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Articoli di riviste sul tema "Organic electron donors (OEDs)":
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Cha, Judy J. "Intercalation and Functionalization in 2D Materials". ECS Meeting Abstracts MA2023-01, n. 13 (28 agosto 2023): 1306. http://dx.doi.org/10.1149/ma2023-01131306mtgabs.
Abstract (sommario):
The large surface areas and interlayer gaps of 2D materials enable surface functionalization and intercalation as effective post-synthesis design knobs to tune the properties of 2D materials using ions, atoms, and organic molecules. For complete engineering control, detailed understanding of the interactions between the 2D materials and the molecules adsorbed on 2D materials surface or between the 2D materials and the intercalants is necessary. I will first discuss surface functionalization to tune the electrical properties of 2D materials. We developed an experimental approach to quantitatively measure the doping powers of organic electron donors (OEDs) to monolayer MoS2. Using novel and previously studied OEDs, we demonstrate experimentally that the measured doping power is a sensitive function of molecule’s reduction potential, size, surface coverage, and orientation to 2D materials [1, 2]. I will then discuss electrochemical intercalation into 2D materials to induce novel phases that were previously undetected and to study heterointerface effects on the intercalation induced phase transition [3, 4]. We discover new structural phases in Td-WTe2 and T’-MoTe2 with lithium intercalation and these new phases are semiconducting even though the initial WTe2 and MoTe2 are semimetallic and lithium ions donate electrons to the host materials. In the lithium intercalation-induced phase transition from the 2H to 1T’ phase of MoS2, we show that the nucleation of the 1T’ phase proceeds via heterogeneous nucleation where the nature of heterointerface dictates the thermodynamics of the phase transition. For these studies, multi-modal, in-situ probes were necessary to track the changes in the structure-property relation of the layered materials as a function of intercalation. [1] Advanced Electronic Materials 7, 2000873 (2021). [2] Nano Letters 22, p.4501 (2022). [3] ACS Applied Materials & Interfaces 13, p.10603-10611 (2021). [4] Advanced Materials 34, 2200861 (2022).
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Murphy, John A. "ChemInform Abstract: Organic Electron Donors". ChemInform 43, n. 37 (16 agosto 2012): no. http://dx.doi.org/10.1002/chin.201237244.
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Broggi, Julie, Marion Rollet, Jean-Louis Clément, Gabriel Canard, Thierry Terme, Didier Gigmes e Patrice Vanelle. "Polymerization Initiated by Organic Electron Donors". Angewandte Chemie International Edition 55, n. 20 (8 aprile 2016): 5994–99. http://dx.doi.org/10.1002/anie.201600327.
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Broggi, Julie, Marion Rollet, Jean-Louis Clément, Gabriel Canard, Thierry Terme, Didier Gigmes e Patrice Vanelle. "Polymerization Initiated by Organic Electron Donors". Angewandte Chemie 128, n. 20 (8 aprile 2016): 6098–103. http://dx.doi.org/10.1002/ange.201600327.
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Broggi, Julie, Thierry Terme e Patrice Vanelle. "Organic Electron Donors as Powerful Single-Electron Reducing Agents in Organic Synthesis". Angewandte Chemie International Edition 53, n. 2 (24 novembre 2013): 384–413. http://dx.doi.org/10.1002/anie.201209060.
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Zhou, Shengze, Hardeep Farwaha e John A. Murphy. "The Development of Organic Super Electron Donors". CHIMIA International Journal for Chemistry 66, n. 6 (27 giugno 2012): 418–24. http://dx.doi.org/10.2533/chimia.2012.418.
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Rohrbach, Simon, Rushabh S. Shah, Tell Tuttle e John A. Murphy. "Neutral Organic Super Electron Donors Made Catalytic". Angewandte Chemie International Edition 58, n. 33 (12 agosto 2019): 11454–58. http://dx.doi.org/10.1002/anie.201905814.
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Lowe, Grace A. "Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors". Beilstein Journal of Organic Chemistry 19 (8 agosto 2023): 1198–215. http://dx.doi.org/10.3762/bjoc.19.88.
Abstract (sommario):
This review surveys advances in the literature that impact organic sacrificial electron donor recycling in artificial photosynthesis. Systems for photocatalytic carbon dioxide reduction are optimized using sacrificial electron donors. One strategy for coupling carbon dioxide reduction and water oxidation to achieve artificial photosynthesis is to use a redox mediator, or recyclable electron donor. This review highlights photo- and electrochemical methods for recycling amines and NADH analogues that can be used as electron donors in artificial photosynthesis. Important properties of sacrificial donors and recycling strategies are also discussed. Compounds from other fields, such as redox flow batteries and decoupled water splitting research, are introduced as alternative recyclable sacrificial electron donors and their oxidation potentials are compared to the redox potentials of some model photosensitizers. The aim of this review is to act as a reference for researchers developing photocatalytic systems with sacrificial electron donors, and for researchers interested in designing new redox mediator and recyclable electron donor species.
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Murphy, John A. "Discovery and Development of Organic Super-Electron-Donors". Journal of Organic Chemistry 79, n. 9 (25 marzo 2014): 3731–46. http://dx.doi.org/10.1021/jo500071u.
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Rohrbach, Simon, Rushabh S. Shah, Tell Tuttle e John A. Murphy. "Corrigendum: Neutral Organic Super Electron Donors Made Catalytic". Angewandte Chemie International Edition 58, n. 43 (21 ottobre 2019): 15183. http://dx.doi.org/10.1002/anie.201910425.
Tesi sul tema "Organic electron donors (OEDs)":
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Zhao, Yuxi. "Synthèse de donneurs d’électrons organiques : application en synthèse organique et chimie des polymères". Electronic Thesis or Diss., Aix-Marseille, 2021. http://www.theses.fr/2021AIXM0156.
