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| Open AccessTriplet-driven chemical reactivity of β-carotene and its biological implications
The endoperoxides of β-carotene play a key role in signaling of photooxidative stress in plant cells and are regarded as the products of chemical deactivation of singlet oxygen. The authors show that these compounds are instead formed in a reaction between oxygen and β-carotene in their triplet states, revealing the importance of the triplet states in the photoprotection of photosynthetic apparatus.
- Mateusz Zbyradowski
- , Mariusz Duda
- & Leszek Fiedor
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Article
| Open AccessPhotoinduced ynamide structural reshuffling and functionalization
Although ynamides have emerged as a versatile class of compounds for organic synthesis, the radical chemistry of ynamides usually proceeds with the expected connectivity largely intact. Here the authors show a methodology by which the C(sp)–N bond undergoes scission, alkyne migration and functionalization under blue LED light in the absence of metals or additives.
- Mohana Reddy Mutra
- & Jeh‐Jeng Wang
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Article
| Open AccessTwo-photon-absorbing ruthenium complexes enable near infrared light-driven photocatalysis
The field of homogeneous metal- and photocatalysis typically uses one-photon-absorbing photosensitizers, which are highly functional, but require higher-energy light. Here the authors report a group of ruthenium polypyridyl complexes possessing two-photon-absorption capabilities, active with irradiation with lower-energy (740 nm) light.
- Guanqun Han
- , Guodong Li
- & Yujie Sun
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Article
| Open AccessThe initial charge separation step in oxygenic photosynthesis
The photosystem II reaction center (PSII-RC) is a model system to understand the initial steps of photosynthesis, but its excited state dynamics is difficult to disentangle with most spectroscopic methods. Here the authors perform a two-dimensional electronic-vibrational spectroscopic study of PSII-RC, providing detailed insight into such dynamics and into the mechanism of charge separation.
- Yusuke Yoneda
- , Eric A. Arsenault
- & Graham R. Fleming
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Article
| Open AccessAn osmium-peroxo complex for photoactive therapy of hypoxic tumors
Photodynamic therapy has been a promising technique for the treatment of tumours. In this manuscript, the authors report on the photoactivation of the osmium peroxo complex and its potential use for chemotherapy and photodynamic therapy under blue light irradiation against tumours in their hypoxic environment.
- Nong Lu
- , Zhihong Deng
- & Pingyu Zhang
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Article
| Open AccessAn unexpected strategy to alleviate hypoxia limitation of photodynamic therapy by biotinylation of photosensitizers
Type I photodynamic therapy (PDT) sensitizers show good hypoxia tolerance but only few strategies are available for the design of purely organic Type I photosensitizers (PS). Here, the authors use biotinylation as design strategy to obtain PS-Biotin sensitizers with high efficiency for the generation of superoxide anion radicals and singlet oxygen.
- Jing An
- , Shanliang Tang
- & Wen-Heng Zheng
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Article
| Open AccessControlling forward and backward rotary molecular motion on demand
Being able to control motion at the molecular level is vital for many future developments in the molecular sciences. Here, the authors report the controlled forward and backward rotation of a molecular motor guided by external stimuli.
- L. Pfeifer
- , S. Crespi
- & B. L. Feringa
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Article
| Open AccessLight-driven transition-metal-free direct decarbonylation of unstrained diaryl ketones via a dual C–C bond cleavage
The cleavage and formation of carbon−carbon bonds is an important strategy for structural modifications in organic syntheses. Herein, the authors present a photoinduced method to construct biaryl compounds through dual inert C−C bond cleavage.
- Dawei Cao
- , Mohamad Ataya
- & Chao-Jun Li
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Article
| Open AccessSynthesis of fluorescent organic nano-dots and their application as efficient color conversion layers
Compared to inorganic nanoparticles, organic nanoparticles aren’t as well understood. Here the authors explore the use of surfactants to prepare organic semiconductor nanoparticles with outstanding photophysical properties.
- Yeasin Khan
- , Soonjae Hwang
- & Jang Hyuk Kwon
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Article
| Open AccessPhoto-induced trifunctionalization of bromostyrenes via remote radical migration reactions of tetracoordinate boron species
Tetracoordinate boron species are common radical precursors in organic synthesis, but the boron species are discarded as by-products. Herein the authors report a strategy to incorporate both the alkyl moiety and boron species into the eventual products, yielding organoboron compounds.
