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Search for "photocatalysts" in Full Text gives 106 result(s) in Beilstein Journal of Organic Chemistry.

Visible-light-induced radical cascade cyclization: a catalyst-free synthetic approach to trifluoromethylated heterocycles

  • Chuan Yang,
  • Wei Shi,
  • Jian Tian,
  • Lin Guo,
  • Yating Zhao and
  • Wujiong Xia

Beilstein J. Org. Chem. 2024, 20, 118–124, doi:10.3762/bjoc.20.12

Graphical Abstract
  • radicals. This method allows the efficient synthesis of various indole derivatives without the need of photocatalysts or transition-metal catalysts. Mechanism experiments indicate that the process involves a radical chain process initiated by the homolysis of Umemoto's reagent. This straightforward method
  • usually occur under mild conditions, they typically require expensive metal-based photocatalysts or structurally complex organic dyes [18]. Therefore, the development of a photoinduced cascade reaction without the need of additional catalysts or additives remains highly desirable [19]. The introduction of
  • to furnish trifluoromethylated dihyropyrido[1,2-a]indolones under mild conditions, without the need of photocatalysts or transition metals [28]. Results and Discussion We initialized our study by employing Ru(bpy)3Cl2·6H2O and Umemoto’s reagent to generate trifluoromethyl radicals via a photo
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Published 19 Jan 2024

Optimizing reaction conditions for the light-driven hydrogen evolution in a loop photoreactor

  • Pengcheng Li,
  • Daniel Kowalczyk,
  • Johannes Liessem,
  • Mohamed M. Elnagar,
  • Dariusz Mitoraj,
  • Radim Beranek and
  • Dirk Ziegenbalg

Beilstein J. Org. Chem. 2024, 20, 74–91, doi:10.3762/bjoc.20.9

Graphical Abstract
  • in a proper way, solar energy can be converted to hydrogen fuels. Hydrogen as an energy carrier has zero carbon emission and a high energy density [11][12]. While significant efforts are directed towards developing effective photocatalysts for solar water splitting [13][14][15][16], a crucial
  • the contrary, expanding photocatalytic systems, particularly those employing powdered photocatalysts, to a larger scale is notably more straightforward [17][18]. However, complications arise when attempting to scale up reactors solely based on geometric similarity, as alterations in mixing and
  • , identifying photocatalysts capable of efficient performance across broad sunlight wavelength ranges proves to be a complex endeavor [26][27][28]. Therefore, artificial light sources are typically applied for lab testing of photocatalytic reactions. Compared to conventional light sources, light-emitting diodes
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Published 16 Jan 2024

Beyond n-dopants for organic semiconductors: use of bibenzo[d]imidazoles in UV-promoted dehalogenation reactions of organic halides

  • Kan Tang,
  • Megan R. Brown,
  • Chad Risko,
  • Melissa K. Gish,
  • Garry Rumbles,
  • Phuc H. Pham,
  • Oana R. Luca,
  • Stephen Barlow and
  • Seth R. Marder

Beilstein J. Org. Chem. 2023, 19, 1912–1922, doi:10.3762/bjoc.19.142

Graphical Abstract
  • of alkyl halides, RX, by CoCp2 (Cp = η5-cyclopentadienyl; E = −1.3 V vs FeCp2+/0), gives CoCp2+ and X−, but the organic radicals R• react with another molecule of CoCp2 to afford CoCp(η4-C5H5R) [7]. In some cases, issues of reductant air sensitivity can be circumvented by the use of photocatalysts in
  • and photocatalysts used, and (c) schematic for the present approach, along with structures of 1,1',3,3'-tetramethyl-2,2',3,3'-tetrahydro-2,2'-bibenzo[d]imidazoles, (Y-DMBI)2, and the corresponding monomer cations, specifically the first reported in the literature and those used in this work. (a) A
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Published 14 Dec 2023

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

  • Tinglan Liu,
  • Yu Zhou,
  • Junhong Tang and
  • Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

Graphical Abstract
  • esters 8, 9 without the requirements of phosphine or other photocatalysts (Scheme 5). Through the use of density functional theory (DFT) calculations, they elucidated the mechanism behind this process. It was revealed that the formation of a photoactive EDA complex, which subsequently generated alkyl
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Published 22 Nov 2023

