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174 results on '"Moonshiram, Dooshaye"'

1. Attosecond dispersive soft X-ray absorption fine structure spectroscopy in graphite

Author

Buades, Bárbara, Moonshiram, Dooshaye, Sidiropoulos, Themistoklis P. H., León, Iker, Schmidt, Peter, Pi, Irina, Di Palo, Nicola, Cousin, Seth L., Picón, Antonio, Koppens, Frank, and Biegert, Jens

Subjects
Condensed Matter - Materials Science
Abstract

Phase transitions of solids and structural transformations of molecules are canonical examples of important photo-induced processes, whose underlying mechanisms largely elude our comprehension due to our inability to correlate electronic excitation with atomic position in real time. Here, we present a decisive step towards such new methodology based on water-window-covering (284 eV to 543 eV) attosecond soft X-ray pulses that can simultaneously access electronic and lattice parameters via dispersive X-ray absorption fine-structure (XAFS) spectroscopy. We validate attoXAFS with an identification of the {\sigma}* and {\pi}* orbital contributions to the density of states in graphite simultaneously with its lattice's four characteristic bonding distances. This work demonstrates the concept of attoXAFS as a powerful real-time investigative tool which is equally applicable to gas-, liquid- and condensed phase.

Published
2018
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2. Spectroscopic characterization and reactivity studies of a copper(II) iminoxyl radical complex.

Author

Kaur, Simarjeet, Das, Avijit, Velasco, Lucia, Sauvan, Maxime, Bera, Moumita, Ugale, Ashok, Charisiadis, Asterios, Moonshiram, Dooshaye, and Paria, Sayantan

Subjects
REORGANIZATION energy, SYNTHETIC proteins, X-ray absorption, RADICALS (Chemistry), X-ray spectroscopy
Abstract

A CuII complex (1) of a bis-pyridine-dioxime ligand and its one-electron oxidized analog (1-ox) were thoroughly characterized by various spectroscopic techniques, including X-ray absorption spectroscopy. 1-ox was found to be a CuII complex of a ligand iminoxyl radical and represents the first example of such a type. Reorganization energy (λ) of 2.12 eV was determined for the 1-ox/1 couple, which is considerably higher than the type 1 protein and synthetic CuIII/II(OH) complexes. [ABSTRACT FROM AUTHOR]

Published
2024
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6. Water oxidation electrocatalysis using ruthenium coordination oligomers adsorbed on multiwalled carbon nanotubes

Author

Hoque, Md Asmaul, Gil-Sepulcre, Marcos, de Aguirre, Adiran, Elemans, Johannes A. A. W., Moonshiram, Dooshaye, Matheu, Roc, Shi, Yuanyuan, Benet-Buchholz, Jordi, Sala, Xavier, Malfois, Marc, Solano, Eduardo, Lim, Joohyun, Garzón-Manjón, Alba, Scheu, Christina, Lanza, Mario, Maseras, Feliu, Gimbert-Suriñach, Carolina, and Llobet, Antoni

Published
2020
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7. Directed Electron Delivery from a Pb‐Free Halide Perovskite to a Co(II) Molecular Catalyst Boosts CO2 Photoreduction Coupled with Water Oxidation.

Author

Zhao, Jin‐Shuang, Mu, Yan‐Fei, Wu, Li‐Yuan, Luo, Zhi‐Mei, Velasco, Lucia, Sauvan, Maxime, Moonshiram, Dooshaye, Wang, Jia‐Wei, Zhang, Min, and Lu, Tong‐Bu

Subjects
OXIDATION of water, COBALT catalysts, PHOTOCATALYSIS, PEROVSKITE, ELECTRONS, PHOTOREDUCTION, PHOTOCATALYTIC oxidation
Abstract