Abstract (sommario):
Les donneurs d'électrons organiques (DEO), aux potentiels redox exceptionnellement négatifs, ont montré un intérêt particulier en synthèse organique du fait de leurs fortes propriétés réductrices. Ils sont capables de transférer spontanément un ou deux électrons à des substrats organiques, formant ainsi des intermédiaires radicalaires ou anioniques. Néanmoins, la diversité structurale des DEO est limitée et leur champ d'application assez restreint.Dans cette thèse, nous avons tout d'abord développé de nouvelles bibliothèques de DEO afin d'identifier de nouvelles familles de réducteurs organiques, d'élargir la gamme de potentiels redox et d'accéder à de nouvelles réactivités. Des modulations structurales appropriées sur sept catégories de sels d'iminium ont donné accès à de puissants DEO avec diverses capacités réductrices. Cette étude a également permis de rationaliser les facteurs régissant le transfert d’un ou deux électrons en fonction de la structure du DEO et des conditions réactionnelles. Une enquête mécanistique plus approfondie a confirmé les structures des espèces donneuses d'électrons formellement actives. Enfin, les DEO se sont également avérés être de remarquables systèmes redox organiques pour l’amorçage de réactions de polymérisation radicalaire et anionique. Alors que la propagation anionique est initiée par réduction directe du monomère, la simple addition d'un oxydant compétitif, avec un potentiel de réduction plus élevé, permet de passer à un processus de propagation radicalaire. Ces stratégies de polymérisation ont montré une excellente applicabilité pour la préparation d'une large gamme de (co-)polymères à haute valeur ajoutéeOrganic electron donors (OEDs) with exceptionally negative redox potentials have attracted considerable attention in organic synthesis as powerful reducers. They enable the spontaneous transfer of one or two electrons to organic substrates, to form radical or anionic intermediates. Nevertheless, the structural diversity of OEDs is limited and their application scope quite narrow. In this thesis, we first developed novel libraries of OEDs in order to identify new families of organic reducers, broaden the range of redox potentials and access new reducing reactivities. Appropriate structural modulations on seven categories of iminium salts gave access to powerful OED with various reducing abilities. It also allowed to rationalize the factors governing single- or double-electron transfers according to the OED structures and the reaction conditions. A more thorough mechanistic investigation was conducted to formally confirm the active electron donor species at work.Finally, OEDs also appeared to be remarkable organic redox initiating systems for both free radical and anionic polymerization reactions. While the anionic propagation was promoted by direct reduction of the monomer, simple addition of a competing oxidant with a higher reduction potential allowed to switch to a clean free radical propagation process. Scope investigation exhibited excellent applicability of these self-initiating polymerization strategies, which enabled the preparation of a large array of (co-)polymers with high added values
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Schonebeck, Franziska. "Super electron donors powerful reductions performed by neutral organic molecules". Thesis, University of Strathclyde, 2007. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21732.
Abstract (sommario):
This project aims to explore the ability of organic molecules to transfer electrons and is based on the recent development within the Murphy group of a novel organic molecule, called Super-S.E.T. reagent 1, that allows the reduction of unactivated aryl and alkyl iodides. My study investigates the scope of donor 1 as a reducing agent and extends the study to a more powerful donor 2. Chapter One provides an introduction to the world of electron transfer. After giving a theoretical background, synthetic applications of electron transfer are highlighted, in particular using metal chemistry, electrochemical and photochemical methods. This chapter also discusses the use of sulfones and sulfonamides as challenging substrates for electron transfer. Finally the field of neutral organic electron-donors, which form the basis of my studies, is introduced. Chapters Two to Seven then summarise my work. Chapter Two and the second part of Chapter Six highlight my adventures in investigating the chemistry of donor 1. Until now, donor 1 is known to reduce efficiently only specific aryl and alkyl iodides. This report (i) highlights the scope and limitations of donor 1 in the reduction of different aryl iodide substrates and of aryl halides other than iodides and (ii) discusses the application of donor 1 in the selective reduction of an ortho- over an analogous para-aryl iodide in substrate 3 and (iii) recounts the successful isolation of the first adduct of the donor, i.e. 4. Chapter Three to Six deal with the exploration of the power of Super-S.E.T. reagent 2. This donor was successfully applied as a powerful reducing agent in the reductive cleavages of a number of activated sulfones and sulfonamides, giving the reduced counterparts in excellent yields. Further, strong evidence for the first example of a Julia olefination using a neutral organic electron donor has been given. It was also shown that the reagent has remarkable reducing power, being the first neutral organic reagent to generate highly reactive aryl anion intermediates in the reduction of aryl 3 bromides and iodides. Ester substrates 5,6 and 7 were synthesised and investigated as mechanistic probes in that context. The chemistry of donor 2 with aliphatic halides was investigated, leading to the formation of aldehydes in DMF or DMA. It was found that the proportion of aldehyde can be increased with more equivalents of donor 2, ultimately leading to the aldehyde being the exclusive product. Using non-polar solvents, such as diethyl ether, donor 2 was transformed into a powerful reducing agent for alkyl bromides, reacting at room temperature and showing radical chemistry. Selective reduction of an alkyl over aryl bromide was achieved also. Intriguing reactivity was observed with anthracene esters, giving the dihydroester as one of the major products, if a carbene is added, and dihydroanthracene if not. After a summary of results in Chapter Seven, Chapter Eight presents the experimental procedures and analytical data for the compounds discussed in Chapters Two to Six.
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Cumine, Florimond. "Studies on organic electron donors and their applications in chemistry". Thesis, University of Strathclyde, 2017. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=29432.
