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Armando Gennaro

Bio: Armando Gennaro is an academic researcher from University of Padua. The author has contributed to research in topics: Atom-transfer radical-polymerization & Cyclic voltammetry. The author has an hindex of 52, co-authored 167 publications receiving 8788 citations. Previous affiliations of Armando Gennaro include Australian National University & Paris Diderot University.


Papers
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PatentDOI
16 Dec 2011-Science
TL;DR: In this article, the reduction of an ATRP catalyst, C 11 Br 2 /Me 6 TREN, is shown to be an efficient process to mediate and execute an AT RP.
Abstract: Electrochemical reduction of an exemplary ATRP catalyst, C 11 Br 2 /Me 6 TREN, is shown to be an efficient process to mediate and execute an ATRP. The onset of polymerization occurs only through passage of a cathodic current achieved under a reductive potential to form Cu 1 Br 2 /Me 6 TREN, within the reaction medium. Unprecedented control over the polymerization kinetics can be attained through electrochemical methods by modulating the magnitude of the applied potential allowing polymerization rate enhancement or retardation. Additional polymerization control is gained through electrochemical “dials” allowing polymerization rate enhancements achieved by larger applied potentials and the ability to successfully switch a polymerization “on” and “off between dormant and active states by application of multistep intermittent potentials.

599 citations

Journal ArticleDOI
TL;DR: The absolute potential of the standard hydrogen electrode, SHE, was calculated on the basis of a thermodynamic cycle involving H(2(g)) atomization, ionization of H((g))* to H(( g))(+), and hydration of H(+) to obtain a SHE value based on the chemical potential.
Abstract: The absolute potential of the standard hydrogen electrode, SHE, was calculated on the basis of a thermodynamic cycle involving H2(g) atomization, ionization of H(g)• to H(g)+, and hydration of H+. The most up-to-date literature values on the free energies of these reactions have been selected and, when necessary, adjusted to the electron convention Fermi−Dirac statistics since both e− and H+ are fermions. As a reference state for the electron, we have chosen the electron at 0 K, which is the one used in computational chemistry. Unlike almost all previous estimations of SHE, ΔGaq⊖(H+) was used instead of the real potential, αaq(H+). This choice was made to obtain a SHE value based on the chemical potential, which is the appropriate reference to be used in theoretical computations of standard reduction potentials. The result of this new estimation is a value of 4.281 V for the absolute potential of SHE. The problem of conversion of standard reduction potentials (SRPs) measured or estimated in water to the c...

375 citations

Journal ArticleDOI
TL;DR: A deeper understanding of the chemical processes of metal-free ATRP is provided that can aid the design of better catalytic systems and elucidates several important common pathways involved in synthetically useful organic reactions catalyzed by photoredox catalysts.
Abstract: Photoinduced metal-free atom transfer radical polymerization (ATRP) of methyl methacrylate was investigated using several phenothiazine derivatives and other related compounds as photoredox catalysts. The experiments show that all selected catalysts can be involved in the activation step, but not all of them participated efficiently in the deactivation step. The redox properties and the stability of radical cations derived from the catalysts were evaluated by cyclic voltammetry. Laser flash photolysis (LFP) was used to determine the lifetime and activity of photoexcited catalysts. Kinetic analysis of the activation reaction according to dissociative electron-transfer (DET) theory suggests that the activation occurs only with an excited state of catalyst. Density functional theory (DFT) calculations revealed the structures and stabilities of the radical cation intermediates as well as the reaction energy profiles of deactivation pathways with different photoredox catalysts. Both experiments and calculation...

347 citations

Journal ArticleDOI
TL;DR: The mechanism of reversible deactivation radical polymerization (RDRP) in the presence of Cu0 has been extensively studied in the literature as mentioned in this paper, with a variety of mechanisms proposed.
Abstract: Reversible-deactivation radical polymerization (RDRP) in the presence of Cu0 is a versatile technique that can be used to create well-controlled polymers with complex architectures. Despite the facile nature of the technique, there has been a vigorous debate in the literature as to the mechanism of the reaction. One proposed mechanism, named supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP), has CuI as the major activator of alkyl halides, Cu0 acting as a supplemental activator, an inner-sphere electron transfer occurring during the activation step, and relatively slow comproportionation and disproportionation. In SARA ATRP slow activation of alkyl halides by Cu0 and comproportionation of CuII with Cu0 compensates for the small number of radicals lost to termination reactions. Alternatively, a mechanism named single electron transfer living radical polymerization (SET-LRP) assumes that the CuI species do not activate alkyl halides, but undergo instantaneous disprop...

