10 research outputs found
A highly reducing metal-free photoredox catalyst: design and application in radical dehalogenations
Here we report the use of 10-phenylphenothiazine (PTH) as an inexpensive, highly reducing metal-free photocatalyst for the reduction of carbon-halogen bonds via the trapping of carbon-centered radical intermediates with a mild hydrogen atom donor. Dehalogenations were carried out on various substrates with excellent yields at room temperature in the presence of air
Chemoselective Radical Dehalogenation and C-C Bond Formation on Aryl Halide Substrates Using Organic Photoredox Catalysts.
Tunable visible and near infrared photoswitches
The article of record as published may be found at http://dx.doi.org/10.1021/jacs.6b07434A class of tunable visible and near-infrared donorâacceptor Stenhouse adduct (DASA) photoswitches were efficiently synthesized in two to four steps from commercially available starting materials with
minimal purification. Using either Meldrumâs or barbituric acid âacceptorsâ in combination with aniline-based âdonorsâ, an absorption range spanning from 450 to 750 nm is obtained. Additionally, photoisomerization results in complete decoloration for all adducts, yielding fully transparent,
colorless solutions and films. Detailed investigations using density functional theory, nuclear magnetic resonance, and visible absorption spectroscopies provide valuable insight into the unique structureâproperty relationships for this novel class of photoswitches. As a final demonstration, selective photochromism is accomplished in a variety of solvents and polymer matrices, a significant advantage for applications of this new generation of DASAs.National Science Foundation (MRSEC program DMR 1121053)California NanoSystems Institute (CNSI) Challenge Grant Progra
Controlled drug release to cancer cells from modular one-photon visible light-responsive micellar system
We present a one-photon visible light-responsive micellar system for efficient, on-demand delivery of small molecules. Release is mediated by a novel class of photochromic material - donor-acceptor Stenhouse adducts (DASAs). We demonstrate controlled delivery of small molecules such as the chemotherapeutic agent (paclitaxel) to human breast cancer cells triggered by micellar switching with low intensity, visible light
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Controlled drug release to cancer cells from modular one-photon visible light-responsive micellar system.
We present a one-photon visible light-responsive micellar system for efficient, on-demand delivery of small molecules. Release is mediated by a novel class of photochromic material - donor-acceptor Stenhouse adducts (DASAs). We demonstrate controlled delivery of small molecules such as the chemotherapeutic agent (paclitaxel) to human breast cancer cells triggered by micellar switching with low intensity, visible light
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A highly reducing metal-free photoredox catalyst: design and application in radical dehalogenations.
Here we report the use of 10-phenylphenothiazine (PTH) as an inexpensive, highly reducing metal-free photocatalyst for the reduction of carbon-halogen bonds via the trapping of carbon-centered radical intermediates with a mild hydrogen atom donor. Dehalogenations were carried out on various substrates with excellent yields at room temperature in the presence of air
Recommended from our members
Tunable Visible and Near Infrared Photoswitches.
A class of tunable visible and near-infrared donor-acceptor Stenhouse adduct (DASA) photoswitches were efficiently synthesized in two to four steps from commercially available starting materials with minimal purification. Using either Meldrum's or barbituric acid "acceptors" in combination with aniline-based "donors", an absorption range spanning from 450 to 750 nm is obtained. Additionally, photoisomerization results in complete decoloration for all adducts, yielding fully transparent, colorless solutions and films. Detailed investigations using density functional theory, nuclear magnetic resonance, and visible absorption spectroscopies provide valuable insight into the unique structure-property relationships for this novel class of photoswitches. As a final demonstration, selective photochromism is accomplished in a variety of solvents and polymer matrices, a significant advantage for applications of this new generation of DASAs
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Chemoselective Radical Dehalogenation and CâC Bond Formation on Aryl Halide Substrates Using Organic Photoredox Catalysts
Despite
the number of methods available for dehalogenation and
carbonâcarbon bond formation using aryl halides, strategies
that provide chemoselectivity for systems bearing multiple carbonâhalogen
bonds are still needed. Herein, we report the ability to tune the
reduction potential of metal-free phenothiazine-based photoredox catalysts
and demonstrate the application of these catalysts for chemoselective
carbonâhalogen bond activation to achieve CâC cross-coupling
reactions as well as reductive dehalogenations. This procedure works
both for conjugated polyhalides as well as unconjugated substrates.
We further illustrate the usefulness of this protocol by intramolecular
cyclization of a pyrrole substrate, an advanced building block for
a family of natural products known to exhibit biological activity