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Dutta M, Bisht S, Ghosh P, Chilug AI, Mann D, Enachescu C, Shatruk M, Chakraborty P. Combined Experimental and Mechanoelastic Modeling Studies on the Low-Spin Stabilized Mixed Crystals of 3D Oxalate-Based Coordination Materials. Inorg Chem 2023; 62:15050-15062. [PMID: 37677120 DOI: 10.1021/acs.inorgchem.3c01919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2023]
Abstract
Structural studies involving single-crystal and powder X-ray diffraction analysis have been performed on dehydrated coordination networks of the [NixCo1-x(bpy)3][LiCr(ox)3] series, 0 ≤ x ≤ 1, (bpy = 2,2'-bipyridine). The high-symmetry cubic 3D structure of these materials is formed by oxalate anions bridging alternating Cr3+ and Li+ ions into an anionic framework, which contains large cavities that incorporate the [NixCo1-x(bpy)3]2+ cations. Irrespective of the Co/Ni ratio, all of the mixed samples are phase-pure and retain the high-symmetry cubic structure, with the lattice parameters gradually decreasing upon increasing Ni(II) concentration. The influence of the Ni(II) dilution on the magnetic behavior of these materials is substantial. For pure [Co(bpy)3][LiCr(ox)3], a gradual but incomplete thermal spin-crossover is evident due to the effect of the chemical pressure applied by the [LiCr(ox)3]2- framework, which stabilizes the low-spin (LS) 2E state relative to the high-spin (HS) 4T1 state of the Co(II) ion. Upon increasing the Ni(II) content, the spin-crossover becomes even more gradual and incomplete and eventually is not observed for pure [Ni(bpy)3][LiCr(ox)3]. The average spin-crossover temperature increases with the increasing Ni(II) content, suggesting a higher degree of chemical pressure applied by the oxalate framework manifested by changing the ΔE0HL toward positive values. The magnetic behavior of all these framework materials has been explained by the mechanoelastic model, considering different radii for Co and Ni molecules and different interactions between Co-Co sites and Co-Ni sites. The model reproduced the incomplete transition, with the HS residual fraction at 300 K decreasing with increasing Ni concentration, and provided microscopic snapshots of the systems, showing how the existence of impurities prevented the spreading of Co atoms in the HS state.
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Affiliation(s)
- Mousumi Dutta
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Shubham Bisht
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, Florida 32306, United States
| | - Prabir Ghosh
- Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | | | - Dallas Mann
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, Florida 32306, United States
| | | | - Michael Shatruk
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, Florida 32306, United States
| | - Pradip Chakraborty
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
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Ailloud A, Udrescu C, Horn S, Enachescu C, Créhange G, Sargos P, Supiot S, Zilli T, Lapierre A, Chapet O. [Relationship between doses to anatomical structures and erectile dysfunction after radiotherapy for prostate cancer: A systematic review]. Cancer Radiother 2023; 27:548-561. [PMID: 37596125 DOI: 10.1016/j.canrad.2023.07.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 07/12/2023] [Indexed: 08/20/2023]
Abstract
PURPOSE During prostatic radiotherapy, damage to several anatomical structures could be the cause of erectile dysfunction: corpora cavernosa, internal pudendal arteries, penile bulb, and neurovascular bundles. Numerous studies have analysed the correlations between the dose received by these structures and erectile function. The objective of this article is to make a systematic review on current knowledge. MATERIALS AND METHODS A systematic review was performed in the Medline database using the search engine PubMed. Keywords for the search included: erectile dysfunction, penile bulb, corpora cavernosa, cavernosum, neurovascular bundles, radiation therapy, cancer, prostate cancer. The selected articles must study a correlation between erectile dysfunction and the dose received by anatomical structures. A total of 152 articles were identified. Of these 152 articles, 45 fulfilled the defined selection criteria. RESULTS For corpora cavernosa, seven studies were identified, only two studies demonstrated a significant correlation between the dose received by corpora cavernosa and the occurrence of erectile dysfunction. For penile bulb, only 15 of 23 studies showed a correlation. A mean dose on the penile bulb greater than 20Gy was found to be predictive of erectile dysfunction. None of the eight trials concerning neurovascular bundles succeeded to show a correlation between dose and erectile dysfunction. Only one study evaluated the relationship between the dose received by internal pudendal arteries and erectile dysfunction but was found to be negative. However, vessels-sparing studies showed good results on erectile function preservation without compromising the target volume. CONCLUSION We currently have little data to show a correlation between erectile dysfunction and sexual structures. It would be necessary to have additional prospective studies evaluating the impact of an optimization on these sexual structures on erectile dysfunction.
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Affiliation(s)
- A Ailloud
- Département de radiothérapie-oncologie, hôpital Lyon-Sud, Pierre-Bénite, France
| | - C Udrescu
- Département de radiothérapie-oncologie, hôpital Lyon-Sud, Pierre-Bénite, France; Université Claude-Bernard Lyon 1, Pierre-Bénite, France
| | - S Horn
- Département de radiothérapie-oncologie, hôpital Lyon-Sud, Pierre-Bénite, France
| | - C Enachescu
- Département de radiothérapie-oncologie, hôpital Lyon-Sud, Pierre-Bénite, France
| | - G Créhange
- Département de radiothérapie-oncologie, institut Curie, Paris, France; Université PSL, université Paris-Saclay, U1288, Inserm Lito, Orsay, France
| | - P Sargos
- Département de radiothérapie-oncologie, institut Bergonié, Bordeaux, France
| | - S Supiot
- Département de radiothérapie-oncologie, institut de cancérologie de l'Ouest, centre René-Gauducheau, Saint-Herblain, France
| | - T Zilli
- Département de radiothérapie-oncologie, hôpitaux universitaires de Genève, Genève, Suisse; Université de médecine de Genève, Genève, Suisse
| | - A Lapierre
- Département de radiothérapie-oncologie, hôpital Lyon-Sud, Pierre-Bénite, France; Université Claude-Bernard Lyon 1, Pierre-Bénite, France
| | - O Chapet
- Département de radiothérapie-oncologie, hôpital Lyon-Sud, Pierre-Bénite, France; Université Claude-Bernard Lyon 1, Pierre-Bénite, France.
