54 results on '"Antonio Francés-Monerris"'
Search Results
2. Spatial and Temporal Resolution of the Oxygen-Independent Photoinduced DNA Interstrand Cross-Linking by a Nitroimidazole Derivative
- Author
-
Antonio Francés-Monerris, Iñaki Tuñón, Abdelazim Abdelgawwad, and Antonio Monari
- Subjects
Oxygen ,Photosensitizing Agents ,Nitroimidazoles ,General Chemical Engineering ,DNA ,General Chemistry ,Library and Information Sciences ,Base Pairing ,Computer Science Applications - Abstract
DNA damage is ubiquitous in nature and is at the basis of emergent treatments such as photodynamic therapy, which is based on the activation of highly oxidative reactive oxygen species by photosensitizing O
- Published
- 2022
3. Oxidation-sensitive cysteines drive IL-38 amyloid formation
- Author
-
Alejandro Diaz-Barreiro, Gea Cereghetti, Jenna Tonacini, Dominique Talabot-Ayer, Sylvie Kieffer-Jaquinod, Arnaud Huard, Christopher Swale, Yohann Couté, Matthias Peter, Antonio Francés-Monerris, and Gaby Palmer
- Abstract
Cytokines of the interleukin (IL)-1 family are widely expressed in epithelial surfaces, including the epidermis, where they play a key role in the maintenance of barrier integrity and host defense. A recent report associated the IL-1 family member IL-33 with stress granules (SGs) in epithelial cells. Formation of SGs is promoted by the aggregation of proteins harboring low complexity regions (LCRs). In this study, using computational analyses, we predicted the presence of LCRs in six of the eleven IL-1 family members. Among these, IL-38 contained a long LCR and localized to Ras GTPase-activating protein binding protein 1 (G3BP1) positive SGs, as well as to G3BP1 negative intracellular protein condensates in keratinocytes exposed to oxidative stress (OS). In addition, we identified two highly aggregation-prone amyloid core (AC) motifs in the IL-38 LCR and detected the formation of amyloid IL-38 aggregates in response to OS in cells andin vitro. Disulfide bond mapping,in silicomodelling and the analysis of specific cysteine mutants supported a model in which specific oxidation-sensitive cysteines act as redox switches to modify the conformation of IL-38 and thus the surface exposure of its ACs, shuttling it from a soluble state into biomolecular condensates. Finally, the presence of IL-38 granules in human epidermal layers highly exposed to environmental OS suggests that oxidation-induced formation of amyloid aggregates, as a previously unrecognized intrinsic biological property of IL-38, may be physiologically relevant at this epithelial barrier.
- Published
- 2023
4. Contributors
- Author
-
Stefano Battaglia, Yi-Chun Chu, Stefano Corni, Juliana Cuéllar-Zuquin, Piotr de Silva, Leonardo Evaristo de Sousa, Adrian L. Dempwolff, Valentin Diez-Cabanes, Pavlo O. Dral, Andreas Dreuw, Simona Fantacci, Daniele Fazzi, Ignacio Fdez. Galván, Antonio Francés-Monerris, Jacopo Fregoni, Luis Manuel Frutos, Cristina García-Iriepa, Angelo Giussani, John M. Herbert, Alejandro Jodra, Waldemar Kaiser, M.G. Khrenova, Jingbai Li, Roland Lindh, Steven A. Lopez, Raúl Losantos, Zhao-Xue Luan, Marco Marazzi, Lara Martínez-Fernández, Edoardo Mosconi, Isabelle Navizet, Martina Nucci, Mariachiara Pastore, Daniel Roca-Sanjuán, Diego Sampedro, A.P. Savitsky, Javier Segarra-Martí, Morgane Vacher, Xin-Ping Wu, Ming-Yu Yang, Lin Zhao, and Zi-Jian Zhou
- Published
- 2023
5. DNA photostability
- Author
-
Lara Martínez-Fernández and Antonio Francés-Monerris
- Published
- 2023
6. Photochemistry of HOSO2 and SO3 and Implications for the Production of Sulfuric Acid
- Author
-
Joseph S. Francisco, Carlos A. Cuevas, Daniel Roca-Sanjuán, Tarek Trabelsi, Javier Carmona-García, Antonio Francés-Monerris, Alfonso Saiz-Lopez, Fundación Caixa Galicia, Ministerio de Ciencia e Innovación (España), Generalitat Valenciana, and Universidad de Valencia
- Subjects
Radical ,Photodissociation ,Context (language use) ,Sulfuric acid ,General Chemistry ,Photochemistry ,Biochemistry ,Catalysis ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,chemistry ,Sulfur trioxide ,Reactivity (chemistry) ,Acid rain ,Sulfur dioxide - Abstract
9 pags., 5 figs., Sulfur trioxide (SO3) and the hydroxysulfonyl radical (HOSO2) are two key intermediates in the production of sulfuric acid (H2SO4) on Earth's atmosphere, one of the major components of acid rain. Here, the photochemical properties of these species are determined by means of high-level quantum chemical methodologies, and the potential impact of their light-induced reactivity is assessed within the context of the conventional acid rain generation mechanism. Results reveal that the photodissociation of HOSO2 occurs primarily in the stratosphere through the ejection of hydroxyl radicals (•OH) and sulfur dioxide (SO2). This may decrease the production rate of H2SO4 in atmospheric regions with low O2 concentration. In contrast, the photostability of SO3 under stratospheric conditions suggests that its removal efficiency, still poorly understood, is key to assess the H2SO4 formation in the upper atmosphere., The project that gave rise to these results received the support of a fellowship for J.C.-G. from “la Caixa” Foundation (ID 100010434); the fellowship code is LCF/BQ/DR20/11790027. This work was supported by the Spanish “Ministerio de Ciencia e Innovación (MICINN)” (Project ref. CTQ2017-87054-C2-2-P) and Unit of Excellence María de Maeztu CEX2019-000919-M). D.R.-S. is grateful to the Spanish MICINN for the “Ramón y Cajal” grant (ref. RYC2015-19234). A.F.-M. is grateful to the Generalitat Valenciana and the European Social Fund for the postdoctoral contract APOSTD/2019/149 and the project GV/2020/226, and to the MICINN for the “Juan de la Cierva” contract IJC2019-039297-I. Computations have been partially conducted at the local QCEXVAL cluster and the Tirant v3 supercluster (Servei d’Informatica of the University of Valencia).
- Published
- 2021
7. Light‐Induced On/Off Switching of the Surfactant Character of the o ‐Cobaltabis(dicarbollide) Anion with No Covalent Bond Alteration
- Author
-
Francesc Teixidor, Clara Viñas, Antonio Francés-Monerris, Jewel Ann Maria Xavier, Abdelazim M. A. Abdelgawwad, Daniel Roca-Sanjuán, Generalitat Valenciana, Generalitat de Catalunya, Ministerio de Ciencia, Innovación y Universidades (España), European Commission, Xavier, Jewel Ann Maria [0000-0002-5925-5900], Roca-Sanjuán, Daniel [0000-0001-6495-2770], Viñas, Clara [0000-0001-5000-0277], Teixidor, Francesc [0000-0002-3010-2417], Francés Monerris, Antonio [0000-0001-8232-4989], Xavier, Jewel Ann Maria, Roca-Sanjuán, Daniel, Viñas, Clara, Teixidor, Francesc, and Francés Monerris, Antonio
- Subjects
Photodynamics ,Aqueous solution ,Chemistry ,General Medicine ,General Chemistry ,Photochemistry ,Fluorescence ,Quantum chemistry ,Micelle ,Catalysis ,Thermal decay ,Covalent bond ,Carborane ,Ground state ,Conformational isomerism - Abstract
Cobaltabis(dicarbollide) anion ([o-COSAN]- ) is a well-known metallacarborane with multiple applications in a variety of fields. In aqueous solution, the cisoid rotamer is the most stable disposition in the ground state. The present work provides theoretical evidence on the possibility to photoinduce the rotation from the cisoid to the transoid rotamer, a conversion that can be reverted when the ground state is repopulated. The non-radiative decay mechanisms proposed in this work are coherent with the lack of fluorescence observed in 3D fluorescence mapping experiments performed on [o-COSAN]- and its derivatives. This phenomenon induced by light has the potential to destruct the vesicles and micelles cisoid [o-COSAN]- typically forms in aqueous solution, which could lead to promising applications, particularly in the field of nanomedicine., This work was supported by the Generalitat Valenciana (GV, project GV/2020/226), Generalitat de Catalunya (2017 SGR 1720), and the Spanish Ministerio de Ciencia e Innovación (MICINN, projects CTQ2017-87054-C2-2–304-P and PID2019-106832RB-I00). A.M.A.A. is grateful to the Erasmus+ Programme of the European Comission for his Erasmus Mundus TCCM scholarship. A.F.-M. is grateful to the GV and the European Social Fund for the postdoctoral contract APOSTD/2019/149 and to the MICINN for the Juan de la Cierva contract IJC2019-039297-I. D.R.-S. is grateful to the MICINN for the “Ramón y Cajal” grant (RYC-2015–19234). “Severo Ochoa” Program for Centers of Excellence in R&D 234 (SEV-2015-0496) is appreciated. J. A. M. Xavier acknowledges DOC-FAM programme under the Marie Sklodowska-Curie grant agreement No. 754397 and is enrolled in the PhD program of the UAB. Computations have been conducted at the local QCEXVAL and the LluisVives and Tirant III clusters of the Servei d'Informàtica (University of Valencia). We thank Dr. Jordi Faraudo (ICMAB-CSIC) for the scientific discussions., With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).