The development of high‐performance photocatalytic systems for CO2 reduction is appealing to address energy and environmental issues, while it is challenging to avoid using toxic metals and organic sacrificial reagents. We here immobilize a family of cobalt phthalocyanine catalysts on Pb‐free halide perovskite Cs2AgBiBr6 nanosheets with delicate control on the anchors of the cobalt catalysts. Among them, the molecular hybrid photocatalyst assembled by carboxyl anchors achieves the optimal performance with an electron consumption rate of 300±13 μmol g−1 h−1 for visible‐light‐driven CO2‐to‐CO conversion coupled with water oxidation to O2, over 8 times of the unmodified Cs2AgBiBr6 (36±8 μmol g−1 h−1), also far surpassing the documented systems (<150 μmol g−1 h−1). Besides the improved intrinsic activity, electrochemical, computational, ex‐/in situ X‐ray photoelectron and X‐ray absorption spectroscopic results indicate that the electrons photogenerated at the Bi atoms of Cs2AgBiBr6 can be directionally transferred to the cobalt catalyst via the carboxyl anchors which strongly bind to the Bi atoms, substantially facilitating the interfacial electron transfer kinetics and thereby the photocatalysis. [ABSTRACT FROM AUTHOR]

Published
2024
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9. Precious-Metal-Free CO2 Photoreduction Boosted by Dynamic Coordinative Interaction between Pyridine-Tethered Cu(I) Sensitizers and a Co(II) Catalyst

Author

Wang, Jia-Wei, primary, Zhang, Xian, additional, Velasco, Lucia, additional, Karnahl, Michael, additional, Li, Zizi, additional, Luo, Zhi-Mei, additional, Huang, Yanjun, additional, Yu, Jin, additional, Hu, Wenhui, additional, Zhang, Xiaoyi, additional, Yamauchi, Kosei, additional, Sakai, Ken, additional, Moonshiram, Dooshaye, additional, and Ouyang, Gangfeng, additional

Published
2023
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10. Functional Model of Compound II of Cytochrome P450: Spectroscopic Characterization and Reactivity Studies of a FeIV–OH Complex

Author

Keshari, Kritika, Santra, Aakash, Velasco, Lucía, Sauvan, Maxime, Kaur, Simarjeet, Ugale, Ashok D., Munshi, Sandip, Marco, J. F., Moonshiram, Dooshaye, and Paria, Sayantan

Abstract

Herein, we show that the reaction of a mononuclear FeIII(OH) complex (1) with N-tosyliminobenzyliodinane (PhINTs) resulted in the formation of a FeIV(OH) species (3). The obtained complex 3was characterized by an array of spectroscopic techniques and represented a rare example of a synthetic FeIV(OH) complex. The reaction of 1with the one-electron oxidizing agent was reported to form a ligand-oxidized FeIII(OH) complex (2). 3revealed a one-electron reduction potential of −0.22 V vs Fc+/Fc at −15 °C, which was 150 mV anodically shifted than 2(Ered= −0.37 V vs Fc+/Fc at −15 °C), inferring 3to be more oxidizing than 2. 3reacted spontaneously with (4-OMe-C6H4)3C•to form (4-OMe-C6H4)3C(OH) through rebound of the OH group and displayed significantly faster reactivity than 2. Further, activation of the hydrocarbon C–H and the phenolic O–H bond by 2and 3was compared and showed that 3is a stronger oxidant than 2. A detailed kinetic study established the occurrence of a concerted proton–electron transfer/hydrogen atom transfer reaction of 3. Studying one-electron reduction of 2and 3using decamethylferrocene (Fc*) revealed a higher ketof 3than 2. The study established that the primary coordination sphere around Fe and the redox state of the metal center is very crucial in controlling the reactivity of high-valent Fe–OH complexes. Further, a FeIII(OMe) complex (4) was synthesized and thoroughly characterized, including X-ray structure determination. The reaction of 4with PhINTs resulted in the formation of a FeIV(OMe) species (5), revealing the presence of two FeIVspecies with isomer shifts of −0.11 mm/s and = 0.17 mm/s in the Mössbauer spectrum and showed FeIV/FeIIIpotential at −0.36 V vs Fc+/Fc couple in acetonitrile at −15 °C. The reactivity studies of 5were investigated and compared with the FeIV(OH) complex (3).