261 citations

Journal ArticleDOI
TL;DR: In this paper, a review of electrochemically mediated atom transfer radical polymerization (eATRP) setup is discussed in detail, together with the advantages and limitations of this technique.

260 citations


Cited by
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Journal ArticleDOI
TL;DR: An overview of the basic photophysics and electron transfer theory is presented in order to provide a comprehensive guide for employing this class of catalysts in photoredox manifolds.
Abstract: In this review, we highlight the use of organic photoredox catalysts in a myriad of synthetic transformations with a range of applications. This overview is arranged by catalyst class where the photophysics and electrochemical characteristics of each is discussed to underscore the differences and advantages to each type of single electron redox agent. We highlight both net reductive and oxidative as well as redox neutral transformations that can be accomplished using purely organic photoredox-active catalysts. An overview of the basic photophysics and electron transfer theory is presented in order to provide a comprehensive guide for employing this class of catalysts in photoredox manifolds.

3,550 citations

Journal ArticleDOI
TL;DR: The challenges in achieving highly active and stable CO2 reduction electrocatalysts are analyzed, and several research directions for practical applications are proposed, with the aim of mitigating performance degradation, overcoming additional challenges, and facilitating research and development in this area.
Abstract: This paper reviews recent progress made in identifying electrocatalysts for carbon dioxide (CO2) reduction to produce low-carbon fuels, including CO, HCOOH/HCOO−, CH2O, CH4, H2C2O4/HC2O4−, C2H4, CH3OH, CH3CH2OH and others. The electrocatalysts are classified into several categories, including metals, metal alloys, metal oxides, metal complexes, polymers/clusters, enzymes and organic molecules. The catalyts' activity, product selectivity, Faradaic efficiency, catalytic stability and reduction mechanisms during CO2 electroreduction have received detailed treatment. In particular, we review the effects of electrode potential, solution–electrolyte type and composition, temperature, pressure, and other conditions on these catalyst properties. The challenges in achieving highly active and stable CO2 reduction electrocatalysts are analyzed, and several research directions for practical applications are proposed, with the aim of mitigating performance degradation, overcoming additional challenges, and facilitating research and development in this area.

2,205 citations

Journal ArticleDOI
TL;DR: The current status and future perspectives in atom transfer radical polymerization (ATRP) are presented in this paper, with a special emphasis on mechanistic understanding of ATRP, recent synthetic and process development, and new controlled polymer architectures enabled by ATRP.
Abstract: Current status and future perspectives in atom transfer radical polymerization (ATRP) are presented. Special emphasis is placed on mechanistic understanding of ATRP, recent synthetic and process development, and new controlled polymer architectures enabled by ATRP. New hybrid materials based on organic/inorganic systems and natural/synthetic polymers are presented. Some current and forthcoming applications are described.

2,188 citations

Journal ArticleDOI
TL;DR: This review discusses advances in synthetic organic electrochemistry since 2000 with enabling methods and synthetic applications analyzed alongside innate advantages as well as future challenges of electroorganic chemistry.
Abstract: Electrochemistry represents one of the most intimate ways of interacting with molecules. This review discusses advances in synthetic organic electrochemistry since 2000. Enabling methods and synthetic applications are analyzed alongside innate advantages as well as future challenges of electroorganic chemistry.

1,930 citations

Journal ArticleDOI
TL;DR: Providing a future energy supply that is secure and CO_2-neutral will require switching to nonfossil energy sources such as wind, solar, nuclear, and geothermal energy and developing methods for transforming the energy produced by these new sources into forms that can be stored, transported, and used upon demand.
Abstract: Two major energy-related problems confront the world in the next 50 years. First, increased worldwide competition for gradually depleting fossil fuel reserves (derived from past photosynthesis) will lead to higher costs, both monetarily and politically. Second, atmospheric CO_2 levels are at their highest recorded level since records began. Further increases are predicted to produce large and uncontrollable impacts on the world climate. These projected impacts extend beyond climate to ocean acidification, because the ocean is a major sink for atmospheric CO2.1 Providing a future energy supply that is secure and CO_2-neutral will require switching to nonfossil energy sources such as wind, solar, nuclear, and geothermal energy and developing methods for transforming the energy produced by these new sources into forms that can be stored, transported, and used upon demand.

1,651 citations