- Published
- 2021
8. A multiscale free energy method reveals an unprecedented photoactivation of a bimetallic Os(II)-Pt(II) dual anticancer agent
- Author
-
Antonio Francés-Monerris and Marta Erminia Alberto
- Subjects
Photochemotherapy ,Coordination Complexes ,Photochemistry ,Transition Elements ,General Physics and Astronomy ,Antineoplastic Agents ,Physical and Theoretical Chemistry - Abstract
The photoreactivity of relatively large transition metal complexes is often limited to the description of the static potential energy surfaces of the involved electronic states. While useful to grasp some physical grounds of the photoinduced molecular responses, this approach does not statistically sample the multiple molecular degrees of freedom of the systems under investigation, which grow significantly if we consider the explicit coupling with the environment, and does not consider dynamic effects. The problem is even more complex if the reactivity takes place in the excited state. The present work uses state-of-the-art multiscale QM/MM dynamics to describe the photoactivation of a Pt(II)-unit of an
- Published
- 2022
9. Photochemistry and Non-adiabatic Photodynamics of the HOSO Radical
- Author
-
Joseph S. Francisco, Tarek Trabelsi, Antonio Francés-Monerris, Alfonso Saiz-Lopez, Daniel Roca-Sanjuán, Javier Carmona-García, Carlos A. Cuevas, Fundación Caixa Galicia, Generalitat Valenciana, Ministerio de Ciencia, Innovación y Universidades (España), and Universidad de Valencia
- Subjects
Ozone ,business.industry ,Chemistry ,General Chemistry ,Photochemistry ,Biochemistry ,Quantum chemistry ,Catalysis ,Atmosphere ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Reactivity (chemistry) ,Geoengineering ,business ,Adiabatic process ,Stratosphere - Abstract
6 pags., 2 figs., Hydroxysulfinyl radical (HOSO) is important due to its involvement in climate geoengineering upon SO2 injection and generation of the highly hygroscopic H2SO4. Its photochemical behavior in the upper atmosphere is, however, uncertain. Here we present the ultraviolet-visible photochemistry and photodynamics of this species by simulating the atmospheric conditions with high-level quantum chemistry methods. Photocleavage to HO + SO arises as the major solar-induced channel, with a minor contribution of H + SO2 photoproducts. The efficient generation of SO is relevant due to its reactivity with O3 and the consequent depletion of ozone in the stratosphere., The project that gave rise to these results received the support of a fellowship for J.C.-G. from “La Caixa” Foundation (ID 100010434); the fellowship code is LCF/BQ/DR20/ 11790027. A.F.-M. is grateful to the Generalitat Valenciana and the European Social Fund for the postdoctoral contract APOSTD/2019/149 and the project GV/2020/226. This work was supported by the Spanish “Ministerio de Ciencia e Innovación (MICINN)” (Project ref CTQ2017-87054-C2-2-P and Unit of Excellence María de Maeztu CEX2019-000919- M). D.R.-S. is grateful to the Spanish MICINN for the “Ramón y Cajal” grant (ref RYC-2015-19234). Computations have been partially conducted at the local QCEXVAL cluster and the Tirant v3 supercluster (University of Valencia).
- Published
- 2021
10. Photochemical and thermochemical pathways to S2 and polysulfur formation in the atmosphere of Venus
- Author
-
Antonio Francés-Monerris, Javier Carmona-García, Tarek Trabelsi, Alfonso Saiz-Lopez, James R. Lyons, Joseph S. Francisco, Daniel Roca-Sanjuán, Universidad de Valencia, Université de Lorraine (France), Generalitat Valenciana, Ministerio de Ciencia e Innovación (España), and Fundación 'la Caixa'
- Subjects
Multidisciplinary ,General Physics and Astronomy ,General Chemistry ,General Biochemistry, Genetics and Molecular Biology - Abstract
8 pags., 3 figs., Polysulfur species have been proposed to be the unknown near-UV absorber in the atmosphere of Venus. Recent work argues that photolysis of one of the (SO) isomers, cis-OSSO, directly yields S with a branching ratio of about 10%. If correct, this pathway dominates polysulfur formation by several orders of magnitude, and by addition reactions yields significant quantities of S, S, and S. We report here the results of high-level ab-initio quantum-chemistry computations that demonstrate that S is not a product in cis-OSSO photolysis. Instead, we establish a novel mechanism in which S is formed in a two-step process. Firstly, the intermediate SO is produced by the coupling between the S and Cl atmospheric chemistries (in particular, SO reaction with ClS) and in a lesser extension by O-abstraction reactions from cis-OSSO. Secondly, SO reacts with SO. This modified chemistry yields S and subsequent polysulfur abundances comparable to the photolytic cis-OSSO mechanism through a more plausible pathway. Ab initio quantification of the photodissociations at play fills a critical data void in current atmospheric models of Venus., Calculations have been partially conducted at the local QCEXVAL cluster and the Lluis Vives v2 and Tirant v3 superclusters of the Servei d’Informàtica (University of Valencia), and at the local LPCT cluster and the regional ExpLor center (University of Lorraine, France). A.F.-M. thanks Generalitat Valenciana and the European Social Fund for the post-doctoral contract APOSTD/2019/149 and the project GV/2020/226, and the Ministerio de Ciencia e Innovación (MICINN) for the Juan de la Cierva contract IJC2019-039297-I. D.R.-S. is grateful to the MICINN for the project CTQ2017-87054-C2-2-P and the Ramón y Cajal grant RYC2015- 19234. The project that gave rise to these results received also the support of a fellowship for J.C.-G. from “la Caixa” Foundation (ID 100010434); the fellowship code is LCF/BQ/DR20/11790027.
- Published
- 2022
11. Photochemical and thermochemical pathways to S
- Author
-
Antonio, Francés-Monerris, Javier, Carmona-García, Tarek, Trabelsi, Alfonso, Saiz-Lopez, James R, Lyons, Joseph S, Francisco, and Daniel, Roca-Sanjuán
- Abstract
Polysulfur species have been proposed to be the unknown near-UV absorber in the atmosphere of Venus. Recent work argues that photolysis of one of the (SO)
- Published
- 2022
12. Trans-to-cis photoisomerization of cyclocurcumin in different environments rationalized by computational photochemistry
- Author
-
Maxime Mourer, Marco Marazzi, Antonio Francés-Monerris, Andreea Pasc, Antonio Monari, University of Alcalá / Department of Analytical Chemistry, Physical-Chemistry and Chemical Engineering, Universidad de Alcalá - University of Alcalá (UAH), Laboratoire de Physique et Chimie Théoriques (LPCT), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Facultat de Fisica [València] (UV), Universitat de València (UV), and Laboratoire Lorrain de Chimie Moléculaire (L2CM)
- Subjects
Photoswitch ,Photoisomerization ,Chemistry ,General Physics and Astronomy ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Fluorescence ,0104 chemical sciences ,Excited state ,[CHIM]Chemical Sciences ,Molecule ,Physical and Theoretical Chemistry ,Solvent effects ,0210 nano-technology ,Ground state ,Cis–trans isomerism - Abstract
International audience; Cyclocurcumin is a turmeric component that attracted much less attention compared to the well known curcumin. In spite of the less deep charcaterization of its properties, cyclocurcumin has shown promising anticancer effects when used in combination with curcumin. Especially, due to its peculiar molecular structure, cyclocurcumin can be regarded as an almost ideal photoswitch, whose capabilities can also be exploited for relevant biological applications. Here, by means of state-of-the-art computational methods for electronic excited-state calculations (TD-DFT, MS-CASPT2, XMS-CASPT2) we analyze in detail the absorption and photoisomerization pathways leading from the more stable trans isomer to the cis one. The different molecular surroundings, taken into account by means of electrostatic solvent effect and compared with available experimental data, have been found to be critical in describing the fate of irradiated cyclocurcumin: while in non-polar environments an excited state barrier prevents photoisomerization and favours fluorescence, in polar solvents an almost barrierless path results in a strikingly decrease of fluorescence, opening the way toward a crossing region with the ground state and thus funneling the photoproduction of the cis isomer.
- Published
- 2020
13. Quantum chemistry of the excited state: advances in 2020–2021
- Author
-
Juliana Cuéllar-Zuquin, Javier Carmona-García, Miriam Navarrete-Miguel, Luis Cerdán, Antonio Francés-Monerris, Angelo Giussani, Javier Segarra-Martí, and Daniel Roca-Sanjuán
- Published
- 2022
14. Triplet stabilization for enhanced drug photorelease from sunscreen-based photocages
- Author
-
Antonio Monari, Virginie Lhiaubet-Vallet, Mauricio Lineros-Rosa, M. Consuelo Cuquerella, Antonio Francés-Monerris, Miguel A. Miranda, Ministerio de Ciencia e Innovación (España), and Generalitat Valenciana
- Subjects
Drug ,Ultraviolet Rays ,media_common.quotation_subject ,UV filter ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Biochemistry ,chemistry.chemical_compound ,QUIMICA ORGANICA ,Hexanes ,Prodrugs ,Physical and Theoretical Chemistry ,media_common ,Propiophenones ,Quenching (fluorescence) ,Photolysis ,Photosensitizing Agents ,Ethanol ,010405 organic chemistry ,Organic Chemistry ,Anti-Inflammatory Agents, Non-Steroidal ,Acceptor ,0104 chemical sciences ,Hexane ,Solvent ,chemistry ,Models, Chemical ,Ketoprofen ,Excited state ,Solvents ,Avobenzone ,Sunscreening Agents - Abstract
[EN] Recently, sunscreen-based drug photocages have been introduced to provide UV protection to photoactive drugs, thus increasing their photosafety. Here, combined experimental and theoretical studies performed on a photocage based on the commercial UVA filter avobenzone (AB) and on the photosensitizing non-steroidal anti-inflammatory drug ketoprofen (KP) are presented unveiling the photophysical processes responsible for the light-triggered release. Particular attention is paid to solvent stabilization of the drug and UV filter excited states, respectively, which leads to a switching between the triplet excited state energies of the AB and KP units. Most notably, we show that the stabilization of the AB triplet excited state in ethanol solution is the key requirement for an efficient photouncaging. By contrast, in apolar solvents, in particular hexane, KP has the lowest triplet excited state, hence acting as an energy acceptor quenching the AB triplet manifold, thus inhibiting the desired photoreaction., Support from the Universite de Lorraine, CNRS, regional (Prometeo/2017/075) and Spanish Government (PGC2018-096684-B-I00, CTQ2017-87054-C2-2-P) is kindly acknowledged. A. F.-M. is grateful to Generalitat Valenciana and the European Social Fund (postdoctoral contract APOSTD/2019/149 and project GV/2020/226) for financial support. M. L.-R. acknowledges the Universitat Politecnica de Valencia for the FPI grant. All calculations have been performed on the local LPCT computer center and on the Explor regional center in the framework of the project "Dancing under the light".
- Published
- 2021
15. Photochemistry of HOSO
- Author
-
Javier, Carmona-García, Tarek, Trabelsi, Antonio, Francés-Monerris, Carlos A, Cuevas, Alfonso, Saiz-Lopez, Daniel, Roca-Sanjuán, and Joseph S, Francisco
- Abstract
Sulfur trioxide (SO
- Published
- 2021
16. Hypoxia-Selective Dissociation Mechanism of a Nitroimidazole Nucleoside in a DNA Environment
- Author
-
Antonio Francés-Monerris, Iñaki Tuñón, Antonio Monari, Laboratoire de Physique et Chimie Théoriques (LPCT), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Departament de QuÍmica Física, and Universitat de València (UV)
- Subjects
Substituent ,Molecular Dynamics Simulation ,010402 general chemistry ,01 natural sciences ,chemistry.chemical_compound ,Molecular dynamics ,[CHIM]Chemical Sciences ,General Materials Science ,Photosensitizer ,A-DNA ,Physical and Theoretical Chemistry ,ComputingMilieux_MISCELLANEOUS ,Photosensitizing Agents ,Nitroimidazole ,010405 organic chemistry ,Hydrogen bond ,Hydrogen Bonding ,DNA ,0104 chemical sciences ,Thymine ,chemistry ,Nitroimidazoles ,Biophysics ,Nucleic Acid Conformation ,Quantum Theory - Abstract
Photodynamic therapy is a promising approach to treat a variety of superficial tumors and other diseases. One of its major limitations arises from its dependence on molecular oxygen, which decreases the efficiency of the therapy in hypoxia conditions commonly developed by solid tumors. The present contribution reveals the molecular mechanism of a modified thymine bearing a nitroimidazole substituent, a photosensitizer able to produce highly harmful interstrand cross-links in the DNA double strand after irradiation selectively in absence of oxygen. The mechanism is resolved at a fully atomistic and electronic level relying on quantum mechanics (CASPT2, coupled-cluster, DFT, and TD-DFT methods), classical molecular dynamics, and advanced biased QM/MM simulations, revealing an energy penalty of ∼8 kcal/mol for the anionic nitromidazole release. Our findings indicate that the global interstrand cross-link production is driven by a combination of multiple factors, namely, the reverse energy penalty, the diffusion of the nitroimidazole anion, and the further reactivity of the formed thymine radical. On the basis of these results, we also suggest some possible strategies to improve the efficiency of interstrand cross-link production.