Published
2024
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11. Impaired conjugation boosts CO2 electroreduction by Ni(ii) macrocyclic catalysts immobilized on carbon nanotubes

Author

Huang, Y., Dai, H., Moonshiram, Dooshaye, Li, Z., Luo, Z.-M., Zhang, J.-H., Yang, W., Shen, Y., Wang, J.-W., Ouyang, G., Huang, Y., Dai, H., Moonshiram, Dooshaye, Li, Z., Luo, Z.-M., Zhang, J.-H., Yang, W., Shen, Y., Wang, J.-W., and Ouyang, G.

Abstract

Metal complexes hybridized with conductive supports are desirable as high-performance catalysts for CO2 electroreduction, while the delicate molecular design to improve both the intrinsic activity of complex and the molecule-support interactions still remains challenging. We here employ a conjugation-tuning strategy by comparison between Ni(ii) octabutoxyphthalocyanine and Ni(ii) octabutoxynaphthalocyanine on multi-walled carbon nanotubes (NiPc-B@CNT and NiNc-B@CNT) in aqueous electrocatalytic CO2 reduction, respectively. In contrast to the conventional promotive effects from extended conjugation, the impaired conjugation in the Ni(ii) macrocycles unusually boosts both activity and molecule-support affinity. These merits can be attributed to the favored electronic effects and the higher flexibility of long alkyl chains both arising from the absent extended benzene ring in NiPc-B. Consequently, NiPc-B@CNT exhibits much higher faradaic efficiencies for CO production (FECO ≥ 94% among −0.79 to −1.09 V vs. RHE) than NiNc-B@CNT (FECO < 20%) in an H-cell configuration. The use of a gas-diffusion electrode further raises the electrocatalytic performances of NiPc-B@CNT under 1 atm CO2 (FECO ≈ 100% at −0.15 A cm−2) or simulated flue gas (10% CO2, FECO ≈ 80% at −0.1 A cm−2), respectively. © 2023 The Royal Society of Chemistry.

Published
2023

18. Deciphering the photophysical kinetics, electronic configurations and structural conformations of iridium–cobalt hydrogen evolution photocatalysts

Author

UCL - SST/IMCN/MOST - Molecular Chemistry, Materials and Catalysis, Zhao, Jiangyun, De Kreijger, Simon, Troian-Gautier, Ludovic, Yu, Jin, Hu, Wenhui, Zhang, Xiaoyi, Elias, Benjamin, Moonshiram, Dooshaye, UCL - SST/IMCN/MOST - Molecular Chemistry, Materials and Catalysis, Zhao, Jiangyun, De Kreijger, Simon, Troian-Gautier, Ludovic, Yu, Jin, Hu, Wenhui, Zhang, Xiaoyi, Elias, Benjamin, and Moonshiram, Dooshaye

Abstract

Picosecond optical and X-ray absorption spectroscopies with time- dependent density functional theory revealed the reaction pathways, electronic and structural conformations of Ir–Co hydrogen evolution photocatalysts. The dyad bearing 2-phenylpyridine ancillary ligands produced more photoreduced Co(II) than its 2-phenylisoquinoline analogue. These findings are important for designs of earth- abundant photosensitizers for photocatalytic applications.

Published
2022

19. Magnetic mechanically-interlocked porphyrin-carbon nanotubes

Author

Moreno-Da Silva, Sara, Martínez, Jesús I., Develioglu, Aysegul, Nieto-Ortega, Belén, Juan-Fernández, Leire de, Ruiz-Gonzalez, Luisa, Picón, Antonio, Oberli, Soléne, Alonso, Pablo J., Moonshiram, Dooshaye, Pérez, Emilio M., Burzurí, Enrique, Moreno-Da Silva, Sara, Martínez, Jesús I., Develioglu, Aysegul, Nieto-Ortega, Belén, Juan-Fernández, Leire de, Ruiz-Gonzalez, Luisa, Picón, Antonio, Oberli, Soléne, Alonso, Pablo J., Moonshiram, Dooshaye, Pérez, Emilio M., and Burzurí, Enrique