Quinoxaline derivatives as attractive electron-transporting materials

  • Zeeshan Abid,
  • Liaqat Ali,
  • Sughra Gulzar,
  • Faiza Wahad,
  • Raja Shahid Ashraf and
  • Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

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  • compound with the donor polymer PM6 to create BHJ nanoparticles and employed it in the hydrogen evolution reaction. This approach substantially reduced trap density, increasing the hydrogen evolution rate by 2–3 times compared to conventional inorganic/organic hybrid photocatalysts [30]. Computational
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Published 09 Nov 2023

Visible-light-induced nickel-catalyzed α-hydroxytrifluoroethylation of alkyl carboxylic acids: Access to trifluoromethyl alkyl acyloins

  • Feng Chen,
  • Xiu-Hua Xu,
  • Zeng-Hao Chen,
  • Yue Chen and
  • Feng-Ling Qing

Beilstein J. Org. Chem. 2023, 19, 1372–1378, doi:10.3762/bjoc.19.98

Graphical Abstract
  • complex between Hantzsch ester and N-trifluoroethoxyphthalimide was subsequently engaged in a nickel-catalyzed coupling reaction with in situ-activated alkyl carboxylic acids. This convenient protocol does not require photocatalysts and metal reductants, providing a straightforward and efficient access to
  • photocatalysts, providing a direct and robust access to trifluoromethyl aliphatic acyloins. Results and Discussion Initially, we commenced our exploration by choosing 4-phenylbutyric acid (1a) as the model substrate to react with N-trifluoroethoxyphthalimide (2, Table 1). On basis of the previously reported
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Published 11 Sep 2023

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp3)–H to construct C–C bonds

  • Hui Yu and
  • Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

Graphical Abstract
  • , noble metals have been extensively studied as photocatalysts for CDC reactions [116][117][118][119][120][121] and these methods fill the gap of traditional thermocatalytic CDC reactions. In 2017, Ryu et al. developed tetrabutylammonium decatungstate (TBADT, (n-Bu4N)4[W10O32] as a photocatalyst to
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Published 06 Sep 2023
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  • , inorganic Z-schemes have used cobalt complexes and polyoxometalates to shuttle electrons between water oxidation and carbon dioxide reduction photocatalysts [2][4]. However, the photocatalysts of these systems are usually first developed separately with sacrificial electron donors. Other methods for
  • bringing together the 2 halves of artificial photosynthesis include photoelectrochemical cells and artificial leaves, single molecule/particle photocatalysts, photovoltaic-powered electrochemical cells, and biophotoelectrochemical cells [8][9]. Some of these systems, like natural photosynthesis, are
  • sulfides, or a separate deprotonation event can also result in similar behavior. Gimeno et al. highlighted this when they designed novel benzimidazole (BIH) donors for the photoreduction with [Cu(dipp)2]2+ photocatalysts [29][30]. They contrasted their work to a previous study by Cunningham and McMillin
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Published 08 Aug 2023

Photoredox catalysis harvesting multiple photon or electrochemical energies

  • Mattia Lepori,
  • Simon Schmid and
  • Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

Graphical Abstract
  • PEC, a main theme of this Review. Protocols for sensitization-initiated electron transfer (SenI-ET) relying on a dual catalytic system of transition-metal based photocatalysts and pyrenes to generate highly reductive species are also excluded as such reported transformations are now equally achievable
  • limited to electron-poor arenes like diazonium/iodonium salts or aryl iodides with electron-withdrawing substituents as aryl radical precursors, due to the limited accessible reducing power of photocatalysts that relied on a monophotonic excitation event. However, the vast majority of inexpensive
  • chlorides including 4-bromoanisole and 4-chloroanisole (2e), 1-bromo-2,4- dimethoxybenzene (2f) and 4-ethylchlorobenzene (2h) occurred in good to excellent yields (58–99%) (Figure 10B). Based on their exciting success with isophthalonitrile derived compounds as electron-primed photocatalysts in e-PRC (vide
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Published 28 Jul 2023

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

  • Austin Pounder,
  • Eric Neufeld,
  • Peter Myler and
  • William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

Graphical Abstract
  •  7) instead of the more commonly, and expensive, metal-based photocatalysts. While broadly successful, tertiary radicals failed to deliver any desired product. Of note, the reaction was amenable to a broad scope of derivatized heterobicyclic alkenes with mono- and disubstituted bridgeheads having
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Published 24 Apr 2023