Abstract (sommario):
Electron transfer reactions using organic donors have been and are still successfully applied in the Murphy group to perform reductions usually requiring heavy metals. This thesis focuses on several organic electron donors used to: (i) promote the cross-coupling reaction between aryl halides and benzene, which was also studied with computational experiments, (ii) cleave carbon-oxygen bonds and (iii) reduce nitrobenzenes and azobenzenes. In addition, computational analysis of controversial literature proposals for a radical/electron transfer mechanism for ring-forming reactions of alkoxide allenes and amide allenes is reported and supports an anionic rather than a radical process. Chapter Two highlights the ability of diketopiperazines 1-4 to promote the cross-coupling reactions of aryl halides 5-16 with benzene in the presence of potassium tert-butoxide 17 to form biaryls 18-24 via electron transfer [graphic of electron transfer process]. It also investigates the different outcomes of the reaction when a diketopiperazine is used or not, providing evidence for formation of a benzyne intermediate which can lead to both the coupling product with benzene (when aryl iodides are used) and to tert-butoxybenzenes. Chapter Three explores electron transfer reactions that lead to alkyl aryl ether deprotection. It highlights that tert-butyllithium 25 performs this deprotection and shows the series of reactions that led to evidence of an anionic addition of phenyllithium 26 to benzene and also of tert-butyllithium 25 to benzene [graphic of base-induced process and additions to Benzene with oxidative termination]. Chapter Four focuses on a 4-DMAP-derived organic electron donor 32, commonly referred to as 'DMAP donor', that reduces nitrobenzene 34 and azobenzene 36, amongst others, under UV activation or thermal conditions, via successive single electron transfers. This chapter also discusses the unlikely possibility of an electron transfer from the DMAP donor 32 to the 1,2-diphenylhydrazine dianion 38 leading to the formation of aniline dianion 39. More rational mechanistic considerations involving the reduced diphenylhydrazine and dication 33 will be described to explain the formation of aniline 35 [graphic of DMAP electron donor]. Chapter Five is a computational study of the 5-endo-trig cyclisation of alkoxideallenes and amide-allenes, discussing the process involved (electron transfer or direct intramolecular anionic cyclisation) and comparing it with the, non-experimentally observed, 4-exo-dig cyclisation [DMSO graphic]. Chapter Six provides the detailed experimental procedures and data for the compounds that were synthesised and reported in this thesis.
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Buker, Nicholas D. "Guanidine donors in nonlinear optical chromophores /". Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/8669.
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Chua, Jonathan. "Exploring new reactions with Organic Electron Donors and the complexities of the Birch reduction". Thesis, University of Strathclyde, 2016. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=26437.
Abstract (sommario):
Reductive σ-bond cleavages of challenging substrates under metal-free, mild conditions have recently been achieved with photoactivated super-electron donor (SED). These include (but are not limited to) C-O bonds of benzylic ethers and esters, C-N bonds of benzylic sulfonamides and aromatic amides. This work has successfully widened the substrate scope of reduction by SED to include i) the C-O bond cleavages of phenolic esters and aryl ethers and ii) the C-S bond cleavages of aromatic sulfides, sulfoxides and sulfones. Previously it was also discovered that the X-N bond of several amides were reductively cleaved via intramolecular electron-shuttling instead of the more conventional through-bond electron transfer. This mode of reduction by SED is not well-explored. To this end, several ester and amide-based substrates were synthesised in an attempt to expand the scope of this electron-shuttling mechanism induced by SED. This study has also been successful, with the electron-shuttling effect thought to be responsible for the C-C bond cleavage of 14 [illustration not shown], resulting in the production of 15 [illustration not shown]. Perhaps the most powerful reducing agent in the synthetic industry is the "solvated electron" which is conveniently prepared during the Birch reduction. In this work, the Birch reduction conditions were successfuly applied, in an unprecedented way, to the C-S bond cleavage of methyl-coenzyme M (MeCoM). The experimental results have the potential to contribute significantly towards our current understanding of MeCoM reductase activity. This study has also highlighted the complex nature of the Birch reduction; by simply switching from sodium to lithium, reactivity and regioselectivity could be significantly altered. Presently, some details of the mechanism for the observed reduction(s) remain unsolved.
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Anderson, Greg. "Towards the rational development of organic super electron donors for transition metal-free biaryl coupling". Thesis, University of Strathclyde, 2016. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=27424.
Abstract (sommario):
Within both the industrial and academic laboratory, the coupling of two aryl moieties is a process of significant synthetic use. To achieve such transformations typically requires the use of expensive transition metal catalysts that cannot always be recovered from the reaction mixtures. Consequently, the investigation of biaryl coupling reactions without the requirement for any such catalysts has been of key interest amongst chemists. Throughout the literature, a variety of simple organic molecules have been incorrectly termed as “ligands” or “catalysts” with respect to their role in transition metal-free biaryl coupling reactions. We have discovered that these molecules in fact undergo reaction with a strong base to form an organic electron donor in situ, capable of reducing aryl iodides to their respective radical anions. This reduction can then initiate a cyclic radical reaction mechanism, furnishing the desired biaryl product. A number of key structures, identified through experimental studies, have helped to guide the early theoretical investigations. These allowed the feasibility of the formation of organic electron donors in situ, based on their free energy profiles, to be investigated. The mechanistic understanding gained from these calculations was then applied to rationalise the reactivity of other molecules shown to effectively promote this chemistry. To fully understand the reactivity in this chemistry, the computational application of Marcus Theory was called upon to predict the relative reducing ability of the proposed donor species. Shortcomings of the present protocol for the computational application of Marcus Theory prompted the development of a novel reaction model utilising electron transfer complexes. These complexes more accurately capture the internal reorganisation energy associated with the electron transfer reaction, affording calculated reaction energetics in stronger agreement with experiment. The foundations for the predictive application of this model to identify novel electron donors have been laid. Synthetic routes towards novel electron donor precursors have been identified for future work on this research.
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Tyree, William Stuart. "Correlation of Structure and Magnetic Properties in Charge-Transfer Salt Molecular Magnets Composed of Decamethylmetallocene Electron Donors and Organic Electron Acceptors". Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/34436.
Abstract (sommario):
Di-n-propyl dicyanofumarate (DnPrDCF) and di-isopropyl dicyanofumarate (DiPrDCF) have been used as one-electron acceptors in the synthesis of charge-transfer salt magnets with decamethylmetallocenes, MCp*2 (M = Mn, Cr). Salts of each acceptor with each metallocene have been characterized and the structures of the chromium analogues have been solved. The two acceptors are structurally similar to dimethyl dicyanofumarate (DMeDCF) and diethyl dicyanofumarate (DEtDCF), which have been previously studied and found to form charge-transfer salt magnets with the aforementioned decamethylmetallocenes. A typical structural motif is present in these types of charge-transfer salts which allows for the comparison of magnetic properties based on the length or size of the alkyl group of the dialkyl dicyanofumarate. Some trends were established based on the magnetic properties of the homologous series including ordering temperature/bulkiness of the alkyl group and intrastack distances/theta values. Correlation of magnetic and structural properties may give some insight into "through-space" magnetic coupling, of which little is understood.Master of Science
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Xu, Yunhua. "Synthesis and Photoinduced Electron Transfer of Donor-Sensitizer-Acceptor Systems". Doctoral thesis, Stockholm : Department of Organic Chemistry, Stockholm University, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-411.
