerization Catalyzed by Small Organic Molecule under Green Light Irradiation

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 892 ◽  
Author(s):  
Huazhen Tao ◽  
Lei Xia ◽  
Guang Chen ◽  
Tianyou Zeng ◽  
Xuan Nie ◽  
...  
Keyword(s):  
Noble Metals ◽  
Organic Molecules ◽  
Raft Polymerization ◽  
Green Light ◽  
Light Irradiation ◽  
Chain Extension ◽  
Reversible Addition ◽  
Low Toxicity ◽  
Broad Interest ◽  
Easy Operation

Photocatalyzed polymerization using organic molecules as catalysts has attracted broad interest because of its easy operation in ambient environments and low toxicity compared with metallic catalysts. In this work, we reported that 4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole (DTBT) can act as an efficient photoredox catalyst for photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization under green light irradiation. Well-defined (co)polymers can be obtained using this technique without any additional additives like noble metals and electron donors or acceptors. The living characteristics of polymerization were verified by kinetic study and the narrow dispersity (Đ) of the produced polymer. Excellent chain-end fidelity was demonstrated through chain extension as well. In addition, this technique showed great potential for various RAFT agents and monomers including acrylates and acrylamides.

Custom-Made Pyrene Photocatalyst-Promoted Desulfonylation of Arylethenyl Sulfones Using Green-Light-Emitting Diodes

Synthesis ◽  
2021 ◽  
Author(s):  
Akihiro Orita ◽  
Hikaru Watanabe ◽  
Kazuki Nakajima ◽  
Kento Ekuni ◽  
Ryota Edagawa ◽  
...  
Keyword(s):  
Visible Light ◽  
Column Chromatography ◽  
Visible Light Irradiation ◽  
Light Emitting Diodes ◽  
Green Light ◽  
Light Irradiation ◽  
Sonogashira Coupling ◽  
Light Emitting ◽  
Custom Made

AbstractThe Sonogashira coupling of 1,3,6,8-tetrabromopyrene with 4-[(–)-β-citronellyloxy]phenylethyne was employed to synthesize 1,3,6,8-tetra[4-(citronellyloxy)phenylethynyl]pyrene. The pyrene derivative catalyzed the reductive desulfonylation of ethenyl sulfones via visible-light irradiation (514 nm green light-emitting diodes) in the presence of i-Pr2NEt. The β-citronellyloxy groups provided the sufficient solubility to the highly π-expanded pyrene catalyst, and their polar oxygen functionalities enabled the easy separation of the catalyst from the products via column chromatography.

EFFECTS OF GREEN LIGHT IRRADIATION ON INDUCTION OF DISEASE RESISTANCE IN PLANTS

2011 ◽  
pp. 251-254 ◽  
Author(s):  
R. Kudo ◽  
Y. Ishida ◽  
K. Yamamoto
Keyword(s):  
Disease Resistance ◽  
Green Light ◽  
Light Irradiation
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