- Published
- 2019
17. Effect of Iodination on the Photophysics of the Laser Borane anti-B18H22: Generation of Efficient Photosensitizers of Oxygen
- Author
-
Lenka Slusna, Daniel Roca-Sanjuán, Jiří Dolanský, Antonio Francés-Monerris, Jonathan Bould, Kaplan Kirakci, Pavel Kubát, Dusan Lorenc, Ivana Císařová, Eva Noskovicova, Kamil Lang, Michael G. S. Londesborough, and Jakub Braborec
- Subjects
010405 organic chemistry ,Singlet oxygen ,Nuclear magnetic resonance spectroscopy ,Borane ,010402 general chemistry ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Yield (chemistry) ,Physical and Theoretical Chemistry ,Spectroscopy ,Phosphorescence ,Derivative (chemistry) ,Dichloromethane - Abstract
Treatment of the laser borane anti-B18H22 (compound 1) with iodine in ethanol gives the monoiodinated derivative 7-I-anti-B18H21 (compound 2) in 67% yield, or, by reaction with iodine or ICl in the presence of AlCl3 in dichloromethane, the diiodinated derivative 4,4'-I2-anti-B18H20 (compound 3) in 85% yield. On excitation with 360 nm light, both compounds 2 and 3 give strong green phosphorescent emissions (λmax = 525 nm, ΦL = 0.41 and λmax = 545 nm, ΦL = 0.71 respectively) that are quenched by dioxygen to produce O2(1Δg) singlet oxygen with quantum yields of ΦΔ = 0.52 and 0.36 respectively. Similarly strong emissions can be stimulated via the nonlinear process of two-photon absorption when exciting with 720 or 800 nm light. The high quantum yields of singlet-oxygen production, coupled with the option of two-photon excitation, make compounds 2 and 3 promising O2(1Δg) photosensitizers. The molecular structures of compounds 2 and 3 were determined by single-crystal X-ray crystallographic studies as well as multinuclear NMR spectroscopy and mass spectrometry. Time-resolved UV-vis spectroscopy was used to delineate their photophysical properties, and the electronic-structure properties of the emitting species were determined by means of multiconfigurational quantum-chemistry computations.
- Published
- 2019
18. Hydroxyl Radical Addition to Thymine and Cytosine and Photochemistry of the Adducts at the C6 Position
- Author
-
Daniel Roca-Sanjuán, Antonio Francés-Monerris, and Vicent J. Borràs
- Subjects
chemistry.chemical_compound ,chemistry ,Radical ,Organic Chemistry ,Hydroxyl radical ,Physical and Theoretical Chemistry ,Photochemistry ,Cytosine ,Analytical Chemistry ,Adduct ,Thymine - Published
- 2019
19. Toward Luminescent Iron Complexes: Unravelling the Photophysics by Computing Potential Energy Surfaces
- Author
-
Antonio Monari, Mariachiara Pastore, Philippe C. Gros, Antonio Francés-Monerris, Xavier Assfeld, Laboratoire de Physique et Chimie Théoriques (LPCT), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Lorrain de Chimie Moléculaire (L2CM), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)
- Subjects
Materials science ,010304 chemical physics ,Organic Chemistry ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Potential energy ,0104 chemical sciences ,Analytical Chemistry ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Excited state ,0103 physical sciences ,Physical and Theoretical Chemistry ,Luminescence ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience
- Published
- 2019
20. A theoretical analysis of the structure and properties of B26H30 isomers. Consequences to the laser and semiconductor doping capabilities of large borane clusters
- Author
-
Antonio Francés-Monerris, Drahommír Hnyk, Jan Macháček, Michael G. S. Londesborough, Eluvathingal D. Jemmis, Jindřich Fanfrlík, Daniel Roca-Sanjuán, and Naiwrit Karmodak
- Subjects
Materials science ,business.industry ,Doping ,Cluster chemistry ,General Physics and Astronomy ,02 engineering and technology ,Borane ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Semiconductor ,chemistry ,Chemical physics ,Decaborane ,Structural isomer ,Molecule ,Density functional theory ,Physical and Theoretical Chemistry ,0210 nano-technology ,business - Abstract
Decaborane(14), nido-B10H14, is the major commercially available molecular building block in boron cluster chemistry. The condensation of two such {nido-B10} blocks gives the known isomers of B18H22 – a molecule used in the fabrication of p-type semiconductors and capable of blue laser emission. Here, we computationally determine the structures and thermodynamic stabilities of 20 possible B26H30 regioisomers constructed from the fusion of three {nido-B10} blocks with the three subclusters conjoined by two-boron atom shared edges. In addition, density functional theory, time-dependent (TD)-DFT and multiconfigurational CASPT2 methods have been used to model and investigate the physical and photophysical properties of the three most stable of these isomers. Our findings predict these isomers to be potentially useful materials for the semiconductor industry, as high boron-content doping agents, and in the fabrication of new optical materials.
- Published
- 2019
21. Photochemistry of oxidized Hg(I) and Hg(II) species suggests missing mercury oxidation in the troposphere
- Author
-
Alfonso Saiz-Lopez, Martin Jiskra, Joseph S. Francisco, Daniel Roca-Sanjuán, John M. C. Plane, Daniel J. Jacob, Jeroen E. Sonke, Johannes Bieser, Feiyue Wang, Antonio Francés-Monerris, Colin P. Thackray, Javier Carmona-García, Juan Z. Dávalos, A. Ulises Acuña, Carlos A. Cuevas, Oleg Travnikov, Instituto de Química Física Rocasolano (IQFR), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), European Commission, Ministerio de Economía y Competitividad (España), Consejo Superior de Investigaciones Científicas (España), Generalitat Valenciana, Universidad de Valencia, Swiss National Science Foundation, Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
- Subjects
atmospheric chemistry ,Atmospheric chemistry ,010504 meteorology & atmospheric sciences ,Tropospheric chemistry ,Mercury photoreduction ,chemistry.chemical_element ,atmospheric modeling ,Atmospheric model ,010501 environmental sciences ,Photochemistry ,01 natural sciences ,Troposphere ,Mercury oxidation ,Computer Simulation ,Gas-phase mercury reactivity ,gas-phase mercury reactivity ,0105 earth and related environmental sciences ,mercury photoreduction ,Thermal oxidation ,Multidisciplinary ,Atmosphere ,Photodissociation ,Correction ,Mercury ,Models, Theoretical ,Photochemical Processes ,tropospheric chemistry ,Mercury (element) ,Atmospheric modeling ,Deposition (aerosol physics) ,chemistry ,13. Climate action ,[CHIM.OTHE]Chemical Sciences/Other ,Oxidation-Reduction - Abstract
8 pags., 5 figs., 2 tabs., Mercury (Hg), a global contaminant, is emitted mainly in its elemental form Hgto the atmosphere where it is oxidized to reactive Hgcompounds, which efficiently deposit to surface ecosystems. Therefore, the chemical cycling between the elemental and oxidized Hg forms in the atmosphere determines the scale and geographical pattern of global Hg deposition. Recent advances in the photochemistry of gas-phase oxidized Hgand Hgspecies postulate their photodissociation back to Hgas a crucial step in the atmospheric Hg redox cycle. However, the significance of these photodissociation mechanisms on atmospheric Hg chemistry, lifetime, and surface deposition remains uncertain. Here we implement a comprehensive and quantitative mechanism of the photochemical and thermal atmospheric reactions between Hg, Hg, and Hgspecies in a global model and evaluate the results against atmospheric Hg observations. We find that the photochemistry of Hgand Hgleads to insufficient Hg oxidation globally. The combined efficient photoreduction of Hgand Hgto Hgcompetes with thermal oxidation of Hg, resulting in a large model overestimation of 99% of measured Hgand underestimation of 51% of oxidized Hg and ∼66% of Hgwet deposition. This in turn leads to a significant increase in the calculated global atmospheric Hg lifetime of 20 mo, which is unrealistically longer than the 3-6-mo range based on observed atmospheric Hg variability. These results show that the Hgand Hgphotoreduction processes largely offset the efficiency of bromine-initiated Hgoxidation and reveal missing Hg oxidation processes in the troposphere., This study has received funding from the European Research Council Executive Agency under the European Union’s Horizon 2020 Research and Innovation programme (Project ERC-2016- COG 726349 CLIMAHAL) and the Spanish Ministerio de Economía y Competitividad (MINECO) /Fondo Europeo de Desarrollo Regional (FEDER) (Projects CTQ2017-87054-C2-2-P, RYC-2015-19234, and CEX2019-000919-M). This work was supported by the Consejo Superior de Investigaciones Científicas (CSIC) Spain. A.F.-M. acknowledges the Generalitat Valenciana and the European Social Fund (Contract APOSTD/2019/149 and Project GV/2020/ 226) for the financial support. J.C.-G. acknowledges the Universitat de València for his Masters Scholarship. M.J. acknowledges funding by the Swiss National Science Foundation (Grant PZ00P2_174101). The ETMEP measurements as well as ground-based measurements of the GMOS network were funded by the EU FP7-ENV-2010 project (GMOS, Grant Agreement 265113). J.S.F. acknowledges the H2020 ERA-PLANET (689443) Integrated Global Observing Systems for Persistent Pollutants (iGOSP) and Integrative and Comprehensive Understanding on Polar Environments (iCUPE) programs
- Published
- 2020
22. Experimental and theoretical studies on thymine photodimerization mediated by oxidatively generated DNA lesions and epigenetic intermediates
- Author
-
Antonio Monari, Miguel A. Miranda, Virginie Lhiaubet-Vallet, Mauricio Lineros-Rosa, Antonio Francés-Monerris, Ministerio de Economía y Competitividad (España), and Ministerio de Ciencia, Innovación y Universidades (España)
- Subjects
DNA damage ,Photochemistry ,Ultraviolet Rays ,Bases ,General Physics and Astronomy ,Pyrimidine dimer ,010402 general chemistry ,01 natural sciences ,Nucleobase ,Epigenesis, Genetic ,chemistry.chemical_compound ,Triplet energy-transfer ,Cytosine ,QUIMICA ORGANICA ,Molecule ,Epigenetics ,Physical and Theoretical Chemistry ,Uracil ,010405 organic chemistry ,Dimer formation ,0104 chemical sciences ,Thymine ,Dynamics ,Damage ,Photophysics ,chemistry ,Biophysics ,Nucleic acid ,Sunlight ,Mechanism ,Photosensitization ,Dimerization ,Oxidation-Reduction ,DNA ,DNA Damage - Abstract
[EN] Interaction of nucleic acids with light is a scientific question of paramount relevance not only in the understanding of life functioning and evolution, but also in the insurgence of diseases such as malignant skin cancer and in the development of biomarkers and novel light-assisted therapeutic tools. This work shows that the UVA portion of sunlight, not absorbed by canonical DNA nucleobases, can be absorbed by 5-formyluracil (ForU) and 5-formylcytosine (ForC), two ubiquitous oxidatively generated lesions and epigenetic intermediates present in living beings in natural conditions. We measure the strong propensity of these molecules to populate triplet excited states able to transfer the excitation energy to thymine-thymine dyads, inducing the formation of cyclobutane pyrimidine dimers (CPDs). By using steady-state and transient absorption spectroscopy, NMR, HPLC, and theoretical calculations, we quantify the differences in the triplet-triplet energy transfer mediated by ForU and ForC, revealing that the former is much more efficient in delivering the excitation energy and producing the CPD photoproduct. Although significantly slower than ForU, ForC is also able to harm DNA nucleobases and therefore this process has to be taken into account as a viable photosensitization mechanism. The present findings evidence a rich photochemistry crucial to understand DNA damage photobehavior., Support from the Universite de Lorraine, CNRS, regional (Prometeo/2017/075) and Spanish Government (PGC2018-096684-B-I00, CTQ2017-87054-C2-2-P) is kindly acknowledged. A. F.-M. is grateful to Generalitat Valenciana and the European Social Fund (postdoctoral contract APOSTD/2019/149 and project GV/2020/226) for financial support. M. L.-R. acknowledges the Universitat Politecnica de Valencia for the FPI grant. All calculations have been performed on the local LPCT computer center and on the Explor regional center in the framework of the project "Dancing under the light".