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Fall, Arona. "Donneurs d’électrons organiques : développement d’un nouveau système catalytique photoredox". Electronic Thesis or Diss., Aix-Marseille, 2021. http://www.theses.fr/2021AIXM0607.
Abstract (sommario):
Durant ces dernières décennies, la réactivité des donneurs d’électrons organiques de type énamine (DEO) a été largement exploitée dans des réactions de réduction par transfert électronique. De part leurs forts pouvoir réducteur avec des potentiels redox exceptionellement négatifs, les DEOs sont capables de transférer spontanément un ou deux électrons à des substrats organiques, formant ainsi des intermédiaires radicalaires ou anioniques. Cependant, ces DEOs sont toujours utilisés en quantité stœchiométrique, ce qui limite leur compétivité face aux catalyseurs organométalliques et organiques.Les travaux de cette thèse consistent à répondre à cette problématique en développant un nouveau système catalytique avec ces DEOs. Pour cela, plusieurs stratégies ont été envisagées. Dans une première méthode, une quantité catalytique du DEO serait utilisée pour amorcer le transfert d’électron pour la réduction du substrat. L’oxydation d’intermédiaires radicalaires générés, permettrait alors de régénérer le DEO. Cette stratégie n’a malheureusement pas donné de résultat. Une seconde méthode consisterait à régénérer le DEO à partir de la forme oxydée DEO2+, stable à l’air et d’un donneur d’électron sacrificiel (amine tertiaire, dithionite de sodium ou Rongalite®) sous photoactivation. Plusieurs étapes d’optimisation ont permis d’aboutir à un système catalytique photoredox efficace avec la forme oxydée comme photocatalyseur et la Rongalite® en tant que donneur sacrificiel. Ce nouveau système catalytique photoredox a été appliqué à la réduction de divers groupements fonctionnels (sulfone, halogénure d’aryle, triflate) par transfert mono et biélectroniqueDuring this last decade, the reactivity of enamine-based organic electron donor (OED) has been widely explored in electron transfer processes. With exceptionally negative redox potentials, OEDs spontaneously promote single (SET) or double electron transfer (DET) to an organic substrate, to form radical or anionic intermediates. However, the use of stoichiometric amount of OEDs limits their competitivity compared to their organometallic and organic catalysts. This thesis project consisted in developing a new catalytic system with OEDs. Different strategies were envisaged. In a first method a catalytic amount of OED would initiate the electron transfer to reduce the substrate. The oxidation of the generated radical intermediate would allow the regeneration of OED. Unfortunately, this strategy was unsuccessful. The second strategy would consist in regenerating the OED from its air-stable oxidized form OED2+ and a sacrificial electron donor (tertiary amine, sodium dithionite or Rongalite®) under photoactivation. Several optimizing steps allowed the development of a new efficient catalytic photoredox system with the oxidized form as photocatalyst and Rongalite® as sacrificial electron donor. This new photoredox catalytic system was applied to the reduction of various functionals groups (sulfone, aryl halide and triflate) by single electron transfer (SET) and double electron transfer (DET). The reactivity of the photocatalytic system was also explored in radical addition reactions
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Aguiar, António Luís Gonçalves de. "New boron-dipyrromethene (BODIPY) molecules as suitable electron-donors for organic photovoltaic cells". Doctoral thesis, 2019. http://hdl.handle.net/10316/88807.
Abstract (sommario):
Tese no âmbito do Doutoramento em Química, Ramo de Especialização em Química Macromolecular apresentada ao Departamento de Química da Faculdade de Ciências e Tecnologia da Universidade de Coimbra.As células fotovoltaicas orgânicas (OPVs) têm surgido como uma das alternativas mais apelativas às células fotovoltaicas baseadas em semicondutores inorgânicos (essencialmente silício), devido ao baixo custo de produção, leveza, flexibilidade dos dispositivos e versatilidade na integração em edifícios. As moléculas de boro-dipirrometeno (BODIPY) são fotossensibilizadores muito promissores para aplicação em OPVs. Contudo, a aplicação de BODIPYs em células fotovoltaicas orgânicas começou a ser investigada há apenas 10 anos e o número de publicações é ainda relativamente baixo. Esta tese de doutoramento abrange a síntese, caracterização e aplicação fotovoltaica de várias moléculas de BODIPY divididas em quatro séries. A primeira série é composta maioritariamente por BODIPYs meso-substituídos cuja estrutura permite funcionalizações adicionais. Os resultados dos estudos das principais propriedades estruturais, fotofísicas, eletroquímicas, bem como os resultados dos testes fotovoltaicos serviram como base comparativa para a avaliação das moléculas subsequentes. As restantes três séries foram construídas a partir da funcionalização de algumas estruturas da primeira série. A segunda e terceira série são constituídas maioritariamente por novas estruturas com grupos estireno ou grupos vinílicos obtidos a partir da condensação de aldeídos aromáticos com alguns BODIPYs selecionados da primeira série, via condensação de Knoevenagel. Estes novos compostos possuem uma maior conjugação de eletrões-π e, por isso, uma absorção e emissão deslocadas para maiores comprimentos de onda. As moléculas de BODIPY da quarta série foram obtidas através da substituição dos ligandos típicos (átomos de flúor) por vários grupos ariloxi ou alcoxi. Adicionalmente, foram também sintetizadas três moléculas conjugadas de BODIPY-porfirina, usando um método de síntese já conhecido e um método alternativo desenvolvido ao longo do projeto doutoral. O novo método de síntese usa porfirinas com grupos carboxílicos para sintetizar BODIPYs diretamente ligados à estrutura das porfirinas. Além das técnicas de caracterização estrutural padrão (por exemplo, espectroscopia de ressonância magnética nuclear, espectrometria de massa), os compostos sintetizados foram estudados através de técnicas como termogravimetria, calorimetria diferencial de varredura, espectroscopia de absorção, espectroscopia de emissão, voltametria cíclica e estudos computacionais. A conjugação de todas as técnicas de caracterização permitiu obter um conhecimento abrangente das propriedades dos BODIPYs, calcular as energias das viii orbitais HOMO e LUMO, e avaliar a adequabilidade dos compostos para aplicação em OPVs. Todas as moléculas sintetizadas foram consideradas doadoras de eletrões adequadas (em combinação com os aceitadores de eletrões PC61BM e PC71BM) à aplicação em células fotovoltaicas orgânicas. Consequentemente, a maioria dos BODIPYs sintetizados foram testados e as melhores OPVs foram otimizadas em vários aspetos relativos à construção dos dispositivos. Em geral, as OPVs baseadas nas moléculas propostas apresentaram altas tensões de circuito aberto (VOC), e alguns sistemas atingiram eficiência de conversão de energia (PCE) acima de 2 %. O melhor resultado foi alcançado por um BODIPY com duas unidades de vinilnaftaleno, com um PCE de 2.8 % e VOC de 1.00 V, o que é uma eficiência muito promissora tendo em conta as OPVs baseadas em BODIPYs já publicadas, e um valor de VOC alto considerando qualquer tipo de célula fotovoltaica orgânica.
