All articles starting with P
28,818 articles
Photoredox flow chemistry
Photoredox flow chemistry conducts photocatalytic reactions, in which a photocatalyst transfers single electrons to generate radical intermediates, in continuous-flow reactors that give uniform light exposure and scale from milligrams to kilograms per day.
Photoredox Minisci reaction
The photoredox Minisci reaction is a visible-light version of the Minisci reaction in which a photocatalyst generates carbon radicals that add to the C–H bonds of heteroarenes.
Photoredox NHC catalysis
Photoredox NHC catalysis is a dual-catalysis strategy in organic synthesis that combines N-heterocyclic carbene organocatalysis with photoredox catalysis, using visible light to drive radical reactions under mild conditions.
Photoredox nickel-catalyzed C–O and C–N cross-coupling
Photoredox nickel-catalyzed C–O and C–N cross-coupling is a metallaphotoredox reaction family combining a nickel catalyst with a light-absorbing photoredox catalyst to form carbon–oxygen and carbon–nitrogen bonds.
Photoredox organocatalysis
Photoredox organocatalysis is a dual-catalysis strategy in organic synthesis that merges a visible-light photoredox catalyst with a chiral organocatalyst, pioneered by Nicewicz and MacMillan's 2008 enantioselective α-alkylation of aldehydes.
Photoredox proton-coupled electron transfer
Photoredox proton-coupled electron transfer is a bond-activation strategy in visible-light catalysis where a photoexcited catalyst and an acid or base remove or deliver an electron and a proton together.
Photoredox trifluoromethylation
Photoredox trifluoromethylation is a visible-light method that attaches trifluoromethyl (CF3) groups to organic molecules through radicals, pioneered by Nagib and MacMillan in Nature in 2011.
Photoredox α-amino C–H functionalization
Photoredox α-amino C–H functionalization is a set of visible-light-driven reactions that turn the C–H bond adjacent to nitrogen in amines into carbon–carbon or carbon–heteroatom bonds.
Photoredox-catalyzed alkene carbofunctionalization
Photoredox-catalyzed alkene carbofunctionalization is a family of organic reactions in which visible-light single-electron-transfer catalysis installs carbon-based groups across an alkene's double bond, widely used in drug and natural product synthesis.
Photoredox-catalyzed alkene difunctionalization
Photoredox-catalyzed alkene difunctionalization is a set of synthetic methods that add two functional groups across an alkene in one operation, using visible-light photocatalysts to generate radical intermediates under mild conditions.
Photoredox-catalyzed arene C–H alkylation via radical cations
Photoredox-catalyzed arene C–H alkylation via radical cations is a metal-free method for attaching alkyl groups to arene C–H bonds, reported by the Nicewicz group at UNC in 2020.
Photoredox-catalyzed carboxylation with CO2
Photoredox-catalyzed carboxylation with CO2 is a family of organic reactions in which a visible-light photocatalyst activates carbon dioxide to form carbon–carbon bonds under mild conditions.
Photoredox-catalyzed decarboxylative C(sp3)–C(sp3) coupling
Photoredox-catalyzed decarboxylative C(sp3)–C(sp3) coupling is a family of organic reactions in which a visible-light-excited photocatalyst converts carboxylic acids into alkyl radicals, forming carbon–carbon bonds under mild conditions without organometallic reagents.
Photoredox-catalyzed dehalogenative functionalization of alkyl halides
Photoredox-catalyzed dehalogenative functionalization of alkyl halides is a family of visible-light reactions that turn alkyl halides into carbon radicals for new bonds, replacing toxic tin reagents.
Photoredox-catalyzed hydrogen isotope exchange
Photoredox-catalyzed hydrogen isotope exchange (photoredox HIE) is a set of light-driven methods for replacing hydrogen with deuterium or tritium in organic molecules, first reported by MacMillan in 2017.
Photoredox-catalyzed trifluoromethylation with CF3SO2Cl
A visible-light photoredox method for installing trifluoromethyl groups onto organic molecules using trifluoromethanesulfonyl chloride (CF3SO2Cl), established for arenes and heteroarenes by David MacMillan's group at Princeton in 2011.
Photoredox-enabled Giese addition of redox-active esters
Photoredox-enabled Giese addition of redox-active esters is a visible-light carbon–carbon bond-forming reaction that turns NHPI esters of carboxylic acids into alkyl radicals adding to electron-poor alkenes.
Photoredox-enabled ring contractions and expansions
Light-driven skeletal edits of cyclic molecules where a visible-light-excited photocatalyst generates radical intermediates that shrink or enlarge rings by one or more atoms, first shaped around 2020.
Photoredox-generated iminyl radical chemistry
Photoredox-generated iminyl radical chemistry is a branch of organic synthesis that uses visible-light photoredox catalysis to generate iminyl radicals from oxime derivatives for C–N and C–C bond formation.
Photoredox-induced 1,2-metalate migration of boronate complexes
Photoredox-induced 1,2-metalate migration of boronate complexes is a family of visible-light-driven reactions, first reported in 2017, in which a radical adds to a boronate complex and a carbon substituent then migrates from boron.
Photoredox-mediated Giese addition
Photoredox-mediated Giese addition is a visible-light-driven form of the Giese reaction: a photocatalyst generates a carbon-centered radical under mild conditions, and it adds to an electron-deficient alkene to form a carbon–carbon bond.
Photoredox/nickel-catalyzed C(sp3)–H arylation
Photoredox/nickel-catalyzed C(sp3)–H arylation is a dual-catalytic organic reaction, first reported in 2014, in which a photocatalyst and nickel convert alkyl C–H bonds into carbon–aryl bonds using aryl halides.
Photoreflectance
Photoreflectance is a contactless modulation spectroscopy technique that measures pump-induced changes in a sample's optical reflectance, used to characterize semiconductor band structure, transition energies, and built-in electric fields at room temperature.
Photoreforming
Photoreforming is a solar-driven photocatalytic process that couples oxidation of organic substrates such as biomass, plastic waste, or wastewater with water reduction, producing hydrogen gas and value-added carbon products instead of oxygen.
Photorefractive effect
The photorefractive effect is a light-induced change in a material's refractive index, produced when redistributed charge builds an internal field via the electro-optic effect, first observed in 1966.
Photorefractive keratectomy
Photorefractive keratectomy (PRK) is a type of refractive surgery that uses an excimer laser to reshape the cornea, without a flap, correcting myopia, hyperopia, and astigmatism.
Photoresist
Photoresist is a light-sensitive film applied to a silicon wafer in photolithography, the process the semiconductor industry uses to define circuit patterns; positive resists become soluble on exposure, negative resists harden.
Photoresistor
A photoresistor, also called a light-dependent resistor (LDR) or photocell, is an electronic component whose resistance falls as light increases, used in street lights and camera exposure meters.
Photorespiration
Photorespiration: light-dependent O2 uptake and CO2 release in oxygenic photosynthesis, also called the C2 cycle. Rubisco oxygenation produces toxic 2-phosphoglycolate, recycled at high ATP and NADPH cost; target of crop bypass engineering.
Photoresponsive hydrogels
Photoresponsive hydrogels are crosslinked, water-rich polymer networks that change stiffness, structure, or drug release when illuminated, used in drug delivery, tissue engineering, and soft robotics.