- Published
- 2020
23. DNA Photodamage and Repair: Computational Photobiology in Action
- Author
-
Antonio Monari, Antonio Francés-Monerris, Elise Dumont, Natacha Gillet, Laboratoire de Physique et Chimie Théoriques (LPCT), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Universitat de València (UV), Laboratoire de Chimie - UMR5182 (LC), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC)
- Subjects
Genome instability ,0303 health sciences ,Computer science ,DNA repair ,food and beverages ,Computational biology ,010402 general chemistry ,medicine.disease_cause ,01 natural sciences ,Multiscale modeling ,0104 chemical sciences ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,03 medical and health sciences ,chemistry.chemical_compound ,Photobiology ,chemistry ,medicine ,Metabolic Stress ,Carcinogenesis ,ComputingMilieux_MISCELLANEOUS ,DNA ,030304 developmental biology - Abstract
DNA is constantly exposed to external and metabolic stress agents, including the solar radiation and in particular the UV portion of the electromagnetic spectrum. Such source of stress can induce photochemical modification of the structure of DNA and of its basic components, i.e. the nucleobases. DNA lesions may ultimately lead to genomic instability, mutations, and even to carcinogenesis. Hence, cells dispose of complex biochemical repair pathways in charge of remove the DNA lesions and avoid their accumulation. In this Chapter, we present the complexity of the DNA lesion chemical and structural space, also complicated by the intricate coupling with the biological relevant signaling pathways. Through some relevant examples, we will show how proper multiscale simulation protocols can provide a unified picture of the complex phenomena and hence answer biological relevant questions, paving the way to a veritable computational photobiology approach.
- Published
- 2020
24. Thermodynamics of the interaction between the spike protein of severe acute respiratory syndrome- coronavirus-2 and the receptor of human angiotensin converting enzyme 2. Effects of possible ligands
- Author
-
Giampaolo Barone, Cécilia Hognon, Marco Marazzi, Tom Miclot, Cristina García-Iriepa, Antonio Francés-Monerris, Antonio Monari, and Isabel Iriepa
- Subjects
chemistry.chemical_classification ,Enzyme ,chemistry ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Angiotensin-converting enzyme 2 ,medicine ,Spike Protein ,Computational biology ,medicine.disease_cause ,Receptor ,Transmembrane protein ,Coronavirus ,Protein–protein interaction - Abstract
Since the end of 2019, the coronavirus SARS-CoV-2 has caused more than 180,000 deaths all over the world, still lacking a medical treatment despite the concerns of the whole scientific community. Human Angiotensin-Converting Enzyme 2 (ACE2) was recently recognized as the transmembrane protein serving as SARS-CoV-2 entry point into cells, thus constituting the first biomolecular event leading to COVID-19 disease. Here, by means of a state-of-the-art computational approach, we propose a rational evaluation of the molecular mechanisms behind the formation of the complex and of the effects of possible ligands. Moreover, binding free energy between ACE2 and the active Receptor Binding Domain (RBD) of the SARS-CoV-2 spike protein is evaluated quantitatively, assessing the molecular mechanisms at the basis of the recognition and the ligand-induced decreased affinity. These results boost the knowledge on the molecular grounds of the SARS-CoV-2 infection and allow to suggest rationales useful for the subsequent rational molecular design to treat severe COVID-19 cases.
- Published
- 2020
25. Thermodynamics of the interaction between the spike protein of severe acute respiratory syndrome- coronavirus-2 and the receptor of human angiotensin converting enzyme 2. Effects of possible ligands
- Author
-
Marco Marazzi, Antonio Monari, Giampaolo Barone, Tom Miclot, Isabel Iriepa, Antonio Francés-Monerris, Cecilia Hognon, and Cristina Garcia-Iriepa
- Abstract
Since the end of 2019, the coronavirus SARS-CoV-2 has caused more than 180,000 deaths all over the world, still lacking a medical treatment despite the concerns of the whole scientific community. Human Angiotensin-Converting Enzyme 2 (ACE2) was recently recognized as the transmembrane protein serving as SARS-CoV-2 entry point into cells, thus constituting the first biomolecular event leading to COVID-19 disease. Here, by means of a state-of-the-art computational approach, we propose a rational evaluation of the molecular mechanisms behind the formation of the complex and of the effects of possible ligands. Moreover, binding free energy between ACE2 and the active Receptor Binding Domain (RBD) of the SARS-CoV-2 spike protein is evaluated quantitatively, assessing the molecular mechanisms at the basis of the recognition and the ligand-induced decreased affinity. These results boost the knowledge on the molecular grounds of the SARS-CoV-2 infection and allow to suggest rationales useful for the subsequent rational molecular design to treat severe COVID-19 cases.
- Published
- 2020
26. Thymine Dimerization Induced by Oxidative DNA Lesions and Epigenetic Intermediates via Triplet-Triplet Energy Transfer
- Author
-
Virginie Lhiaubet-Vallet, Mauricio Lineros-Rosa, Antonio Francés-Monerris, Antonio Monari, and Miguel A. Miranda
- Subjects
chemistry.chemical_compound ,chemistry ,DNA damage ,Nucleic acid ,Biophysics ,Pyrimidine dimer ,Epigenetics ,DNA oxidation ,DNA ,Thymine ,Nucleobase - Abstract
Interaction of nucleic acids with light is a scientific question of paramount relevance not only in the understanding of life functioning and evolution, but also in the insurgence of diseases such as malignant skin cancer and in the development of biomarkers and novel light-assisted therapeutic tools. This work shows that the UVA portion of sunlight, not absorbed by canonical DNA nucleobases, can be absorbed by 5-formyluracil (ForU) and 5-formylcytosine (ForC), two ubiquitous oxidative lesions and epigenetic intermediates present in living beings in natural conditions. We measure the strong propensity of these molecules to populate triplet excited states able to transfer the excitation energy to thymine-thymine dyads, inducing the formation of the highly toxic and mutagenic cyclobutane pyrimidine dimers (CPDs). By using steady-state and transient absorption spectroscopy, NMR, HPLC, and theoretical calculations, we quantify the differences in the triplet-triplet energy transfer mediated by ForU and ForC, revealing that the former is much more efficient in delivering the excitation energy and producing the CPD photoproduct. Although significantly slower than ForU, ForC is also able to harm DNA nucleobases and therefore this process has to be taken into account as a viable photosensitization mechanism. The present findings evidence a rich photochemistry crucial to understand DNA photodamage and of potential use in the development of biomarkers and non-conventional photodynamic therapy agents.
- Published
- 2020
27. Has Ivermectin Virus-Directed Effects against SARS-CoV-2? Rationalizing the Action of a Potential Multitarget Antiviral Agent
- Author
-
Antonio Monari, Tom Miclot, Cécilia Hognon, Cristina García-Iriepa, Antonio Francés-Monerris, Isabel Iriepa, Marco Marazzi, and Giampaolo Barone
- Subjects
Proteases ,Immune system ,Ivermectin ,Viral replication ,Viral protein ,medicine ,Biology ,medicine.disease_cause ,Approved drug ,Virology ,Virus ,Coronavirus ,medicine.drug - Abstract
The novel SARS-CoV-2 coronavirus is causing a devastating pandemic in 2020, threatening public health in many countries. An unprecedented rapid and global response has been set in motion to identify efficient antiviral agents against SARS-CoV-2, mostly relying on the repurposing of drugs presenting or not previously known antiviral activity. Ivermectin is an approved drug used as antiparasitic in humans and animals with well documented broad-spectrum antiviral properties that emerge from host-directed effects. Recent results reported by Wagstaff and coworkers (Antiviral Research 2020, 178, 104787) show a potent inhibition of SARS-CoV-2 replication in vitro by ivermectin, and clinical trials with human volunteers have already started. However, the mode of action of ivermectin is still largely unknown, especially at the molecular level. Here, we employ advanced molecular dynamics simulations to assess the influence of ivermectin on several key viral protein targets, with the aim to reveal the molecular bases of antiviral mechanisms against SARS-CoV-2. Interestingly, we show that ivermectin could be regarded as a multitarget agent, inhibiting different viral functions. These include blocking the recognition by the SARS-CoV-2 Receptor Binding Domain (RBD) of the Angiotensin-Converting Enzyme 2 (ACE2), the interactions with the two viral proteases 3CLpro and PLpro, and the SARS Unique Domain (SUD) non-structural protein. Hence, the wide spectrum of actions involving i) the interference with cell infection, ii) the inhibition of viral replication, and iii) elusion of the host immune system, could point to an unprecedented synergy between host- and virus-directed effects explaining the high anti-SARS-CoV-2 activity observed for this compound.