Organic photovoltaic cells (OPVs) have been arising as one of the most appealing alternatives to the photovoltaic cells based on inorganic semiconductors (mainly silicon) due to their low-cost production, lightweight, mechanical flexibility and versatility for building integration. Boron-dipyrromethene (BODIPY) molecules are auspicious photosensitizer materials for OPV. However, the research on BODIPY-based OPVs just started 10 years ago and the number of published studies is relatively low. This thesis comprises the synthesis, characterization and photovoltaic application of several BODIPY molecules divided into four different series. The first series is composed by simple meso-substituted BODIPY dyes whose molecular framework allows further derivatizations. The result of the studies of the main structural, photophysical, electrochemical properties as well as the photovoltaic results were used as standard data for performance evaluation of the subsequent series. The other three series are made of BODIPYs obtained upon functionalization of selected molecules from the first series. The second and third series are mostly constituted by new BODIPY structures with styryl or vinyl groups, synthesised through condensation of aromatic aldehydes with some selected BODIPY structures from the first series, via Knoevenagel condensation. These new molecules presented an expansion of the π-system which led to absorption and emission at higher wavelengths. The BODIPY molecules from the fourth series were obtained by changing the typical BODIPY’s boron ligands (fluorine atoms) by several aryloxy or alkoxy groups. Additionally, three BODIPY-porphyrin dyads were synthesised using both a reported pathway and a pathway developed during the PhD project. The new pathway uses porphyrins with carboxylic acid groups to synthesise the BODIPY structure directly attached to porphyrin’s structure. In addition to the standard structural characterisation (e.g. nuclear magnetic resonance spectroscopy, mass spectrometry), the synthesised compounds were characterised using a variety of techniques, namely, thermogravimetry, scanning calorimetry, absorption spectroscopy, emission spectroscopy, cyclic voltammetry and computational studies. The conjugation of all characterisation techniques allowed us to obtain a full understanding of their main properties, calculate the HOMO and LUMO energies and evaluate the suitability for application in OPVs. vi All the synthesised compounds were considered suitable electron-donors (upon combination with PC61BM and PC71BM as electron-acceptors) for organic photovoltaic cells. Consequently, almost all BODIPYs were tested and the best performing BODIPY-based OPVs were optimised in several aspects related to the engineering of the devices. In general, OPVs based on the proposed dyes presented high open-circuit voltages (VOC), and some systems reached power conversion efficiency (PCE) above 2 %. The best result was achieved by a BODIPY with two vinylnaphthalene units, with a PCE of 2.8 % and VOC of 1.00 V, which is a very promising PCE result for BODIPY-based OPV and a top VOC value for this sort of systems.
Libri sul tema "Organic electron donors (OEDs)":
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Ogura, F., e Y. Aso. Design of Novel Chalcogen-Containing Organic Metals: Extensively Conjugated Electron Donors and Acceptors with Reduced On-site Coulomb Repulsion. Taylor & Francis Group, 1992.
Capitoli di libri sul tema "Organic electron donors (OEDs)":
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Clark, K. F., D. Dimitrova e J. A. Murphy. "2.1 Organic Electron Donors in Electron-Transfer Reactions". In Free Radicals: Fundamentals and Applications in Organic Synthesis 2. Stuttgart: Georg Thieme Verlag KG, 2021. http://dx.doi.org/10.1055/sos-sd-233-00233.
Abstract (sommario):
AbstractThe field of organic electron donors is large and diverse, both in terms of the structures of the donors and the structures of the acceptors. In the past 15 years, organic donors have been developed that show remarkable strength, with ground-state or excited-state oxidation potentials rivalling even the most reactive metals. At the other end of the scale of reactivity, highly reactive oxidizing agents are now available upon photoactivation of a number of organic structures. The first part of this chapter reviews organic electron donors that are based upon an alkene that is activated by strongly electron-releasing substituents; these donors can be active in the ground and/or excited states. The chapter also covers anionic organic donors that emerged in the field of SRN1 and base-induced homolytic aromatic substitution (BHAS) reactions, as well as substrate-based anionic donors including borates and silicates. The use of photoexcited organic dyes as electron donors is described and, finally, some of the recent research with very weak organic donors is highlighted.
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"Conjugated Polymers as Electron Donors in Organic Solar Cells". In Organic Solar Cells, 24–39. CRC Press, 2017. http://dx.doi.org/10.1201/b18072-5.
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Ogura, Fumio, e Kazuo Takimiya. "Preparation of organic conductors". In Organoselenium Chemistry, 257–78. Oxford University PressOxford, 1999. http://dx.doi.org/10.1093/oso/9780198501411.003.0014.