- Chaokun Li
- , Shangteng Liao
- & Qiuling Song
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Article
| Open AccessEnantioselective functionalization at the C4 position of pyridinium salts through NHC catalysis
A catalytic method for the enantioselective and C4-selective functionalization of pyridine derivatives is yet to be developed. Here the authors report an efficient method for the asymmetric β-pyridylations of enals that involve N-heterocyclic carbene (NHC) catalysis with excellent control over enantioselectivity and pyridyl C4-selectivity.
- Hangyeol Choi
- , Gangadhar Rao Mathi
- & Sungwoo Hong
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Article
| Open AccessStereoselective intermolecular radical cascade reactions of tryptophans or ɤ-alkenyl-α-amino acids with acrylamides via photoredox catalysis
Photocatalytic radical cascade reactions enable the facile construction of diverse cyclic compounds, though they rely on templated precursors. In this paper, the authors report on stereoselective intermolecular radical cascade reaction between tryptophan or ɤ-alkenyl substituted amino acids and acrylamides to synthesise multi-substituted trans-fused hexahydrocarbazoles or 1,3,5-trisubstituted cyclohexanes.
- Jiang-Tao Li
- , Jian-Nan Luo
- & Chun-Xiang Zhuo
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Article
| Open AccessBinary dopant segregation enables hematite-based heterostructures for highly efficient solar H2O2 synthesis
Photoelectrochemical H2O2 production offers a renewable means for chemical synthesis, yet water oxidation to H2O2 remains a challenge. Here, authors prepare heterostructured, metal-doped hematite mesocrystals that show a high selectivity for photoelectrochemical H2O2 alongside H2 production.
- Zhujun Zhang
- , Takashi Tsuchimochi
- & Takashi Tachikawa
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Article
| Open AccessExtra kinetic dimensions for label discrimination
Label discrimination is challenging in fluorescence microscopy due to broad spectra and narrow lifetime distribution. Here, the authors introduce extra kinetic dimensions by illuminating reversibly photoswitchable fluorophores with different intensities, and discriminate 20 spectrally similar fluorophores.
- Raja Chouket
- , Agnès Pellissier-Tanon
- & Ludovic Jullien
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Article
| Open AccessExtracting quantitative dielectric properties from pump-probe spectroscopy
Photoinduced changes in transmission, reflection and scattering prevent conventional pump-probe spectroscopy to unambiguously assign the origin of spectral signatures. Ashoka et al. have developed an optical modelling technique to extract quantitative and unambiguous changes in the dielectric function from standard pump-probe measurements.
- Arjun Ashoka
- , Ronnie R. Tamming
- & Akshay Rao
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Article
| Open AccessPhotoinduced bond oscillations in ironpentacarbonyl give delayed synchronous bursts of carbonmonoxide release
The photodissociation of transition metal carbonyls is involved in catalysis and synthetic processes. Here the authors, using semi-classical excited state molecular dynamics, observe details of the early stage dynamics in the photodissociation of Fe(CO)5, including synchronous bursts of CO at periodic intervals of 90 femtoseconds.
- Ambar Banerjee
- , Michael R. Coates
- & Michael Odelius
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Article
| Open AccessOverall photosynthesis of H2O2 by an inorganic semiconductor
An inorganic and robust photocatalytic system based on Mo-doped faceted BiVO4 particles exhibits a solar-to-chemical conversion efficiency of 0.29% for H2O2 generation, a new record among inorganic systems.
- Tian Liu
- , Zhenhua Pan
- & Kazunari Domen
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Article
| Open AccessVisible light-driven efficient palladium catalyst turnover in oxidative transformations within confined frameworks
Pd(II) catalyst turnover by reoxidation of a low valent Pd species is the key step for a Pd(II) catalyzed oxidation reaction. Here, the authors report a new strategy to address Pd reoxidation by fabricating spatially proximate photocatalyst and Pd(II) catalyst into metal-organic framework.
- Jiawei Li
- , Liuqing He
- & Huanfeng Jiang
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Article
| Open AccessInterface engineering of Ta3N5 thin film photoanode for highly efficient photoelectrochemical water splitting
Solar-to-fuel energy conversion requires well-designed materials properties to ensure favorable charge carrier movement. Here, authors employ interface engineering of Ta3N5 thin film to enhance bulk carrier separation and interface carrier injection to improve the water-splitting efficiency.
- Jie Fu
- , Zeyu Fan
- & Yanbo Li
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Article
| Open AccessLiquid-microjet photoelectron spectroscopy of the green fluorescent protein chromophore
The electronic structures of photoactive proteins underlie many natural photoinduced processes. The authors, using UV liquid-microjet photoelectron spectroscopy and quantum chemistry calculations, determine electron detachment energies of the green fluorescent protein chromophore in aqueous solution, approaching conditions of the protein environment.