Abstract

Magnetic molecules have been proposed as versatile building blocks for quantum computing and molecular spintronics devices. The molecular spin can be used to encode quantum information in qubits or even perform logic operations as quantum gates with unmatched reproducibility and scalability. In spintronics, that same molecular spin can be used to generate spin currents in molecular based spin filters, spin switches or spin valves in carbon-nanotube/molecule hybrids, among other applications. Several strategies have been followed to couple the magnetic molecules to carbon nanotubes: direct physisorption of the molecules, covalent bonding or encapsulation of the magnetic molecules. We have developed the synthesis of mechanically interlocked rotaxane-like SWCNT derivatives (MINTs), in which the ring-closing metathesis of a U-shape molecule around SWCNTs is templated. In particular, we fabricated Cu2+ and Co2+ metalloporphyrin dimer rings mechanically interlocked around carbon nanotubes to form magnetic MINTs (mMINT). Magnetic porphyrins are selected due to their recently proved suitability as qubits, even preserving their magnetic properties and quantum coherence on surfaces. The mechanical bond places the porphyrin magnetic cores in close contact with the SWCNT without disturbing the molecular spin nor the carbon nanotube structure. The magnetic properties of the metallic dimers are preserved upon formation the mechanically interlocked hybrid.

Published
2022

21. Photocatalytic CO2 reduction with a quantum efficiency exceeding 60%: time-resolved spectroscopic and X-ray studies on Cu(I) photosensitizers in coordinative interaction with Co(II) phthalocyanine catalysts

Author

Wang, Jia-Wei, primary, Zhang, Xian, additional, Karnahl, Michael, additional, Luo, Zhi-Mei, additional, Li, Zizi, additional, Huang, Yanjun, additional, Yu, Jin, additional, Hu, Wenhui, additional, Zhang, Xiaoyi, additional, Moonshiram, Dooshaye, additional, and Ouyang, Gangfeng, additional

Published
2022
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23. Impaired conjugation boosts CO2 electroreduction by Ni(II) macrocyclic catalysts immobilized on carbon nanotubes.

Author

Huang, Yanjun, Dai, Hao, Moonshiram, Dooshaye, Li, Zhuofeng, Luo, Zhi-Mei, Zhang, Ji-Hong, Yang, Wenxing, Shen, Yong, Wang, Jia-Wei, and Ouyang, Gangfeng

Abstract

Metal complexes hybridized with conductive supports are desirable as high-performance catalysts for CO2 electroreduction, while the delicate molecular design to improve both the intrinsic activity of complex and the molecule–support interactions still remains challenging. We here employ a conjugation-tuning strategy by comparison between Ni(II) octabutoxyphthalocyanine and Ni(II) octabutoxynaphthalocyanine on multi-walled carbon nanotubes (NiPc-B@CNT and NiNc-B@CNT) in aqueous electrocatalytic CO2 reduction, respectively. In contrast to the conventional promotive effects from extended conjugation, the impaired conjugation in the Ni(II) macrocycles unusually boosts both activity and molecule–support affinity. These merits can be attributed to the favored electronic effects and the higher flexibility of long alkyl chains both arising from the absent extended benzene ring in NiPc-B. Consequently, NiPc-B@CNT exhibits much higher faradaic efficiencies for CO production (FECO ≥ 94% among −0.79 to −1.09 V vs. RHE) than NiNc-B@CNT (FECO < 20%) in an H-cell configuration. The use of a gas-diffusion electrode further raises the electrocatalytic performances of NiPc-B@CNT under 1 atm CO2 (FECO ≈ 100% at −0.15 A cm−2) or simulated flue gas (10% CO2, FECO ≈ 80% at −0.1 A cm−2), respectively. [ABSTRACT FROM AUTHOR]

Published
2023
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25. Magnetic, Mechanically Interlocked Porphyrin–Carbon Nanotubes for Quantum Computation and Spintronics