NaI/PPh3-catalyzed visible-light-mediated decarboxylative radical cascade cyclization of N-arylacrylamides for the efficient synthesis of quaternary oxindoles

  • Dan Liu,
  • Yue Zhao and
  • Frederic W. Patureau

Beilstein J. Org. Chem. 2023, 19, 57–65, doi:10.3762/bjoc.19.5

Graphical Abstract
  • disclosed a visible light-mediated radical tandem cyclization of N-arylacrylamides with N-(acyloxy)phthalimides to access 3,3-dialkylated oxindoles in the presence of [Ru(bpy)3Cl2]·6H2O [46]. However, these seminal methods remain limited by the need of noble-metal-based photocatalysts, excess additives and
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Published 16 Jan 2023

Mechanochemical bottom-up synthesis of phosphorus-linked, heptazine-based carbon nitrides using sodium phosphide

  • Blaine G. Fiss,
  • Georgia Douglas,
  • Michael Ferguson,
  • Jorge Becerra,
  • Jesus Valdez,
  • Trong-On Do,
  • Tomislav Friščić and
  • Audrey Moores

Beilstein J. Org. Chem. 2022, 18, 1203–1209, doi:10.3762/bjoc.18.125

Graphical Abstract
  • minimize the bandgap of these metal-free photocatalysts, as well as improve their overall stability. Traditional routes to incorporate phosphorus have relied on high-temperature [7] or microwave [8] syntheses, and often proceed through the introduction of a phosphorus atom within the heptazine ring, which
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Published 12 Sep 2022

Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor

  • Wei-Hsin Hsu,
  • Susanne Reischauer,
  • Peter H. Seeberger,
  • Bartholomäus Pieber and
  • Dario Cambié

Beilstein J. Org. Chem. 2022, 18, 1123–1130, doi:10.3762/bjoc.18.115

Graphical Abstract
  • visible-light photocatalysts that enable new reaction pathways that were previously difficult or impossible to realize [2]. Technical advancements, such as the rise of light-emitting diodes (LEDs) and new reactor technologies were similarly important incentives to popularize light-mediated organic
  • sufficiently (photo-)stable, a higher turnover number can be achieved [16]. Issues related to the low surface-to-volume ratio that prevents efficient irradiation of heterogeneous photocatalysts in packed beds can be addressed by adding, for example, glass beads [21]. These considerations have justified the
  • development of several strategies to immobilize transition-metal photocatalysts [22]. In the case of flow-metallaphotoredox catalysis packed-bed reactors were not applied to date. This is likely because these reactions are mainly carried out using homogeneous catalysis. Several studies have shown that the
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Published 29 Aug 2022

Synthesis of α-(perfluoroalkylsulfonyl)propiophenones: a new set of reagents for the light-mediated perfluoroalkylation of aromatics

  • Durbis J. Castillo-Pazos,
  • Juan D. Lasso and
  • Chao-Jun Li

Beilstein J. Org. Chem. 2022, 18, 788–795, doi:10.3762/bjoc.18.79

Graphical Abstract
  • halogenation reactions or oxidation. For these reasons, it would be ideal to develop an efficient methodology that allows for the generation of perfluoroalkyl radicals in a mild, redox- and pH-neutral manner, without the assistance of external photocatalysts, heavy metal catalysts, or further additives. Thus
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Published 04 Jul 2022

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

  • Prodip Howlader and
  • Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62

Graphical Abstract
  • + 26), respectively, were successfully employed as visible-light photocatalysts for a cross-coupling cyclization of N,N-dimethylaniline (27) and N-alkyl/aryl maleimides 28 (Figure 6). Notably, the systems showed much higher catalytic activity compared to similar reactions with the dye or cages alone
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Published 27 May 2022

Menadione: a platform and a target to valuable compounds synthesis

  • Acácio S. de Souza,
  • Ruan Carlos B. Ribeiro,
  • Dora C. S. Costa,
  • Fernanda P. Pauli,
  • David R. Pinho,
  • Matheus G. de Moraes,
  • Fernando de C. da Silva,
  • Luana da S. M. Forezi and
  • Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

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Published 11 Apr 2022

Synthesis of piperidine and pyrrolidine derivatives by electroreductive cyclization of imine with terminal dihaloalkanes in a flow microreactor