Abstract (sommario):
Abstract Since the striking discovery of the charge-transfer (CT) complex of tetrathiafulvalene (TTF, 1) and 7,7,8,8-tetracyanoquinodimethane (TCNQ, 2) as the first synthetic metal, the development of novel electron donors and acceptors and the synthesis of organic metals and superconductors from them have aroused great interest among not only organic chemists but also scientists in many other interdisciplinary areas.
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Cook, Michael, e Philippa Cranwell. "Nucleophilic substitution". In Organic Chemistry, a cura di Elizabeth Page. Oxford University Press, 2017. http://dx.doi.org/10.1093/hesc/9780198729518.003.0003.
Abstract (sommario):
This chapter examines nucleophilic substitution. It begins by defining electrophiles and nucleophiles. An electrophile is a neutral or positively charged species with an empty orbital (or an energetically accessible anti-bonding orbital) which can accept electrons. Lewis acids can also be considered electrophiles as they have an empty orbital that can accept an electron pair. Meanwhile, a nucleophile contains a pair of electrons that can be used to form a new chemical bond. Nucleophiles thus act as electron donors. The chapter then looks at Lewis acids/bases.. The chapter then looks at Lewis acids/bases. It also considers SN1 and SN2, which are two classes of reaction that describe the nucleophilic substitution, or replacement, of one functional group at a saturated carbon centre by another. Finally, the chapter studies the impact of pK a on leaving group ability.
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Leonties, Anca R., Ludmila Aricov e Adina Raducan. "Electron Transfer". In Fundamental and Biomedical Aspects of Redox Processes, 344–68. IGI Global, 2023. http://dx.doi.org/10.4018/978-1-6684-7198-2.ch016.
Abstract (sommario):
Oxidoreductases are a special class of enzymes that use the redox mechanism for the efficient transformation of organic substrates. Most oxidoreductases contain metals in the active site and, for optimal functioning, require the participation of a small co-substrate with the ability to donate electrons. From the multitude of enzymes with economic and applicable potential, the authors focused their attention on three particular classes: catalases, peroxidases, and laccases. Catalases and peroxidases contain heme iron in their active sites and most often require electron donors such as oxygen or hydrogen peroxide while laccase contains copper and demands special co-substrates such as 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) or syringaldehyde. The theoretical aspects regarding the mechanism in which the electron transfer of the three enzymes is involved as well as the practical applications of the selected enzymes in the field of environmental remediation will be the subject of this chapter.
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Pope, Martin, e Charlese E. Swenberg. "Electronic processes in polyaniline (PAni)". In Electronic Processes in Organic Crystals and Polymers, 855–76. Oxford University PressNew York, NY, 1999. http://dx.doi.org/10.1093/oso/9780195129632.003.0010.
Abstract (sommario):
Abstract Among the most important polymeric conductors from the technological standpoint (as distinct from molecularly doped polymer films, which constitute the much more commercially important materials used in electrophotography) are the polyanilines. Polyanilines are a family of polymers of the general formula shown in Fig. X. l. These compounds have been known for more than 100 years as aniline blacks and are important dyestuffs. The great interest in these polymers at present is due to their ability to behave either as semiconductors or as metals, depending on the degree and type of doping used. The dopants are typical electron acceptors, such as AsF5 and electron donors, such as Li. Polyanilines have been used as active electrodes in lightweight rechargeable batteries, as hole-injecting electrodes in electroluminescent flexible LEDs, as a conductive adhesive, and in many other applications.
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Zaier, Rania, e Sahbi Ayachi. "Designing Well-Organized Donor-Bridge-Acceptor Conjugated Systems Based on Cyclopentadithiophene as Donors in Bulk Heterojunction Organic Solar Cells: DFT-Based Modeling and Calculations". In Solar Cells - Theory, Materials and Recent Advances. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.94874.
Abstract (sommario):
Two host materials based on CPDT as donors in bulk heterojunction organic solar cells were designed and investigated by means of DFT calculations. The first one (P-CPDTBT3) is a copolymer with D-A configuration and the second one (SM-CPDTDPP) is a D-π-A-π-D type small molecule. The investigated materials exhibited interesting structural properties with high planarity and rigidity originated from intra-molecular non-covalent interactions between the different building blocks. Thanks to their narrow band gaps, the optical absorption spectra have covered the main part of solar spectrum of interest. In addition, some general transport properties have been established. The transition density matrix (TDM) was used to get insight into the interaction of hole–electron localization and the electronic excitation processes. The photovoltaic parameters (FF, Voc) were calculated. The obtained results have been attempted to provide novel structure–property relationships for the rational design strategies of high-performance photovoltaic materials with power conversion efficiency of nearly 10%.
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Devikala, Sundaramurthy, e Johnson Maryleedarani Abisharani. "Addition of Organic Compounds in Gelatin-biopolymer Gel Electrolyte for Enhanced Dye-sensitized Solar Cells". In Advances in Solar Photovoltaic Energy Systems. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.1003045.
Abstract (sommario):
This chapter introduced a new series of organic compound additives like thiophene 2,5-dicarboxylic acid (TDA), sulfanilamide (SAA), 2,6-diamino pyridine (DAP), dibenzo-18-crown-6 (DBC) and 2,6-pyridine dicarboxylic acid (PDA) with gelatin/KI/I2 consist gel polymer electrolytes for dye-sensitized solar cells (DSSCs) application. Nowadays, it is focusing on biopolymers for preparing gel electrolytes for DSSCs application which is a conventional renewable energy source. Biopolymers are abundant in nature, and they are non-toxic, thermally stable, environmentally friendly, low-cost, and have good mechanical and physical properties. The introduced novel gelatin (GLN) biopolymer-based gel electrolytes play a role in improving ionic conductivity and stability, and it also play a better ability for ionic mobility. The low-cost and commercialized organic additive molecules with electron donors like S, O and N elements were strongly coordinated on the surface TiO2 and fermi level shift into negative potentials. The organic additive compound SAA achieved a very active additive and easily reduced the recombination reaction between the surface of TiO2 and I3− ions. This phenomenon readily improves the stability and overall η of the DSSC. During the DSSCs process, intrinsic charge carrier transfer between both electrodes as well as the continuous regeneration of the dye molecules. The surface study and conductivity of prepared gelatin-based gel electrolyte with N, S and O-based additives were characterized by fourier transform infrared spectroscopy (FTIR), UV-visible, X ray diifraction (XRD), Electrochemical Impedance Spectroscopy (EIS) and dye-sensitized solar cells (DSC), respectively. Furthermore, to examine the adsorption behaviour of organic additives on TiO2 (101) surface and negative fermi level shift on TiO2 surface were analysed by density functional theory (DFT) theoretical study.