Author

Moreno-Da Silva, Sara, primary, Martínez, Jesús I., additional, Develioglu, Aysegul, additional, Nieto-Ortega, Belén, additional, de Juan-Fernández, Leire, additional, Ruiz-Gonzalez, Luisa, additional, Picón, Antonio, additional, Oberli, Soléne, additional, Alonso, Pablo J., additional, Moonshiram, Dooshaye, additional, Pérez, Emilio M., additional, and Burzurí, Enrique, additional

Published
2021
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26. Surface-Promoted Evolution of Ru-bda Coordination Oligomers Boosts the Efficiency of Water Oxidation Molecular Anodes

Author

Gil-Sepulcre, Marcos, primary, Lindner, Joachim O., additional, Schindler, Dorothee, additional, Velasco, Lucía, additional, Moonshiram, Dooshaye, additional, Rüdiger, Olaf, additional, DeBeer, Serena, additional, Stepanenko, Vladimir, additional, Solano, Eduardo, additional, Würthner, Frank, additional, and Llobet, Antoni, additional

Published
2021
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28. Electrochemically and Photochemically Induced Hydrogen Evolution Catalysis with Co-Tetraazamacrocycles Occur via Different Pathways

Author

Grau, Sergi, Schilling, Mauro, Moonshiram, Dooshaye, Benet-Buchholz, Jordi, Luber, Sandra, Llobet, Antoni, and Gimbert-Suriñach, Carolina

Abstract

Cobalt complexes containing equatorial tetraazamacrocyclic ligands are active catalysts for the hydrogen evolution reaction in pure aqueous conditions. Herein we explore the effect of different groups directly linked to the macrocyclic ligand (- NH-, -NH2+- or –N(CH2OH)-). Electrochemically induced hydrogen evolution catalysis studies at pH 4 invoke a mechanism, in which the rate determining step is the protonation of the reduced CoI species that gives a cobalt hydride (CoIII-H), a key intermediate towards the H- H bond formation. In sharp contrast, under photochemical conditions using [Ru(bpy)3]2+ as a photosensitizer and ascorbate as sacrificial electron donor, the formation of a “Co0” species that quickly protonates to give a CoII-H is proposed. In this scenario, the rate determining step is the H-H bond formation that occurs in an intermolecular fashion from the CoII-H species and a water molecule. Both mechanisms are supported by density functional theory (DFT) calculations that allowed us to estimate the pKa values of the CoIII-H and CoII-H species, as well as transition states based on intramolecular and intermolecular H-H bond formation from CoII-H.

Published
2020

33. Tracking the Light‐Induced Excited‐State Dynamics and Structural Configurations of an Extraordinarily Long‐Lived Metastable State at Room Temperature

Author

Iglesias, Sirma, primary, Gamonal, Arturo, additional, Abudulimu, Abasi, additional, Picón, Antonio, additional, Carrasco, Esther, additional, Écija, David, additional, Liu, Cunming, additional, Luer, Larry, additional, Zhang, Xiaoyi, additional, Costa, José Sánchez, additional, and Moonshiram, Dooshaye, additional

Published
2020
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36. Cover Feature: Spectroscopic Characterisation of a Bio‐Inspired Ni‐Based Proton Reduction Catalyst Bearing a Pentadentate N2S3 Ligand with Improved Photocatalytic Activity (Chem. Eur. J. 13/2020)

Author

Gotico, Philipp, primary, Moonshiram, Dooshaye, additional, Liu, Cunming, additional, Zhang, Xiaoyi, additional, Guillot, Régis, additional, Quaranta, Annamaria, additional, Halime, Zakaria, additional, Leibl, Winfried, additional, and Aukauloo, Ally, additional

Published
2020
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38. 3343287.pdf

Author

Buades, Barbara, Moonshiram, Dooshaye, Sidiropoulos, Themistoklis, Leon, Iker, Schmidt, Peter, Pi, Irina, Di Palo, Nicola, Cousin, Seth, Picón, Antonio, and Koppens, Frank