- Omri Tau
- , Alice Henley
- & Helen H. Fielding
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Article
| Open AccessAmino acid gas phase circular dichroism and implications for the origin of biomolecular asymmetry
Chiroptical properties of amino acids are challenging to investigate in the gas phase due to the low vapor pressure of these molecules. Here the authors succeed in measuring circular dichroism active transitions and anisotropies in the ultraviolet range for several gas-phase amino acids, shedding light on the interactions between molecules and circularly polarized light that lead to chiral symmetry breaking.
- Cornelia Meinert
- , Adrien D. Garcia
- & Uwe J. Meierhenrich
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Article
| Open AccessUnraveling of cocatalysts photodeposited selectively on facets of BiVO4 to boost solar water splitting
Artificial photosynthesis offers an integrated means to convert light to fuel, but efficiencies are often low. Here, authors report a Z-scheme system utilizing Ir and FeCoOx co-catalysts to enhance charge separation on BiVO4 facets that achieves high quantum efficiencies for overall water splitting.
- Yu Qi
- , Jiangwei Zhang
- & Fuxiang Zhang
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Article
| Open AccessSelective photoinduced charge separation in perylenediimide-pillar[5]arene rotaxanes
The development of complex molecular machinery requires a detailed appreciation of the factors that control energy pathways through the nanoscale scaffold. Here, the authors demonstrate that hetero-rotaxanes can be employed to create assemblies of different redox and photo-active components that enable selective tuning of energy transfer pathways.
- Nicholas Pearce
- , Katherine E. A. Reynolds
- & Neil R. Champness
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Article
| Open AccessPhotocatalytic defluoroalkylation and hydrodefluorination of trifluoromethyls using o-phosphinophenolate
Photoredox catalysis can strongly reduce and cleave unactivated chemical bonds via photoinduced electron transfer. Here the authors use o-phosphinophenolate for photocatalytic C–F activation of a wide range of trifluoromethyl groups in trifluoroacetamides, trifluoroacetates, and trifluoromethyl(hetero)arenes to deliver corresponding difluoromethyl radicals.
- Can Liu
- , Ni Shen
- & Rui Shang
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Article
| Open AccessA combined experimental and theoretical study on the reactivity of nitrenes and nitrene radical anions
Gaining in-depth understanding of photochemical processes is key for developing more sustainable and efficient chemical transformations. Here the authors show that under visible light photochemical conditions, iminoiodinanes undergo formation of triplet nitrenes or nitrene radical anions, depending on the use of a photosensitizer; These reagents are studied in amination reactions with olefins.
- Yujing Guo
- , Chao Pei
- & Rene M. Koenigs
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Article
| Open AccessDynamics and mechanism of dimer dissociation of photoreceptor UVR8
UVR8 is a plant photoreceptor that dissociates into monomers after sensing UV. Here, via ultrafast spectroscopy and computational calculations, the authors describe the dynamics of charge separation and charge neutralization in UVR8 and describe how these unzip interactions at the dimer interface.
- Xiankun Li
- , Zheyun Liu
- & Dongping Zhong
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Article
| Open AccessPhotocontrolled multiple-state photochromic benzo[b]phosphole thieno[3,2-b]phosphole-containing alkynylgold(I) complex via selective light irradiation
Photoresponsive compounds have potential applications in various fields, including the development of smart materials and switches. Here the authors report a gold(I) complex that undergoes multiple photoinduced color changes upon excitation of light at specific wavelengths, offering an enhanced storage capacity towards optical memory devices.
- Nathan Man-Wai Wu
- , Maggie Ng
- & Vivian Wing-Wah Yam
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Article
| Open AccessTracking excited state decay mechanisms of pyrimidine nucleosides in real time
The photophysical mechanism by which nucleosides dissipate energy after UV light irradiation is still under debate. Here the authors, using ultrafast time resolved optical spectroscopies and quantum chemical computations, resolve the early steps of such mechanism in uridine and 5-methyluridine in aqueous solution.
- Rocío Borrego-Varillas
- , Artur Nenov
- & Giulio Cerullo
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Article
| Open AccessDivergent functionalization of aldehydes photocatalyzed by neutral eosin Y with sulfone reagents
Acyl radicals represent a reactive species that allow for aldehyde subunits to be nucleophilic instead of their typical electrophilic behavior; however, these species are difficult to access in mild conditions. Here the authors show a method to generate acyl radicals using only an organic photocatalyst and light, and these species are shown as competent nucleophiles in a variety of couplings.