- Published
- 2020
28. Unveiling the role of upper excited electronic states in the photochemistry and laser performance of: anti -B18H22
- Author
-
Jiří Dolanský, Michael G. S. Londesborough, Marcel Fuciman, Antonio Francés-Monerris, Daniel Roca-Sanjuán, Luis Cerdán, Jonathan Bould, Czech Science Foundation, Ministerio de Economía y Competitividad (España), Generalitat Valenciana, and Ministerio de Ciencia, Innovación y Universidades (España)
- Subjects
Blue laser ,education.field_of_study ,Materials science ,Population ,General Chemistry ,Borane ,Laser ,Photochemistry ,Quantum chemistry ,law.invention ,chemistry.chemical_compound ,chemistry ,Atomic orbital ,law ,Excited state ,Materials Chemistry ,Spectroscopy ,education - Abstract
13 pags., 7 figs., -- This article is part of the themed collection: Journal of Materials Chemistry C HOT Papers, In the search for innovative new light sources, the discovery that solutions of the boron hydride anti-B18H22 generate photostable blue laser emission stands out in its significance as the first laser borane. Surprisingly, though, the laser performance of anti-B18H22 (∼10% efficiency) does not match the expectations based on its exceptional photophysical properties (Φf = 0.97 and high photostability). To understand this contradiction, we herein present an investigation into the upper excited states of the anti-B18H22 photophysical system, which we suggest to be the most relevant factor to its laser performance. The use of computational quantum chemistry, laser and UV-vis spectroscopy, NMR spectroscopy, and mass spectrometry unveil the role of the upper excited states on the laser performance of anti-B18H22, showing that efficient excited state absorption (ESA) leads to the population of these states, and results not only in the loss of laser efficiency, but also in the activation of chemically reactive relaxation pathways and the formation of photochemically produced novel molecular species. The likely composition of these photoproducts, formed upon prolonged high intensity laser irradiation, is inferred from their molecular masses, NMR properties, and calculated natural orbitals. Together, these results are of key importance to the complete understanding of the anti-B18H22 photophysical system and provide valuable information to chemists and laser physicists working to mitigate deficiencies and enhance the performance of the next generation of borane lasers and borane-based photoactive materials., This work has been supported by the Czech Science Foundation (project No. 18-20286S). L. C. acknowledges financial support from the Spanish Ministerio de Economı´a y Competitividad (MINECO) through Grant number MAT2017-83856-C3-1. A. F.-M. is grateful to Generalitat Valenciana and the European Social Fund for a postdoctoral contract (APOSTD/2019/149). D. R.-S. is thankful to the Spanish MINECO/FEDER for financial support through the Ramon y Cajal fellowship (RYC-2015-19234) and the Unit of Excellence Maria de Maeztu (MDM-2015-0538). Support from the project CTQ2017-87054-C2-2-P (Ministerio de Ciencia e Innovacion) is gratefully acknowledged.
- Published
- 2020
29. Photoinduced DNA Lesions in Dormant Bacteria. The Peculiar Route Leading to Spore Photoproduct Unraveled by Multiscale Molecular Dynamics
- Author
-
Thierry Douki, Cécilia Hognon, Antonio Francés-Monerris, and Antonio Monari
- Subjects
biology ,DNA repair ,Chemistry ,DNA damage ,fungi ,Pyrimidine dimer ,biology.organism_classification ,Spore ,chemistry.chemical_compound ,Molecular dynamics ,Nucleic acid ,Biophysics ,Bacteria ,DNA - Abstract
Some bacterial species enter a dormant state in the form of spores to resist to unfavorable external conditions. Spores are resistant to a wide series of stress agents, including UV radiation, and can last for tens to hundreds of years. Due to the suspension of biological functions such as DNA repair, they accumulate DNA damage upon exposure to UV radiation. Differently from active organisms, the most common DNA photoproduct in spores are not cyclobutane pyrimidine dimers, but rather the so-called spore photoproduct. This non-canonical photochemistry results from the dry state of DNA and the binding to small acid soluble proteins that drastically modify the structure and photoreactivity of the nucleic acid. In this contribution, we use multiscale molecular dynamics simulations including extended classical molecular dynamics and QM/MM biased dynamics to elucidate the coupling of electronic and structural factors leading to this photochemical outcome. In particular, we rationalize the well-described impact of the peculiar DNA environment found in spores on the favored formation of the spore photoproduct, given the small free energy barrier found for this path. Meanwhile, the specific organization of spore DNA precludes the photochemical path leading to cyclobutane pyrimidine dimers formation.TOC GRAPHICS
- Published
- 2020
30. Thermodynamics of the Interaction Between SARS-CoV-2 Spike Protein and Human ACE2 Receptor. Effects of Possible Ligands
- Author
-
Cristina Garcia-Iriepa, Cecilia Hognon, Antonio Francés-Monerris, Isabel Iriepa, Tom Miclot, Giampaolo Barone, Antonio Monari, and Marco Marazzi
- Abstract
Since the end of 2019, the coronavirus SARS-CoV-2 has caused more than 180,000 deaths all over the world, still lacking a medical treatment despite the concerns of the whole scientific community. Human Angiotensin-Converting Enzyme 2 (ACE2) was recently recognized as the transmembrane protein serving as SARS-CoV-2 entry point into cells, thus constituting the first biomolecular event leading to COVID-19 disease. Here, by means of a state-of-the-art computational approach, we propose a rational evaluation of the molecular mechanisms behind the formation of the complex and of the effects of possible ligands. Moreover, binding free energy between ACE2 and the active Receptor Binding Domain (RBD) of the SARS-CoV-2 spike protein is evaluated quantitatively, assessing the molecular mechanisms at the basis of the recognition and the ligand-induced decreased affinity. These results boost the knowledge on the molecular grounds of the SARS-CoV-2 infection and allow to suggest rationales useful for the subsequent rational molecular design to treat severe COVID-19 cases.
- Published
- 2020
31. Photochemistry, chemiluminescence and dark photochemistry: computational advances (2018–2019)
- Author
-
Antonio Francés-Monerris, Javier Segarra-Martí, Antonio Monari, B.-W. Ding, Angelo Giussani, Javier Carmona-García, Daniel Roca-Sanjuán, Y.-J. Liu, and Miriam Navarrete-Miguel
- Subjects
chemistry.chemical_compound ,law ,Chemistry ,Excited state ,Light emission ,Boranes ,Spectroscopy ,Photochemistry ,Quantum chemistry ,Quantum computer ,Chemiluminescence ,law.invention ,Luminol - Abstract
Recent progress (2018–2019) in the field of quantum chemistry applied to the excited electronic state are presented in this book chapter. General developments of methods and theory are described first, followed by applications organised in three main topics, (i) photo-induced chemistry (photochemistry), (ii) chemically induced light emission (chemiluminescence) and (iii) chemically induced excited-state chemistry (dark photochemistry). We shall highlight in this occasion developments of machine learning, GPU and quantum computing algorithms for excited states, non-adiabatic new methodological approaches, sunlight chemistry of atmospheric mercury compounds, boranes and stilbenoids photochemistry, DNA spectroscopy and excited-state chemistry, the bio/chemiluminescence mechanism of luminol and distinct luciferin-luciferase complexes and retinal activation in the dark.
- Published
- 2020
32. A Series of Ultra-Efficient Blue Borane Fluorophores
- Author
-
Michael G. S. Londesborough, Tomáš Polívka, Antonio Francés-Monerris, Paul G. Waddell, Marcel Fuciman, Kamil Lang, Luis Cerdán, Kaplan Kirakci, Jonathan Bould, Daniel Roca-Sanjuán, William Clegg, Czech Science Foundation, Academy of Sciences of the Czech Republic, Generalitat Valenciana, and Ministerio de Ciencia, Innovación y Universidades (España)
- Subjects
Active laser medium ,Series (mathematics) ,010405 organic chemistry ,Hydride ,chemistry.chemical_element ,Borane ,Alkylation ,010402 general chemistry ,Laser ,01 natural sciences ,Combinatorial chemistry ,0104 chemical sciences ,law.invention ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,law ,Physical and Theoretical Chemistry ,Boron - Abstract
13 pags., 14 figs., 5 tabs., We present the first examples of alkylated derivatives of the macropolyhedral boron hydride, anti-B18H22, which is the gain medium in the first borane laser. This new series of ten highly stable and colorless organic-inorganic hybrid clusters are capable of the conversion of UVA irradiation to blue light with fluorescence quantum yields of unity. This study gives a comprehensive description of their synthesis, isolation, and structural characterization together with a delineation of their photophysical properties using a combined theoretical and experimental approach. Treatment of anti-B18H22 1 with RI (where R = Me or Et) in the presence of AlCl3 gives a series of alkylated derivatives, Rx-anti-B18H22-x (where x = 2 to 6), compounds 2-6, in which the 18-vertex octadecaborane cluster architectures are preserved and yet undergo a linear "polyhedral swelling", depending on the number of cluster alkyl substituents. The use of dichloromethane solvent in the synthetic procedure leads to dichlorination of the borane cluster and increased alkylation to give Me11-anti-B18H9Cl2 11, Me12-anti-B18H8Cl2 12, and Me13-anti-B18H7Cl2 13. All new alkyl derivatives are highly stable, extremely efficient (φF = 0.76-1.0) blue fluorophores (λems = 423-427 nm) and are soluble in a wide range of organic solvents and also a polystyrene matrix. The Et4-anti-B18H18 derivative 4b crystallizes from pentane solution in two phases with consequent multiabsorption and multiemission photophysical properties. An ultrafast transient UV-vis absorption spectroscopic study of compounds 4a and 4b reveals that an efficient excited-state absorption at the emission wavelength inhibits the laser performance of these otherwise remarkable luminescent molecules. All these new compounds add to the growing portfolio of octadecaborane-based luminescent species, and in an effort to broaden the perspective on their highly emissive photophysical properties, we highlight emerging patterns that successive substitutions have on the molecular size of the 18-vertex borane cluster structure and the distribution of the electron density within., This work was supported by the Czech Science Foundation (Project No. 18-20286S). We also acknowledge the working group Interactions of Inorganic Clusters, Cages, and Containers with Light within the AV21 Strategy, Czech Academy of Sciences. W.C. and P.G.W. thank Diamond Light Source for access to beamline I19 in remote-access mode (beam-time award CY22240). A.F.-M. is grateful to Generalitat Valenciana and the European Social Fund (postdoctoral contract APOSTD/2019/149 and project GV/2020/226) for financial support. A.F.-M. and D.R.-S. also acknowledge support from the Ministerio de Ciencia e Innovacioń (project CTQ2017- 87054-C2-2-P).