Abstract

Supplementary Information

Published
2018
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39. Disseny d'un ànode molecular capaç de realitzar un milió de cicles en la catàlisi d'oxidació d'aigua

Author

Creus i Muncunill, Jordi, Matheu, Roc, Peñafield, Itziar, Moonshiram, Dooshaye, Blondeau, Pascal, Benet Buchholz, Jordi, García-Antón Aviñó, Jordi, Sala Román, Xavier, Godard, Cyril, and Llobet, Antoni

Abstract

L'obtenció de H2 com a vector energètic a partir de l'aigua i l'energia solar és una alternativa interessant als combustibles fòssils. La seva obtenció a través de la dissociació de l'aigua (water splitting) requereix catalitzadors que disminueixin la barrera energètica de les dues semireaccions involucrades: l'oxidació de l'aigua a O2 i la reducció de protons a H2. El desenvolupament de nous catalitzadors permet millorar el coneixement dels mecanismes de reacció i dissenyar-ne de nous amb propietats catalítiques avançades. En aquest treball presentem la immobilització d'un complex molecular altament actiu en l'oxidació de l'aigua, el qual és capaç de fer un milió de cicles catalítics., Molecular hydrogen is a promising candidate for replacing fossil fuels. The production of this gas by water splitting requires catalysts to speed up the respective semi-reactions: oxidation of water to O2 and reduction of protons to H2. The development of these catalysts helps to provide a better understanding of the catalytic pathways, allowing the rational design of new active species. In this study the immobilization of a highly active water oxidation molecular catalyst is achieved, reaching over 1 million TONs under catalytic conditions. Keywords: Water oxidation, catalyst immobilization

Published
2018

40. Disseny d’un ànode molecular capaç de realitzar un milió de cicles en la catàlisi d’oxidació d’aigua

Author

Creus, Jordi, Matheu, Roc, Peñafiel, Itziar, Moonshiram, Dooshaye, Blondeau, Pascal, Benet-Buchholz, Jordi, García-Antón, Jordi, Sala, Xavier, Godard, Cyril, Llobet, Antoni, Creus, Jordi, Matheu, Roc, Peñafiel, Itziar, Moonshiram, Dooshaye, Blondeau, Pascal, Benet-Buchholz, Jordi, García-Antón, Jordi, Sala, Xavier, Godard, Cyril, and Llobet, Antoni

Abstract

L’obtenció de H2 com a vector energètic a partir de l’aigua i l’energia solar és una alternativa interessant als combustibles fòssils. La seva obtenció a través de la dissociació de l’aigua (water splitting) requereix catalitzadors que disminueixin la barrera energètica de les dues semireaccions involucrades: l’oxidació de l’aigua a O2 i la reducció de protons a H2. El desenvolupament de nous catalitzadors permet millorar el coneixement dels mecanismes de reacció i dissenyar-ne de nous amb propietats catalítiques avançades. En aquest treball presentem la immobilització d’un complex molecular altament actiu en l’oxidació de l’aigua, el qual és capaç de fer un milió de cicles catalítics.Paraules clau: Oxidació d’aigua, immobilització de catalitzadors, ruteni, dissociació de l’aigua, water splitting., Molecular hydrogen is a promising candidate for replacing fossil fuels. The production of this gas by water splitting requires catalysts to speed up the respective semi-reactions: oxidation of water to O2 and reduction of protons to H2. The development of these catalysts helps to provide a better understanding of the catalytic pathways, allowing the rational design of new active species. In this study the immobilization of a highly active water oxidation molecular catalyst is achieved, reaching over 1 million TONs under catalytic conditions.Keywords: Water oxidation, catalyst immobilization, ruthenium, water splitting.

Published
2018

41. The Coordination Behaviour of CuI Photosensitizers Bearing Multidentate Ligands Investigated by X‐ray Absorption Spectroscopy.