  • Yuki Naito,
  • Naoki Shida and
  • Mahito Atobe

Beilstein J. Org. Chem. 2022, 18, 350–359, doi:10.3762/bjoc.18.39

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  • which realizes for the construction of medium-sized saturated nitrogen heterocycles [21]. Although the process enables the rapid construction of saturated nitrogen heterocycles from acyclic precursors, it requires homogeneous precious transition metal complexes as photocatalysts. On the other hand
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Published 29 Mar 2022

DABCO-promoted photocatalytic C–H functionalization of aldehydes

  • Bruno Maia da Silva Santos,
  • Mariana dos Santos Dupim,
  • Cauê Paula de Souza,
  • Thiago Messias Cardozo and
  • Fernanda Gadini Finelli

Beilstein J. Org. Chem. 2021, 17, 2959–2967, doi:10.3762/bjoc.17.205

Graphical Abstract
  • , increased accessibility and with structural features that may lead to different reactivities and/or selectivities that are still to be explored. The different electrochemical behaviour of DABCO may also lead to alternative photocatalysts for its activation, such as organic dyes that may not be suitable for
  • catalysts and photocatalysts [9][10][11][12][21][22][23]. Previous reports of DABCO as hydrogen abstractor in HAT reactions and this work. Free energy profile for the HAT step reactions between isovaleraldehyde with (top) DABCO and (bottom) quinuclidine radical cations. The red lines are for the gas phase
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Published 21 Dec 2021

Visible-light-mediated copper photocatalysis for organic syntheses

  • Yajing Zhang,
  • Qian Wang,
  • Zongsheng Yan,
  • Donglai Ma and
  • Yuguang Zheng

Beilstein J. Org. Chem. 2021, 17, 2520–2542, doi:10.3762/bjoc.17.169

Graphical Abstract
  • renewable energy and green chemistry for many years. Ruthenium and iridium, which can be used as photoredox catalysts, are expensive and scarce in nature. Thus, the further development of catalysts based on these transition metals is discouraged. Alternative photocatalysts based on copper complexes are
  • organic dyes and metal complexes have been investigated [10][11][12]. Photoredox catalysts have been initially applied to organic reactions, but they are now used for complicated organic processes [13]. As photocatalysts, organic dyes have the advantages of having a low price and not containing metals
  • electrons from donors are relatively scarce in the literature. Thus, the RQC pathway rarely occurs for CuI-photocatalyzed reactions. Yet, CuI complexes have the potential to replace ruthenium or iridium-based photocatalysts in reductive photoredox reactions due to their strong reduction ability [22][29
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Published 12 Oct 2021

Exfoliated black phosphorous-mediated CuAAC chemistry for organic and macromolecular synthesis under white LED and near-IR irradiation

  • Azra Kocaarslan,
  • Zafer Eroglu,
  • Önder Metin and
  • Yusuf Yagci

Beilstein J. Org. Chem. 2021, 17, 2477–2487, doi:10.3762/bjoc.17.164

Graphical Abstract
  • , we present a novel synthetic methodology for the photoinduced CuAAC reaction utilizing exfoliated two-dimensional (2D) few-layer black phosphorus nanosheets (BPNs) as photocatalysts under white LED and near-IR (NIR) light irradiation. Upon irradiation, BPNs generated excited electrons and holes on
  • polymer modification by adding spatial and temporal control [12][13]. In recent years, heterogeneous photocatalysts have been performed in many photosynthetic reactions since they provide a more reasonable and easy way to synthesize the targeted products compared to the classical homogenous photocatalysts
  • photocatalysts have been successfully applied in both small- and large-scale synthesis such as organic reactions [16][17], free radical polymerization (FRP) [18][19][20], controlled radical polymerization (CRP) [21][22], CuAAC chemistry [23][24][25], and thiol–ene chemistry [26][27]. However, most of the
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Published 23 Sep 2021

Photoredox catalysis in nickel-catalyzed C–H functionalization

  • Lusina Mantry,
  • Rajaram Maayuri,
  • Vikash Kumar and
  • Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