- Published
- 2020
33. Photodissociation Mechanisms of Major Mercury(II) Species in the Atmospheric Chemical Cycle of Mercury
- Author
-
Javier Carmona-García, Juan Z. Dávalos, Joseph S. Francisco, Alfonso Saiz-Lopez, A. Ulises Acuña, Carlos A. Cuevas, Daniel Roca-Sanjuán, Antonio Francés-Monerris, Douglas E. Kinnison, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Generalitat Valenciana, and European Commission
- Subjects
Thermal oxidation ,Chemical substance ,010405 organic chemistry ,Photodissociation ,chemistry.chemical_element ,Elemental mercury ,General Medicine ,General Chemistry ,010402 general chemistry ,Photochemistry ,7. Clean energy ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Mercury (element) ,Metal ,chemistry ,13. Climate action ,visual_art ,Atmospheric chemistry ,Thermal ,visual_art.visual_art_medium - Abstract
7 pags., 4 figs., Mercury is a contaminant of global concern that is transported throughout the atmosphere as elemental mercury Hg and its oxidized forms Hg and Hg. The efficient gas-phase photolysis of Hg and Hg has recently been reported. However, whether the photolysis of Hg leads to other stable Hg species, to Hg, or to Hg and its competition with thermal reactivity remain unknown. Herein, we show that all oxidized forms of mercury rapidly revert directly and indirectly to Hg by photolysis. Results are based on non-adiabatic dynamics simulations, in which the photoproduct ratios were determined with maximum errors of 3%. We construct for the first time a complete quantitative mechanism of the photochemical and thermal conversion between atmospheric Hg, Hg, and Hg compounds. These results reveal new fundamental chemistry that has broad implications for the global atmospheric Hg cycle. Thus, photoreduction clearly competes with thermal oxidation, with Hg being the main photoproduct of Hg photolysis in the atmosphere, which significantly increases the lifetime of this metal in the environment., Ministerio de Economía y Competitividad. Grant Numbers: CTQ2017-87054-C2-2-P, RYC- 2015-19234, MDM-2015-0538 Generalitat Valenciana. Grant Number: APOSTD/2019/149 European Research Council. Grant Number: ERC-2016-COG 726349 CLIMAHAL
- Published
- 2019
34. Triplet photosensitization mechanism of thymine by an oxidized nucleobase: from a dimeric model to DNA environment
- Author
-
Antonio Monari, Miguel A. Miranda, Antonio Francés-Monerris, Virginie Lhiaubet-Vallet, Cécilia Hognon, Laboratoire de Physique et Chimie Théoriques (LPCT), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), and Universitat Politècnica de València (UPV)
- Subjects
DNA damage ,5-Methyl-2-Pyrimidone Deoxyribonucleoside ,Dimer ,Population ,General Physics and Astronomy ,Pyrimidine dimer ,Charge-Transfer ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Photodynamic therapy ,Nucleobase ,chemistry.chemical_compound ,QUIMICA ORGANICA ,Nucleic-Acids ,[CHIM]Chemical Sciences ,Photosensitivity Disorders ,Physical and Theoretical Chemistry ,Cyclobutane Pyrimidine dimers ,education ,ComputingMilieux_MISCELLANEOUS ,Molecular-Dynamics ,Biological consequences ,education.field_of_study ,Singlet oxygen ,010405 organic chemistry ,DNA ,Cellular-DNA ,0104 chemical sciences ,Thymine ,chemistry ,Pyrimidine Dimers ,Nucleic acid ,UV-Irradiated DNA ,Oxidation-Reduction ,DNA Damage - Abstract
[EN] Nucleic acids are constantly exposed to external agents that can induce chemical and photochemical damage. In spite of the great advances achieved in the last years, some molecular mechanisms of DNA damage are not completely understood yet. A recent experimental report (I. Aparici-Espert et al., ACS Chem. Biol. 2018, 13, 542) proved the ability of 5-formyluracil (ForU), a common oxidatively generated product of thymine, to act as an intrinsic sensitizer of nucleic acids, causing single strand breaks and cyclobutane pyrimidine dimers in plasmid DNA. In the present contribution, we use theoretical methodologies to study the triplet photosensitization mechanism of thymine exerted by ForU in a model dimer and in DNA environment. The photochemical pathways in the former system are described combining the CASPT2 and TD-DFT methods, whereas molecular dynamics simulations and QM/MM calculations are employed for the DNA duplex. It is unambiguously shown that the (1)n,* state localised in ForU mediates the population of the triplet manifold, most likely the (3),* state centred in ForU, whereas the (3),* state localized in thymine can be populated via triplet-triplet energy transfer given the small energy barrier of, A. F. M. is grateful to Région Grand Est government (France) for the financial support. Spanish government (CTQ2015-70164P and CTQ2017-87054-C2-2-P projects) and Regional government (Prometeo/2017/075) are also acknowledged.
- Published
- 2018
35. Substitution of the laser borane anti-B18H22 with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides
- Author
-
Kamil Lang, Antonio Francés-Monerris, John D. Kennedy, William Clegg, Robert D. Kennedy, Jiří Dolanský, Tomáš Jelínek, Michael G. S. Londesborough, Ivana Císařová, and Daniel Roca-Sanjuán
- Subjects
010405 organic chemistry ,Quantum yield ,Nuclear magnetic resonance spectroscopy ,Borane ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,chemistry.chemical_compound ,Crystallography ,symbols.namesake ,chemistry ,Pyridine ,symbols ,Picoline ,van der Waals force ,Phosphorescence ,Derivative (chemistry) - Abstract
Reaction of anti-B18H221 with pyridine in neutral solvents gives sparingly soluble B16H18-3',8'-Py23a as the major product (ca. 53%) and B18H20-6',9'-Py22 (ca. 15%) as the minor product, with small quantities of B18H20-8'-Py 4 (ca. 1%) also being formed. The three new compounds 2, 3a and 4 are characterized by single-crystal X-ray diffraction analyses and by multinuclear multiple-resonance NMR spectroscopy. Compound 2 is of ten-vertex nido:ten-vertex arachno two-atoms-in-common architecture, long postulated for a species with borons-only cluster constitution, but previously elusive. Compound 3a is of unprecedented ten-vertex nido:eight-vertex arachno two-atoms-in-common architecture. The single-crystal X-ray diffraction analysis for the picoline derivative B16H18(NC5H4Me)23b, similarly obtained, is also presented. B18H20Py 4 is also previously unreported but is of known ten-vertex nido:ten-vertex nido two-atoms-in-common architecture of anti configuration, but now with the pyridine ligand positioned differently to other reported examples of B18H20L compounds. Factors behind the remarkably low solubility of 3a and 3b are elucidated in terms of electrostatic potential (ESP) calculations, polarity, and van der Waals complementarities. In view of contemporary developing high interest in the fluorescent properties of macropolyhedral boron-containing species, a detailed assessment of the photophysical characteristics of 3a and 4 is also presented. In contrast to the thermochromic fluorescence of 2 (from 620 nm brick-red at room temperature to 585 nm yellow at 8 K, quantum yield 0.15), compound 3a is only weakly phosphorescent in the yellow region (590 nm, quantum yield 0.01), whereas compound 4 exhibits no luminescence. The far more photoactive nature of compound 2 is associated with S1 excited-state minima structures that differ from each other only by the relative rotational positions of the pyridine substituents on its disubstituted ten-vertex {arachno-B10Py2}-subcluster. The wavelength and relative intensity of fluorescence from these structures depends on the rotational positions of the pyridine ligands, which in turn are influenced by temperature and/or rotational inhibition in the solid-state.
- Published
- 2018
36. Mechanism of activated chemiluminescence of cyclic peroxides: 1,2-dioxetanes and 1,2-dioxetanones
- Author
-
Wilhelm J. Baader, Felipe A. Augusto, Antonio Francés-Monerris, Daniel Roca-Sanjuán, Roland Lindh, Erick Leite Bastos, and Ignacio Fdez. Galván
- Subjects
010405 organic chemistry ,Chemistry ,General Physics and Astronomy ,010402 general chemistry ,Photochemistry ,Supermolecule ,01 natural sciences ,Peroxide ,LUCIFERIDAE ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,law ,Excited state ,Bioluminescence ,Light emission ,Singlet state ,Physical and Theoretical Chemistry ,Ground state ,Chemiluminescence - Abstract
Almost all chemiluminescent and bioluminescent reactions involve cyclic peroxides. The structure of the peroxide and reaction conditions determine the quantum efficiency of light emission. Oxidizable fluorophores, the so-called activators, react with 1,2-dioxetanones promoting the former to their first singlet excited state. This transformation is inefficient and does not occur with 1,2-dioxetanes; however, they have been used as models for the efficient firefly bioluminescence. In this work, we use the SA-CASSCF/CASPT2 method to investigate the activated chemiexcitation of the parent 1,2-dioxetane and 1,2-dioxetanone. Our findings suggest that ground state decomposition of the peroxide competes efficiently with the chemiexcitation pathway, in agreement with the available experimental data. The formation of non-emissive triplet excited species is proposed to explain the low emission efficiency of the activated decomposition of 1,2-dioxetanone. Chemiexcitation is rationalized considering a peroxide/activator supermolecule undergoing an electron-transfer reaction followed by internal conversion.
- Published
- 2017
37. Ultrafast dynamics in polycyclic aromatic hydrocarbons: the key case of conical intersections at higher excited states and their role in the photophysics of phenanthrene monomer
- Author
-
Marco Marazzi, Antonio Francés-Monerris, Andrea Cannizzo, Robert Häner, E. Lognon, Thomas Feurer, Caroline D. Bösch, Michela Gazzetto, Antonio Monari, Maryam Nazari, Simon Matthias Langenegger, Ariana Rondi, Institute of Applied Physics [Bern] (IAP), University of Bern, Department of Chemistry and Biochemistry [Bern], Laboratoire de Physique et Chimie Théoriques (LPCT), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), University of Alcalá / Department of Analytical Chemistry, Physical-Chemistry and Chemical Engineering, and Universidad de Alcalá - University of Alcalá (UAH)
- Subjects
010304 chemical physics ,530 Physics ,Supramolecular chemistry ,General Physics and Astronomy ,02 engineering and technology ,Conical intersection ,Phenanthrene ,021001 nanoscience & nanotechnology ,Branching (polymer chemistry) ,620 Engineering ,01 natural sciences ,chemistry.chemical_compound ,chemistry ,Chemical physics ,Excited state ,0103 physical sciences ,Femtosecond ,Ultrafast laser spectroscopy ,540 Chemistry ,[CHIM]Chemical Sciences ,570 Life sciences ,biology ,Physical and Theoretical Chemistry ,0210 nano-technology ,Spectroscopy ,ComputingMilieux_MISCELLANEOUS - Abstract
In this study we reveal the detailed photocycle of a phenanthrene monomer. Phenanthrene serves as a popular building block for supramolecular systems and as an archetypal molecule to study the photochemistry of polycyclic aromatic hydrocarbons. By means of femtosecond time-resolved UV-vis transient absorption spectroscopy and molecular modeling, we found that the first bright transition involves the second excited singlet state, which relaxes toward the lowest excited singlet state with a biphasic internal conversion through a conical intersection region: a fast coherent branching followed by an exceptionally slow (∼ps) incoherent internal conversion. We succeeded to pinpoint the complete relaxation pathways and to extract the relevant parameters, e.g., the branching ratio at the conical intersection and internal conversion rates.