Author

Rentschler, Martin, Iglesias, Sirma, Schmid, Marie‐Ann, Liu, Cunming, Tschierlei, Stefanie, Frey, Wolfgang, Zhang, Xiaoyi, Karnahl, Michael, and Moonshiram, Dooshaye

Subjects
X-ray spectroscopy, TIME-dependent density functional theory, X-ray emission spectroscopy, PHOTOSENSITIZERS, LIGANDS (Chemistry), X-ray absorption
Abstract

A systematic series of four novel homo‐ and heteroleptic CuI photosensitizers based on tetradentate 1,10‐phenanthroline ligands of the type X^N^N^X containing two additional donor moieties in the 2,9‐position (X=SMe or OMe) were designed. Their solid‐state structures were assessed by X‐ray diffraction. Cyclic voltammetry, UV‐vis absorption, emission and X‐ray absorption spectroscopy were then used to determine their electrochemical, photophysical and structural features in solution. Following, time‐resolved X‐ray absorption spectroscopy in the picosecond time scale, coupled with time‐dependent density functional theory calculations, provided in‐depth information on the excited state electron configurations. For the first time, a significant shortening of the Cu−X distance and a change in the coordination mode to a pentacoordinated geometry is shown in the excited states of the two homoleptic complexes. These findings are important with respect to a precise understanding of the excited state structures and a further stabilization of this type of photosensitizers. [ABSTRACT FROM AUTHOR]

Published
2020
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42. Spectroscopic Characterisation of a Bio‐Inspired Ni‐Based Proton Reduction Catalyst Bearing a Pentadentate N2S3 Ligand with Improved Photocatalytic Activity.

Author

Gotico, Philipp, Moonshiram, Dooshaye, Liu, Cunming, Zhang, Xiaoyi, Guillot, Régis, Quaranta, Annamaria, Halime, Zakaria, Leibl, Winfried, and Aukauloo, Ally

Subjects
*ELECTRON donors, *X-ray absorption, *CATALYSTS, *PROTONS, *X-ray spectroscopy, *METAL nanoparticles, *NICKEL catalysts, *LIGHT absorption
Abstract

Inspired by the sulfur‐rich environment found in active hydrogenase enzymes, a Ni‐based proton reduction catalyst with pentadentate N2S3 ligand was synthesised. When coupled with [Ru(bpy)3]2+ (bpy=2,2′‐bipyridine) as photosensitiser and ascorbate as electron donor in a 1:1 mixture of dimethylacetamide and aqueous ascorbic acid/ascorbate buffer, the catalyst showed improved photocatalytic activity compared with a homologous counterpart bearing a tetradentate N2S2 ligand. The mechanistic pathway of photoinduced hydrogen evolution was comprehensively analysed through optical transient absorption and time‐resolved X‐ray absorption spectroscopy, which revealed important electronic and structural changes in the catalytic system during photoirradiation. The NiII catalyst undergoes a photoinduced metal‐centred reduction to form a NiI intermediate with distorted square‐bipyramidal geometry. Further kinetic analyses revealed differences in charge‐separation dynamics between the pentadentate and tetradentate forms. [ABSTRACT FROM AUTHOR]

Published
2020
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48. Structural and Spectroscopic Characterization of Reaction Intermediates Involved in a Dinuclear Co–Hbpp Water Oxidation Catalyst

Author

Gimbert-Suriñach, Carolina, primary, Moonshiram, Dooshaye, additional, Francàs, Laia, additional, Planas, Nora, additional, Bernales, Varinia, additional, Bozoglian, Fernando, additional, Guda, Alexander, additional, Mognon, Lorenzo, additional, López, Isidoro, additional, Hoque, Md Asmaul, additional, Gagliardi, Laura, additional, Cramer, Christopher J., additional, and Llobet, Antoni, additional

Published
2016
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49. A Million Turnover Molecular Anode for Catalytic Water Oxidation

Author

Creus, Jordi, primary, Matheu, Roc, additional, Peñafiel, Itziar, additional, Moonshiram, Dooshaye, additional, Blondeau, Pascal, additional, Benet-Buchholz, Jordi, additional, García-Antón, Jordi, additional, Sala, Xavier, additional, Godard, Cyril, additional, and Llobet, Antoni, additional

Published
2016
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