Graphical Abstract
  • developments in the field of photoredox nickel-catalyzed C‒H functionalization reactions with a range of applications until summer 2021. Keywords: C–H activation; functionalization; nickel; photocatalysts; photoredox; visible light; Introduction During the last decades, transition-metal-catalyzed
  • catalysis under blue light irradiation (Scheme 45) [128]. Among the tested several commercially available photocatalysts, Ir[dF(CF3)ppy]2(dtbbpy)PF6 was found to provide the desired products in good yields. Aldehyde C–H functionalization Inspired by their earlier contributions on HAT-metallaphotoredox
  • opportunities for late-stage diversification of complex molecules. Despite the significant advances, the photoredox-mediated nickel-catalyzed C‒H functionalization is still in its infancy. Thus far, expensive iridium-based complexes are the most common photocatalysts and are essential to achieve satisfactory
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Published 31 Aug 2021

Cerium-photocatalyzed aerobic oxidation of benzylic alcohols to aldehydes and ketones

  • Girish Suresh Yedase,
  • Sumit Kumar,
  • Jessica Stahl,
  • Burkhard König and
  • Veera Reddy Yatham

Beilstein J. Org. Chem. 2021, 17, 1727–1732, doi:10.3762/bjoc.17.121

Graphical Abstract
  • thermal conditions. Significant advances were made for the oxidation of benzylic alcohols by using metal-based photocatalysts [38][39][40][41][42][43][44][45][46] and metal-free photocatalysis [47][48][49][50][51][52][53] in combination with various oxidants, such as TBHP and DDQ [54][55]. However, the
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Published 23 Jul 2021

Heterogeneous photocatalytic cyanomethylarylation of alkenes with acetonitrile: synthesis of diverse nitrogenous heterocyclic compounds

  • Guanglong Pan,
  • Qian Yang,
  • Wentao Wang,
  • Yurong Tang and
  • Yunfei Cai

Beilstein J. Org. Chem. 2021, 17, 1171–1180, doi:10.3762/bjoc.17.89

Graphical Abstract
  • photocatalysts are used; and the scope remains limited to activated alkenes. Therefore, it is still highly desirable to develop a general, efficient, and practical protocol for the cyanomethylarylation of unactivated alkenes from readily available radical initiators under mild and environmentally benign
  • ]. In the last few years, carbon nitride-based heterogeneous photocatalysts have also been utilized for several other radical-initiated synthetic transformations [44][45][46][47][48][49][50][51][52][53][54][55][56]. However, to the best of our knowledge, the application of a CN-based photocatalyst for
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Published 17 May 2021

Insight into functionalized-macrocycles-guided supramolecular photocatalysis

  • Minzan Zuo,
  • Krishnasamy Velmurugan,
  • Kaiya Wang,
  • Xueqi Tian and
  • Xiao-Yu Hu

Beilstein J. Org. Chem. 2021, 17, 139–155, doi:10.3762/bjoc.17.15

Graphical Abstract
  • photocatalytic reaction with a rate acceleration facilitated by supramolecular host–guest interactions and hybrid materials are typically assisted by noncovalent forces, including Coulomb and van der Waals forces, hydrogen bonding, and π–π interactions. For potential supramolecular photocatalysts, they should
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Published 18 Jan 2021

Dawn of a new era in industrial photochemistry: the scale-up of micro- and mesostructured photoreactors

  • Emine Kayahan,
  • Mathias Jacobs,
  • Leen Braeken,
  • Leen C.J. Thomassen,
  • Simon Kuhn,
  • Tom van Gerven and
  • M. Enis Leblebici

Beilstein J. Org. Chem. 2020, 16, 2484–2504, doi:10.3762/bjoc.16.202

Graphical Abstract
  • performance dropped 17% after 6 h of operation and remained stable for the next 19.5 h [51]. Similarly, glass beads coated with photocatalysts were proved to increase the photoreaction rate twice in a luminescent solar concentrator (LSC) photomicroreactor with capillary channels [50]. Azam et al. studied
  • combination of an oscillatory flow with the static mixers of the HANU reactor (Figure 5c) enabled a stable suspension of the photocatalysts without clogging of the reactor channels [58]. Corning flow reactors are designed to provide good mixing for multiphase reactions with periodic heart-shaped static mixers
  • (a pharmaceutical micropollutant) from urban wastewater. The effect of a catalyst-coated surface and the illumination mechanism were studied. When a larger surface area was coated with the photocatalysts, the photocatalyst reactivity was increased [61]. Marinho et al. compared the performance of the
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Published 08 Oct 2020
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