- Published
- 2019
38. Effect of Iodination on the Photophysics of the Laser Borane
- Author
-
Michael G S, Londesborough, Jiří, Dolanský, Jonathan, Bould, Jakub, Braborec, Kaplan, Kirakci, Kamil, Lang, Ivana, Císařová, Pavel, Kubát, Daniel, Roca-Sanjuán, Antonio, Francés-Monerris, Lenka, Slušná, Eva, Noskovičová, and Dušan, Lorenc
- Abstract
Treatment of the laser borane
- Published
- 2019
39. Photophysical properties of bichromophoric Fe(II) complexes bearing an aromatic electron acceptor
- Author
-
Xavier Assfeld, Mariachiara Pastore, Philippe C. Gros, Antonio Monari, Antonio Francés-Monerris, Laboratoire de Physique et Chimie Théoriques (LPCT), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Lorrain de Chimie Moléculaire (L2CM), and Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
chemistry.chemical_classification ,Anthracene ,Materials science ,010304 chemical physics ,Infrared ,Electron acceptor ,010402 general chemistry ,Photochemistry ,01 natural sciences ,7. Clean energy ,0104 chemical sciences ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,chemistry.chemical_compound ,chemistry ,Atomic orbital ,Excited state ,0103 physical sciences ,Density functional theory ,Physical and Theoretical Chemistry ,Luminescence ,Carbene ,ComputingMilieux_MISCELLANEOUS - Abstract
The replacement of heavy metals used by industry to produce optical devices would considerably reduce the environmental and economic cost of man-made technology. A possible strategy relies on the employment of lighter and more abundant metals like iron. The exploitability of the photophysics of Fe(II) complexes is, however, generally limited by their short excited-state lifetimes and poor emission properties. The present work studies the impact of appending an electron acceptor (anthracene) to N-heterocyclic carbene (NHC) iron complexes with the aim to trap the excited-state energy and, therefore, delay the excited-state decay of the considered iron compounds. Hence, the photophysical properties of six prototypes (built with different spacers between the NHC ligand and the anthracene moieties) have been studied by using time-dependent density functional theory and by determining the natural transition orbitals of the excited states. The computational results suggest that ethynyl bridges induce dual absorption properties, covering red and infrared wavelengths in addition to the violet–blue absorption of the metal-to-ligand charge transfer band, already reported for the parent compound. The nature of the lowest lying triplet states indicates that, for all the considered prototypes, the excitation involves π* orbitals localized over anthracene, confirming its electron acceptor capabilities and suggesting a possible equilibrium between different excited states that might lead to enhanced excited-state lifetimes and/or boosted luminescence properties.
- Published
- 2019
40. Photochromic System among Boron Hydrides: The Hawthorne Rearrangement
- Author
-
Josep M. Oliva-Enrich, Kamil Lang, Antonio Francés-Monerris, Josef Holub, Daniel Roca-Sanjuán, and Drahomír Hnyk
- Subjects
Photochromism ,chemistry ,chemistry.chemical_element ,Molecule ,General Materials Science ,Boron Hydrides ,Physical and Theoretical Chemistry ,Photochemistry ,Boron ,Chemical reaction ,Isomerization - Abstract
Photoswitchable molecules have attracted wide interest for many applications in chemistry, physics, and materials science. In this work, we revisit the reversible photochemical and thermal rearrangements of the two B20H182– isomers reported by Hawthorne and Pilling in 1966, whose mechanism had not been understood so far. We investigate the rearrangements by means of a joint experimental and computational study with the outcome that B20H182– represents the first boron-based photochromic system ever reported. Both photochemical and thermal isomerizations occur through the same intermediate and involve a diamond–square–diamond (DSD) mechanism. Given the absence within boron chemistry of named chemical reactions as opposed to organic chemistry, we propose to label the B20H182– photo- and thermal isomerization processes as the Hawthorne rearrangement.
- Published
- 2019
41. A Combined Experimental and Theoretical Approach to the Photogeneration of 5,6-Dihydropyrimidin-5-yl Radicals in Nonaqueous Media
- Author
-
Isabel Aparici-Espert, Antonio Francés-Monerris, Miguel A. Miranda, Gemma M. Rodríguez-Muñiz, Virginie Lhiaubet-Vallet, and Daniel Roca-Sanjuán
- Subjects
Ketone ,THYMIDINE ,DNA damage ,Radical ,Reactive intermediate ,010402 general chemistry ,Photochemistry ,Hydrogen atom abstraction ,01 natural sciences ,QUIMICA ORGANICA ,AQUEOUS-SOLUTIONS ,QUIMICA ANALITICA ,STRAND SCISSION ,Reactivity (chemistry) ,REPAIR ,chemistry.chemical_classification ,Aqueous solution ,010405 organic chemistry ,Organic Chemistry ,INDEPENDENT GENERATION ,0104 chemical sciences ,5,6-DIHYDROTHYMID-5-YL ,DNA-DAMAGE ,chemistry ,2ND-ORDER PERTURBATION-THEORY ,RADIATION ,Flash photolysis ,HYDROGEN-ATOM ABSTRACTION - Abstract
The chemical fate of radical intermediates is relevant to understand the biological effects of radiation and to explain formation of DNA lesions. A direct approach to selectively generate the putative reactive intermediates is based on the irradiation of photolabile precursors. But, to date, radical formation and reactivity have only been studied in aqueous media, which do not completely mimic the micro environment provided by the DNA structure and its complexes with proteins. Thus, it is also important to evaluate the photogeneration of nucleoside-based radicals in nonaqueous media. The attention here is focused on the independent generation of 5,6-dihydropyrimidin-5-yl radicals in organic solvent through the synthesis of new lipophilic tert-butyl ketone precursors. Formation of 5,6-dihydro-2'-deoxyuridin-S-yl and 5,6-dihydrothymidin-5-yl radicals has first been confirmed by using a new nitroxide-derived profluorescent radical trap. Further evidence has been obtained by nanosecond laser flash photolysis through detection of long-lived transients. Finally, the experimental data are corroborated by multiconfigurational ab initio CASPT2//CASSCF methodology., Spanish Government (CTQ2012-32621, CTQ2015-70164-P, CTQ2014-58624-P, RIRAAF RETICS RD12/0013/0009, Severo Ochoa program/SEV-2012-0267, Maria de Maetzu program/MDM-2015-0538, BES-2011-048326 and BES-2013-066566, JCI-2012-13431) and Generalitat Valenciana (Prometeo 11/2013/005 and GV2015-057) are gratefully acknowledged. Dr. M. Luisa Marin is also acknowledged for her help during laser flash photolysis experiments.
- Published
- 2016
42. Experimental and Theoretical Study on the Cycloreversion of a Nucleobase-Derived Azetidine by Photoinduced Electron Transfer
- Author
-
Miriam Navarrete-Miguel, Miguel A. Miranda, Antonio Francés-Monerris, Virginie Lhiaubet-Vallet, Gemma M. Rodríguez-Muñiz, Daniel Roca-Sanjuán, and Ana B. Fraga‐Timiraos
- Subjects
Models, Molecular ,Photochemistry ,Radical ,Azetidine ,Pyrimidine dimer ,010402 general chemistry ,01 natural sciences ,Catalysis ,Photoinduced electron transfer ,Nucleobase ,Cyclobutane ,Electron transfer ,Electron Transport ,chemistry.chemical_compound ,QUIMICA ORGANICA ,Uracil ,Cycloaddition ,Aza Compounds ,Cycloaddition Reaction ,010405 organic chemistry ,Organic Chemistry ,General Chemistry ,Radicals ,Photochemical Processes ,0104 chemical sciences ,Thymine ,Density functional calculations ,Pyrimidines ,chemistry ,Pyrimidine Dimers ,Azetidines ,Oxidation-Reduction - Abstract
[EN] Azetidines are interesting compounds in medicine and chemistry as bioactive scaffolds and synthetic intermediates. However, photochemical processes involved in the generation and fate of azetidine-derived radical ions have scarcely been reported. In this context, the photoreduction of this four-membered heterocycle might be relevant in connection with the DNA (6-4) photoproduct obtained from photolyase. Herein, a stable azabipyrimidinic azetidine (AZT(m)), obtained from cycloaddition between thymine and 6-azauracil units, is considered to be an interesting model of the proposed azetidine-like intermediate. Hence, its photoreduction and photo-oxidation are thoroughly investigated through a multifaceted approach, including spectroscopic, analytical, and electrochemical studies, complemented by CASPT2 and DFT calculations. Both injection and removal of an electron result in the formation of radical ions, which evolve towards repaired thymine and azauracil units. Whereas photoreduction energetics are similar to those of the cyclobutane thymine dimers, photo-oxidation is clearly more favorable in the azetidine. Ring opening occurs with relatively low activation barriers (< 13 kcal mol(-1)) and the process is clearly exergonic for photoreduction. In general, a good correlation has been observed between the experimental results and theoretical calculations, which has allowed a synergic understanding of the phenomenon., The Spanish Government (CTQ2015-70164-P, CTQ2017-87054-C2-2-P, SVP-2013-068057 grants to A.B.F.-R. and RYC-2015-19234 grant to D.R.-S.) and the Valencia Regional Government (Prometeo/2017/075) are acknowledged for financial support. A.F.-M. is grateful to the Region Grand Est government (France) and the Universite de Lorraine for their financial support.
- Published
- 2018
43. Substitution of the laser borane anti-B
- Author
-
Michael G S, Londesborough, Jiří, Dolanský, Tomáš, Jelínek, John D, Kennedy, Ivana, Císařová, Robert D, Kennedy, Daniel, Roca-Sanjuán, Antonio, Francés-Monerris, Kamil, Lang, and William, Clegg
- Abstract
Reaction of anti-B
- Published
- 2018
44. Regioselectivity of the OH Radical Addition to Uracil in Nucleic Acids. A Theoretical Approach Based on QM/MM Simulations
- Author
-
Iñaki Tuñón, Daniel Roca-Sanjuán, Juan Aranda, and Antonio Francés-Monerris
- Subjects
Stereochemistry ,010402 general chemistry ,01 natural sciences ,Nucleobase ,QM/MM ,chemistry.chemical_compound ,Computational chemistry ,0103 physical sciences ,Physical and Theoretical Chemistry ,Nucleic acid structure ,Uracil ,010304 chemical physics ,Hydroxyl Radical ,RNA ,Water ,Stereoisomerism ,0104 chemical sciences ,Computer Science Applications ,Solutions ,chemistry ,Nucleic acid ,Quantum Theory ,DNA ,Macromolecule - Abstract
Oxidation of nucleic acids is ubiquitous in living beings under metabolic impairments and/or exposed to external agents such as radiation, pollutants, or drugs, playing a central role in the development of many diseases mediated by DNA/RNA degeneration. Great efforts have been devoted to unveil the molecular mechanisms behind the OH radical additions to the double bonds of nucleobases; however, the specific role of the biological environment remains relatively unexplored. The present contribution tackles the study of the OH radical addition to uracil from the gas phase to a full RNA macromolecule by means of quantum-chemistry methods combined with molecular dynamics simulations. It is shown that, in addition to the intrinsic reactivity of each position driven by the electronic effects, the presence of bridge water molecules intercalated into the RNA structure favors the addition to the C5 position of uracil in biological conditions. The results also suggest that diffusion of the OH radical does not play a relevant role in the regioselectivity of the reaction, which is mainly controlled at the chemical stage of the addition process.