- Jianming Yan
- , Haidi Tang
- & Jie Wu
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Article
| Open AccessNitrogen-incorporation activates NiFeOx catalysts for efficiently boosting oxygen evolution activity and stability of BiVO4 photoanodes
While solar-to-fuel conversion offers a renewable energy production strategy, photoelectrochemical water splitting requires further optimization. Here, authors examined nitrogen-doped NiFeOx catalysts to improve the oxygen evolution activity and stability of BiVO4 photoanodes.
- Beibei Zhang
- , Shiqiang Yu
- & Yingpu Bi
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Article
| Open AccessVisible-light-mediated catalyst-free synthesis of unnatural α-amino acids and peptide macrocycles
To address the shortcomings in the application of bioactive peptides as drugs, incorporation of unnatural amino acids (UAAs) has been used. Here, the authors report an ionic compound-promoted C-N cleavage of alkyl pyridinium to generate alkyl radicals upon excitation by visible light, and apply it for deaminative hydroalkylation of alkenes to synthesise diverse β-alkyl substituted UAAs.
- Mengran Wang
- , Chao Wang
- & Zhaoqing Xu
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Article
| Open AccessNanoscale π-conjugated ladders
Increasing the rigidity of a macromolecule while maintaining solubility is challenging. Here, the authors demonstrate covalent connection of two rigid-rod polymer chains with stiff connectors, leading to rigid ladder structures with well-defined conjugated rails.
- Stefanie A. Meißner
- , Theresa Eder
- & Sigurd Höger
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Article
| Open AccessImmobilized covalent triazine frameworks films as effective photocatalysts for hydrogen evolution reaction
While covalent triazine frameworks are promising photocatalytic materials, it is challenging to prepare large-scale thin films. Here, authors report an interfacial polymerization method to prepare photocatalytic covalent triazine framework thin films with lateral sizes up to 250 cm2.
- Xunliang Hu
- , Zhen Zhan
- & Bien Tan
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Article
| Open AccessPhoto-induced catalytic halopyridylation of alkenes
The Mizoroki–Heck reaction and its reductive analogue are staples of organic synthesis, but the ensuing products often lack a chemical handle for further transformation. Here the authors present a method to add a heterocycle and transformable halide across a double bond via iridium photocatalysis.
- Shi-Yu Guo
- , Fan Yang
- & Qing-An Chen
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Article
| Open AccessMicrocavity-like exciton-polaritons can be the primary photoexcitation in bare organic semiconductors
Exciton-polaritons are typically formed in organic systems when the molecules are confined between metallic or dielectric mirrors. Here, the authors reveal that interactions between excitons and moderately confined photonic states within the bare organic film can also lead to polariton formation, making them the primary photoexcitation.
- Raj Pandya
- , Richard Y. S. Chen
- & Akshay Rao
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Article
| Open AccessPhoto-induced copper-catalyzed sequential 1,n-HAT enabling the formation of cyclobutanols
Cyclobutanols are difficult structures to access given their inherent ring strain. Here, the authors present a method to form substituted cyclobutanols from a photocatalytic cascade reaction, proceeding via a 1,5- or 1,6-hydrogen atom transfer and subsequent ring closure.
- Zhusong Cao
- , Jianye Li
- & Guozhu Zhang
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Article
| Open AccessFaradaic junction and isoenergetic charge transfer mechanism on semiconductor/semiconductor interfaces
Energy band alignment theory is used to understand interface charge transfer in semiconductor/semiconductor junctions but many abnormal results cannot be well explained. Here, the authors demonstrate a Faradaic junction theory with isoenergetic charge transfer at semiconductor/semiconductor interfaces to explain these abnormal results.
- Mingzhi Chen
- , Hongzheng Dong
- & Zhigang Zou
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Article
| Open AccessHot exciplexes in U-shaped TADF molecules with emission from locally excited states
Molecular designs improving the performance of thermally activated delayed fluorescence (TADF) emitters are greatly desired for optoelectronic applications. The authors propose a molecular geometry with donor and acceptor moieties facing each other separated by an anthracene bridge, giving rise to hot exciplex states producing color pure and fast TADF emission.
- A. Lennart Schleper
- , Kenichi Goushi
- & Alexander J. C. Kuehne
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Article
| Open AccessBottom-up modular synthesis of well-defined oligo(arylfuran)s
Oligofurans have attracted great attention because of their strong fluorescence, charge delocalization, and increased solubility. Here the authors show a bottom-up modular construction of chemically and structurally well-defined oligo(arylfuran)s by de novo synthesis of α,β′-bifuran monomers and late-stage bromination, stannylation and subsequent coupling reaction.