Atti di convegni sul tema "Organic electron donors (OEDs)":
1
Gu, Qinying, e Dan Credgington. "Organic Photovoltaics Incorporating Electron Donors with Small Exchange Energy". In 1st International Conference on Advances in Organic and Hybrid Electronic Materials. València: Fundació Scito, 2019. http://dx.doi.org/10.29363/nanoge.aohm.2019.040.
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Sheats, John E., Andrew Jones, Albert Lang, Felicia Bland e Elizabeth Hernandez. "Organotransition Metal Complexes as π Acceptors in Non-linear Optical Materials". In Organic Thin Films for Photonic Applications. Washington, D.C.: Optica Publishing Group, 1993. http://dx.doi.org/10.1364/otfa.1993.wd.22.
Abstract (sommario):
Previous investigators 1-4 have employed ferrocenyl derivatives as strong π-electron donors in the preparation of highly conjugated organic molecules such as Ia-c with high values of the second order hyperpolarizability, β.
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Ahrens, Michael J., Michael J. Fuller e Michael R. Wasielewski. "Aminated and cyanated perylene mono- and diimides: Liquid crystalline electron donors and acceptors for organic photonics and electronics". In Frontiers in Optics. Washington, D.C.: OSA, 2003. http://dx.doi.org/10.1364/fio.2003.tuj5.
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Tian, Mingzhen, Baozhu Luo, Wenlian Li, Shihua Huang e Jiaqi Yu. "Persistent Photon-gated Spectral Holeburning In A New Donor-Acceptor Electron Transfer System". In Persistent Spectral Hole Burning: Science and Applications. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/pshb.1991.fa7.
Abstract (sommario):
Due to the interest in the frequency-domain optical storage application, recent researches on spectral holeburning concentrated on the two-colour photon-gated persistent holeburning[1,2]. Some organic systems have been investigated [3-7]. A representative one is TZT as a donor and CHCl3 as an acceptor in PMMA film undergoing donor-acceptor electron transfer, which offered a significant mechanism for persistent holeburning in organic system [4,5]. But there is an insurmountable problem in the system. As CHCl3 is volatile at room temperature, its concentration can not be controlled and the sample is difficult to further study. Here we report the holeburning system composed of metal-tetrabenzoporphyrin derivatives (MTBP) as the donors and a solid electron acceptor, p-hydroxybenzaldhyde (PHBA), which can easily be made into a stable "dry" film and in which the concentration of each component can be modified easily.
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Ehrlich, J., A. Heikal, Z. Y. Hu, I. Y. S. Lee, S. R. Marder, J. W. Perry, H. Röckel e X. L. Wu. "Nonlinear Spectroscopy and Applications of Two-Photon Absorbing Molecules". In Organic Thin Films for Photonic Applications. Washington, D.C.: Optica Publishing Group, 1997. http://dx.doi.org/10.1364/otfa.1997.tha.3.
Abstract (sommario):
Molecules exhibiting strong two-photon absorption hold great potential for a wide range of applications including: two-photon fluorescence microscopy, three-dimensional (3D) optical data storage, 3D microfabrication, and optical limiting. (1-4) From a fundamental point of view, knowledge of molecular two-photon spectra and structure/property relationships are also important for a more complete understanding of the third order polarizabilities of conjugated molecules. However, very little is known or understood about two-photon states and spectra of conjugated molecules or how they correlate with structure. We have observed large two-photon absorptivities in bis-donor diphenylpolyene derivatives, that appears to be correlated to simultaneous charge transfer from the end groups to the pi-conjugated bridge in the molecule. These molecules are also excellent photoexcitable electron donors that can initiate charge-transfer reactions. In initial applications of these materials we have demonstrated their use in two-photon initiation of polymerization and optical limiting.
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Rovira, C., J. Veciana, J. Tarres, N. SantaIo, E. Molins, M. Mas, D. O. Cowan, S. Yang e E. Canadell. "Towards tridimensional organic metals. synthesis and study of mlrlti sulfur /spl pi/-electron donors and their charge transfer complexes and salts". In International Conference on Science and Technology of Synthetic Metals. IEEE, 1994. http://dx.doi.org/10.1109/stsm.1994.835659.
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Jiang, Min-hua, Xu-tang Tao, Duo-rong Yuan, Nan Zhang e Dong Xu. "The Exploration of New Organic Crystals for Semiconductor Laser Second-Harmonic Generation". In Nonlinear Optics. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/nlo.1992.md31.
Abstract (sommario):
The demand for miniature blue and violet laser applications has stimulated the research on nonlinear optical crystals for semiconductor laser (800-1000nm) second-harmonic generation (SHG).This paper summarized our recent development on the exploration of new organic nonlinear optical (NLO) materials for such purposes. Based on the features of organic crystals and the requirements of semiconductor lasers to the corresponding SHG materials. The relations between the crystal sturcture and the spectral characteristics as well as the NLO properties of the organic corjugated molecules were investigated. The electron spectra of the donors and acceptors and their influence on the NLO properties were analyzed. According to these results. We have made an approach for solving the contradiction existed between the UV transmission range and the nonlinear conversion efficiency of the crystals i. e. Substituting the medium and weak donor-acceptor radicals into benzene- the organic conjugated matrix, to form benjene derivatives. Which may possess both large NLO coefficients and good UV transmission property, and satisfy the requirement for diode laser SHG applications.
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Patel, J. "Role of Plasma-Induced Liquid Chemistry for the Reduction Mechanism of Silver Ions to form Silver Nanostructures". In Functional Materials and Applied Physics. Materials Research Forum LLC, 2022. http://dx.doi.org/10.21741/9781644901878-7.