- Published
- 2017
45. Triplet versus singlet chemiexcitation mechanism in dioxetanone: a CASSCF/CASPT2 study
- Author
-
Roland Lindh, Antonio Francés-Monerris, Ignacio Fernández Galván, and Daniel Roca-Sanjuán
- Subjects
education.field_of_study ,010304 chemical physics ,Chemistry ,Population ,Quantum yield ,010402 general chemistry ,01 natural sciences ,Potential energy ,0104 chemical sciences ,Chemical energy ,Chemical physics ,Excited state ,0103 physical sciences ,Singlet fission ,Singlet state ,Physical and Theoretical Chemistry ,Atomic physics ,Triplet state ,education - Abstract
Chemiluminescence is a fundamental process of chemistry consisting in the conversion of chemical energy stored in chemical bonds into light. It is used by nature and by man-made technology, being especially relevant in chemical analysis. The understanding of the phenomenon strongly relies in the study of peroxide models such as 1,2-dioxetanones. In the present contribution, the singlet S 2 and the triplet T 2 potential energy surfaces of the unimolecular decomposition of 1,2-dioxetanone have been mapped along the O–O and C–C bond coordinates on the grounds of the multiconfigurational CASPT2//CASSCF approach. Results confirm the energy degeneracy between T 2, T 1, S 1, and S 0 at the TS region, whereas S 2 is unambiguously predicted at higher energies. Triplet-state population is also supported by the spin–orbit couplings between the singlet and triplet states partaking in the process. In particular, the first-principle calculations show that decomposition along the T 2 state is a competitive process, having a small (~3 kcal/mol) energy barrier from the ground-state TS structure. The present findings can explain the higher quantum yield of triplet-state population with respect to the excited singlet states recorded experimentally for the unimolecular decomposition of 1,2-dioxetanone models.
- Published
- 2017
46. Theoretical Study of the Hydroxyl Radical Addition to Uracil and Photochemistry of the Formed U6OH• Adduct
- Author
-
Antonio Francés-Monerris, Daniel Roca-Sanjuán, and Manuela Merchán
- Subjects
Models, Molecular ,chemistry.chemical_classification ,Pyrimidine ,Double bond ,Hydroxyl Radical ,Photochemistry ,Uracil ,Surfaces, Coatings and Films ,Adduct ,Nucleobase ,DNA Adducts ,chemistry.chemical_compound ,chemistry ,Materials Chemistry ,Quantum Theory ,Hydroxyl radical ,Physical and Theoretical Chemistry ,Solvent effects ,Visible spectrum - Abstract
Hydroxyl radical ((•)OH) is produced in biological systems by external or endogenous agents. It can damage DNA/RNA by attacking pyrimidine nucleobases through the addition to the C5═C6 double bond. The adduct resulting from the attachment at the C5 position prevails in the experimental measurements, although the reasons for this preference remain unclear. The first aim of this work is therefore to shed light on the comprehension of this important process. Thus, the thermal (•)OH addition to the C5═C6 double bond of uracil has been studied theoretically by using DFT, MP2, and the multiconfigurational CASPT2//CASSCF methodologies. The in-vacuo results obtained with the latter protocol plus the analysis of solvent effects support the experimental observation. A significant lower barrier height is predicted for the C5 pathway with respect to that of the C6 route. In contrast to the C5 adduct, the C6 adduct is able to absorb visible light. Hence, the second aim of the work is to study the photochemistry of this species using the CASPT2//CASSCF methodology within the framework of the photochemical reaction path approach (PRPA). The nonradiative decay to the ground state of this compound has been characterized. A photoreactive character is predicted for the C6 adduct in the excited states according to the presence of excited-state minima along the main decay channel. Finally, a new mechanism of photodissociation has been explored, which implies the photoinduced regeneration of the canonical nucleobase by irradiating with visible light, being therefore relevant in RNA protection against damage by reactive oxygen species.
- Published
- 2014
47. Mechanism of the OH Radical Addition to Adenine from Quantum-Chemistry Determinations of Reaction Paths and Spectroscopic Tracking of the Intermediates
- Author
-
Antonio Francés-Monerris, Daniel Roca-Sanjuán, and Manuela Merchán
- Subjects
0301 basic medicine ,Chemistry ,Hydroxyl Radical ,Adenine ,Organic Chemistry ,010402 general chemistry ,01 natural sciences ,Quantum chemistry ,0104 chemical sciences ,Nucleobase ,Adduct ,03 medical and health sciences ,030104 developmental biology ,Pyrimidines ,Mechanism (philosophy) ,Computational chemistry ,Excited state ,Organic chemistry ,Nucleic Acid Conformation ,Quantum Theory ,Density functional theory ,Reactivity (chemistry) - Abstract
The OH radical is a well-known mediator in the oxidation of biological structures like DNA. Over the past decades, the precise events taking place after reaction of DNA nucleobases with OH radical have been widely investigated by the scientific community. Thirty years after the proposal of the main routes for the reaction of •OH with adenine (Vieira, A.; Steenken, S. J. Am. Chem. Soc. 1990, 112, 6986−6994), the present work demonstrates that the OH radical addition to C4 position is a minor pathway. Instead, the dehydration process is mediated by the A5OH adduct. Conclusions are based on density functional theory calculations for the ground-state reactivity and highly accurate multiconfigurational computations for the excited states of the radical intermediates. The methodology has been also used to study the mechanism giving rise to the mutagens 8-oxoA and FAPyA. Taking into account the agreement between the experimental data and the theoretical results, it is concluded that addition to the C5 and C8 pos...
- Published
- 2016
48. Mechanism of excited state deactivation of indan-1-ylidene and fluoren-9-ylidene malononitriles
- Author
-
Antonio Francés-Monerris, Igor Schapiro, Massimo Olivucci, Daniel Roca-Sanjuán, and Leandro A. Estrada
- Subjects
chemistry.chemical_classification ,010304 chemical physics ,Double bond ,General Physics and Astronomy ,Conical intersection ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Quantum chemistry ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Excited state ,0103 physical sciences ,Ultrafast laser spectroscopy ,Physical and Theoretical Chemistry ,Spectroscopy ,Isomerization ,Malononitrile - Abstract
Herein, we report complementary computational and experimental evidence supporting the existence, for indan-1-ylidene malononitrile and fluoren-9-ylidene malononitrile, of a non-radiative decay channel involving double bond isomerisation motion. The results of UV-Vis transient absorption spectroscopy highlight that the decay takes place within hundreds of picoseconds. In order to understand the related molecular mechanism, photochemical reaction paths were computed by employing multiconfigurational quantum chemistry. The results indicate that the excited state deactivation occurs via concerted double bond twisting of the dicyanovinyl (DCV) unit coupled with a pyramidalisation of its substituted carbon. It is also shown that the observed differences in the excited state lifetimes when passing from indan-1-ylidene malononitrile to fluoren-9-ylidene are associated with the change in the topography of the conical intersection driving the decay from intermediate to sloped, respectively.
- Published
- 2016
49. Theoretical study on the excited-state π-stacking versus intermolecular hydrogen-transfer processes in the guanine–cytosine/cytosine trimer
- Author
-
Javier Segarra-Martí, Antonio Francés-Monerris, Manuela Merchán, and Daniel Roca-Sanjuán
- Subjects
010405 organic chemistry ,Chemistry ,Guanine ,Intermolecular force ,Ab initio ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Nucleobase ,Reaction coordinate ,chemistry.chemical_compound ,Chemical physics ,Computational chemistry ,Excited state ,Molecule ,Physical and Theoretical Chemistry ,Cytosine - Abstract
Understanding the complex events that take place in nucleic acids upon UV light exposure constitutes a key step in the comprehension of life evolution, as well as in the determination of the mechanisms that can originate genetic mutations and lead to the development of diseases like skin cancer. Over the last decade, intra- and inter-strand processes that depend on the relative movements of the DNA strands have been proposed as photochemical pathways capable to deactivate the excess of energy provided by UV light. In order to elucidate the relative importance of both types of photochemical routes, high-level ab initio quantum chemical computations have been conducted on a model formed by the guanine–cytosine base pair and an additional π-stacked cytosine yielding a GC/C trimeric system. The effect of the π-stacking has been evaluated along the reaction coordinate of the stepwise double-hydrogen-transfer (SDHT) mechanism reported in a previous study (Sauri et al. in J Chem Theory Comput 9: 481–496, 2013). It becomes apparent from the present findings that the SDHT process is available at a wide range of cytosine–cytosine intermolecular distances. At a face-to-face orientation of the two cytosine molecules with an intermolecular distance of 3.4 A, the highly effective π-stacking interaction favours the formation of the CC excimer of the canonical nucleobases. Nevertheless, no barriers are found for the inter-strand mechanism. At larger interacting distances (4.0 A), both intra-strand photochemistry and inter-strand photochemistry have to be simultaneously considered, whereas at very short distances (2.8 A) the SDHT process is significantly hindered. The present work confirms the availability of the intermolecular hydrogen transfer in a wide region of the distinct hypersurfaces explored. As compared to the canonical WC base pair, the tautomeric form has more favourable SDHT channels.
- Published
- 2016
50. Advances in computational photochemistry and chemiluminescence of biological and nanotechnological molecules
- Author
-
Roland Lindh, Daniel Roca-Sanjuán, Ya-Jun Liu, Antonio Francés-Monerris, Pooria Farahani, and Ignacio Fernández Galván
- Subjects
law ,Chemistry ,Ab initio ,Nanotechnology ,Photochemistry ,Chemiluminescence ,law.invention - Abstract
Recent advances (2014–2015) in computational photochemistry and chemiluminescence derive from the development of theory and from the application of state-of-the-art and new methodology to challenging electronic-structure problems. Method developments have mainly focused, first, on the improvement of approximate and cheap methods to provide a better description of non-adiabatic processes, second, on the modification of accurate methods in order to decrease the computation time and, finally, on dynamics approaches able to provide information that can be directly compared with experimental data, such as yields and lifetimes. Applications of the ab initio quantum-chemistry methods have given rise to relevant findings in distinct fields of the excited-state chemistry. We briefly summarise, in this chapter, the achievements on photochemical mechanisms and chemically-induced excited-state phenomena of interest in biology and nanotechnology.
- Published
- 2016
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.