- Yang Chen
- , Pingchuan Shen
- & Shifa Zhu
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Article
| Open AccessAnti-Markovnikov hydro(amino)alkylation of vinylarenes via photoredox catalysis
Many useful chemical scaffolds include carbon or nitrogen substitutions at two or three atoms away from benzene. Here, the authors show a unified hydroalkylation and hydroaminoalkylation protocol to access these structures via a regioselective photocatalytic addition to simple styrenes.
- Zhao Wu
- , Samuel N. Gockel
- & Kami L. Hull
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Article
| Open AccessRelief of excited-state antiaromaticity enables the smallest red emitter
Commonly, large π-conjugated systems facilitate low-energy electronic transitions. Here, the authors demonstrate that the relief of excited-state antiaromaticity of the benzene core leads to large Stokes shifts, and allows the construction of emitters covering the entire visible spectrum without the need of extending π-conjugation.
- Heechan Kim
- , Woojin Park
- & Dongwhan Lee
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Article
| Open AccessSelective deoxygenative alkylation of alcohols via photocatalytic domino radical fragmentations
The generation of alkyl radicals through deoxygenation of abundant alcohols via photoredox catalysis is of interest. In this study, the authors report a one-pot strategy for visible-light-promoted photoredox coupling of alcohols with electron-deficient alkenes, assisted by carbon disulfide and triphenylphosphine.
- Hong-Mei Guo
- & Xuesong Wu
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Article
| Open AccessEfficient access to aliphatic esters by photocatalyzed alkoxycarbonylation of alkenes with alkyloxalyl chlorides
Aliphatic esters are essential constituents of biologically active compounds but their preparation from readily available olefins remains challenging. Here the authors show a strategy to access aliphatic esters from olefins through a unique photocatalyzed alkoxycarbonylation reaction.
- Jian-Qiang Chen
- , Xiaodong Tu
- & Jie Wu
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Article
| Open AccessX-ray transient absorption reveals the 1Au (nπ*) state of pyrazine in electronic relaxation
Radiationless relaxation is ubiquitous in natural processes and often involves excited states that are difficult to observe. Here the authors, combining X-ray transient absorption spectroscopy and computations, provide insight into the photoinduced dynamics in pyrazine and the involvement of an optically dark 1Au(nπ*) state.
- Valeriu Scutelnic
- , Shota Tsuru
- & Stephen R. Leone
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Article
| Open AccessSuperior photo-carrier diffusion dynamics in organic-inorganic hybrid perovskites revealed by spatiotemporal conductivity imaging
Spatiotemporal dynamic of charge carriers is commonly studied with optical or photoconductivity measurements, yet these techniques come with their own limitations. To circumvent these limits, the authors probe the free-carrier diffusion dynamics of microsecond lifetimes via laser-illuminated microwave impedance microscopy.
- Xuejian Ma
- , Fei Zhang
- & Keji Lai
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Article
| Open AccessAnion-exchange-mediated internal electric field for boosting photogenerated carrier separation and utilization
Research on the bulk internal electric field (IEF) regulation is significant for designing high-efficiency photocatalysts. Here, the authors report distinctive bismuth oxyhydroxide nanorods photocatalyst and increase the bulk IEF intensity by halogen ions exchange.
- Tong Han
- , Xing Cao
- & Yadong Li
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Article
| Open AccessSite-specific Umpolung amidation of carboxylic acids via triplet synergistic catalysis
Catalytic amide bond-forming methods is important because they could potentially address the existing limitations of classical methods using superstoichiometric activating reagents. Here the authors show an Umpolung amidation reaction of carboxylic acids with nitroarenes and nitroalkanes enabled by FeI2, P(V)/P(III) and photoredox catalysis that avoids the production of byproducts.
- Yunyun Ning
- , Shuaishuai Wang
- & Jin Xie
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Article
| Open AccessGeneration of non-stabilized alkyl radicals from thianthrenium salts for C–B and C–C bond formation
The generation of non-stabilized alkyl radicals from sulfonium salts has been a challenge for several decades. Here, the authors show the treatment of S-(alkyl) thianthrenium salts, which can generate non-stabilized alkyl radicals as key intermediates that enable controlled and selective reactions under mild photoredox conditions.
- Cheng Chen
- , Zheng-Jun Wang
- & Zhuangzhi Shi
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Article
| Open AccessBoosting photoelectrochemical efficiency by near-infrared-active lattice-matched morphological heterojunctions
The solar conversion efficiencies of photoelectrochemical catalysis are hindered by the light harvesting range. Here, the authors use near-infrared-active photoanodes that feature lattice-matched morphological hetero-nanostructures to realize efficient photoelectrochemical hydrogen production.
- Guo-Qiang Liu
- , Yuan Yang
- & Edward H. Sargent