Abstract (sommario):
Abstract. There exists a variety of reports on the synthesis of silver nanostructures by plasma-liquid interactions; however seldom are those that discusses the underlying reaction kinetics. The present study focuses in such direction where the role of plasma-induced chemistry has been analysed in detail with the reports on the influence of radicals on the formation of silver nanostructures. The silver nanostructures are synthesized from various precursor concentrations of silver and characterized byultraviolet-visible spectroscopy and transmission electron microscopy analysis. Further, experiments have been carried out to clarify the role of reductants in silver nanostructures synthesis. It is found that hydrogen peroxide is unable to reduce the silver ions to silver atoms which is a necessary step to produce silver nanostructures. The addition of organic solvents such as methanol and ethanol has been found to enhance the production rate of silver nanostructures which indicates that methanol and ethanol are strong electron donors affecting the reduction process of silver ions. In order to probe the exact reaction mechanism for silver nanostructures synthesis, iodine has been used as hydrogen radical scavenger along with silver precursor solutions; however, it has been observed that addition of iodine ions generates a favourable condition for the reduction of silver ions. The ultraviolet-visible spectroscopy results indicate the existence of small clusters of silver ions and silver iodide and further transmission electron microscopy characterization suggests that a well-dispersed silver nanoparticles of less than 30 nm in size have been formed. The lattice spacing calculation from transmission electron microscopy images suggests the presence of crystallinity of the particles. Overall, it is found that there are two possible ways for the reduction mechanism of silver nanostructures: either via hydrated electrons or hydrogen radicals or both.
Rapporti di organizzazioni sul tema "Organic electron donors (OEDs)":
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Chefetz, Benny, Baoshan Xing, Leor Eshed-Williams, Tamara Polubesova e Jason Unrine. DOM affected behavior of manufactured nanoparticles in soil-plant system. United States Department of Agriculture, gennaio 2016. http://dx.doi.org/10.32747/2016.7604286.bard.
Abstract (sommario):
The overall goal of this project was to elucidate the role of dissolved organic matter (DOM) in soil retention, bioavailability and plant uptake of silver and cerium oxide NPs. The environmental risks of manufactured nanoparticles (NPs) are attracting increasing attention from both industrial and scientific communities. These NPs have shown to be taken-up, translocated and bio- accumulated in plant edible parts. However, very little is known about the behavior of NPs in soil-plant system as affected by dissolved organic matter (DOM). Thus DOM effect on NPs behavior is critical to assessing the environmental fate and risks related to NP exposure. Carbon-based nanomaterials embedded with metal NPs demonstrate a great potential to serve as catalyst and disinfectors. Hence, synthesis of novel carbon-based nanocomposites and testing them in the environmentally relevant conditions (particularly in the DOM presence) is important for their implementation in water purification. Sorption of DOM on Ag-Ag₂S NPs, CeO₂ NPs and synthesized Ag-Fe₃O₄-carbon nanotubebifunctional composite has been studied. High DOM concentration (50mg/L) decreased the adsorptive and catalytic efficiencies of all synthesized NPs. Recyclable Ag-Fe₃O₄-carbon nanotube composite exhibited excellent catalytic and anti-bacterial action, providing complete reduction of common pollutants and inactivating gram-negative and gram-positive bacteria at environmentally relevant DOM concentrations (5-10 mg/L). Our composite material may be suitable for water purification ranging from natural to the industrial waste effluents. We also examined the role of maize (Zeamays L.)-derived root exudates (a form of DOM) and their components on the aggregation and dissolution of CuONPs in the rhizosphere. Root exudates (RE) significantly inhibited the aggregation of CuONPs regardless of ionic strength and electrolyte type. With RE, the critical coagulation concentration of CuONPs in NaCl shifted from 30 to 125 mM and the value in CaCl₂ shifted from 4 to 20 mM. This inhibition was correlated with molecular weight (MW) of RE fractions. Higher MW fraction (> 10 kDa) reduced the aggregation most. RE also significantly promoted the dissolution of CuONPs and lower MW fraction (< 3 kDa) RE mainly contributed to this process. Also, Cu accumulation in plant root tissues was significantly enhanced by RE. This study provides useful insights into the interactions between RE and CuONPs, which is of significance for the safe use of CuONPs-based antimicrobial products in agricultural production. Wheat root exudates (RE) had high reducing ability to convert Ag+ to nAg under light exposure. Photo-induced reduction of Ag+ to nAg in pristine RE was mainly attributed to the 0-3 kDa fraction. Quantification of the silver species change over time suggested that Cl⁻ played an important role in photoconversion of Ag+ to nAg through the formation and redox cycling of photoreactiveAgCl. Potential electron donors for the photoreduction of Ag+ were identified to be reducing sugars and organic acids of low MW. Meanwhile, the stabilization of the formed particles was controlled by both low (0-3 kDa) and high (>3 kDa) MW molecules. This work provides new information for the formation mechanism of metal nanoparticles mediated by RE, which may further our understanding of the biogeochemical cycling and toxicity of heavy metal ions in agricultural and environmental systems. Copper sulfide nanoparticles (CuSNPs) at 1:1 and 1:4 ratios of Cu and S were synthesized, and their respective antifungal efficacy was evaluated against the pathogenic activity of Gibberellafujikuroi(Bakanae disease) in rice (Oryza sativa). In a 2-d in vitro study, CuS decreased G. fujikuroiColony- Forming Units (CFU) compared to controls. In a greenhouse study, treating with CuSNPs at 50 mg/L at the seed stage significantly decreased disease incidence on rice while the commercial Cu-based pesticide Kocide 3000 had no impact on disease. Foliar-applied CuONPs and CuS (1:1) NPs decreased disease incidence by 30.0 and 32.5%, respectively, which outperformed CuS (1:4) NPs (15%) and Kocide 3000 (12.5%). CuS (1:4) NPs also modulated the shoot salicylic acid (SA) and Jasmonic acid (JA) production to enhance the plant defense mechanisms against G. fujikuroiinfection. These results are useful for improving the delivery efficiency of agrichemicals via nano-enabled strategies while minimizing their environmental impact, and advance our understanding of the defense mechanisms triggered by the NPs presence in plants.