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Hu Y, Picher M, Palluel M, Daro N, Freysz E, Stoleriu L, Enachescu C, Chastanet G, Banhart F. Laser-Driven Transient Phase Oscillations in Individual Spin Crossover Particles. Small 2023; 19:e2303701. [PMID: 37246252 DOI: 10.1002/smll.202303701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Indexed: 05/30/2023]
Abstract
An unusual expansion dynamics of individual spin crossover nanoparticles is studied by ultrafast transmission electron microscopy. After exposure to nanosecond laser pulses, the particles exhibit considerable length oscillations during and after their expansion. The vibration period of 50-100 ns is of the same order of magnitude as the time that the particles need for a transition from the low-spin to the high-spin state. The observations are explained in Monte Carlo calculations using a model where elastic and thermal coupling between the molecules within a crystalline spin crossover particle govern the phase transition between the two spin states. The experimentally observed length oscillations are in agreement with the calculations, and it is shown that the system undergoes repeated transitions between the two spin states until relaxation in the high-spin state occurs due to energy dissipation. Spin crossover particles are therefore a unique system where a resonant transition between two phases occurs in a phase transformation of first order.
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Affiliation(s)
- Yaowei Hu
- Institut de Physique et Chimie des Matériaux UMR 7504, Université de Strasbourg & CNRS, Strasbourg, 67034, France
| | - Matthieu Picher
- Institut de Physique et Chimie des Matériaux UMR 7504, Université de Strasbourg & CNRS, Strasbourg, 67034, France
| | - Marlène Palluel
- Université de Bordeaux, CNRS, Bordeaux INP (ICMCB-UMR 5026), Pessac, 33600, France
| | - Nathalie Daro
- Université de Bordeaux, CNRS, Bordeaux INP (ICMCB-UMR 5026), Pessac, 33600, France
| | - Eric Freysz
- Université de Bordeaux, CNRS UMR 5798, LOMA, Talence cedex, 33405, France
| | - Laurentiu Stoleriu
- Faculty of Physics, Alexandru Ioan Cuza University, Iasi, 700506, Romania
| | - Cristian Enachescu
- Faculty of Physics, Alexandru Ioan Cuza University, Iasi, 700506, Romania
| | - Guillaume Chastanet
- Université de Bordeaux, CNRS, Bordeaux INP (ICMCB-UMR 5026), Pessac, 33600, France
| | - Florian Banhart
- Institut de Physique et Chimie des Matériaux UMR 7504, Université de Strasbourg & CNRS, Strasbourg, 67034, France
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Kelai M, Tauzin A, Railean A, Repain V, Lagoute J, Girard Y, Rousset S, Otero E, Mallah T, Boillot ML, Enachescu C, Bellec A. Interface versus Bulk Light-Induced Switching in Spin-Crossover Molecular Ultrathin Films Adsorbed on a Metallic Surface. J Phys Chem Lett 2023; 14:1949-1954. [PMID: 36787373 DOI: 10.1021/acs.jpclett.2c03733] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Spin-crossover molecules present the unique property of having two spin states that can be controlled by light excitation at low temperature. Here, we report on the photoexcitation of [FeII((3, 5-(CH3)2Pz)3BH)2] (Pz = pyrazolyl) ultrathin films, with thicknesses ranging from 0.9 to 5.3 monolayers, adsorbed on Cu(111) substrate. Using X-ray absorption spectroscopy measurements, we confirm the anomalous light-induced spin-state switching observed for sub-monolayer coverage and demonstrate that it is confined to the first molecular layer in contact with the metallic substrate. For higher coverages, the well-known light-induced excited spin-state trapping effect is recovered. Combining continuous light excitation with thermal cycling, we demonstrate that at low temperature light-induced thermal hysteresis is measured for the thicker films, while for sub-monolayer coverage, the light enables extension of the thermal conversion over a large temperature range. Mechanoelastic simulations underline that, due to the intermolecular interactions, opposite behaviors are observed in the different layers composing the films.
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Affiliation(s)
- Massine Kelai
- Université Paris Cité, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, F-75013 Paris, France
| | - Arthur Tauzin
- Université Paris-Saclay, Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, UMR 8182, 91400 Orsay, France
| | - Anastasia Railean
- Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Iasi 700506, Romania
| | - Vincent Repain
- Université Paris Cité, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, F-75013 Paris, France
| | - Jérôme Lagoute
- Université Paris Cité, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, F-75013 Paris, France
| | - Yann Girard
- Université Paris Cité, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, F-75013 Paris, France
| | - Sylvie Rousset
- Université Paris Cité, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, F-75013 Paris, France
| | - Edwige Otero
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, 91192 Gif sur Yvette, France
| | - Talal Mallah
- Université Paris-Saclay, Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, UMR 8182, 91400 Orsay, France
| | - Marie-Laure Boillot
- Université Paris-Saclay, Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, UMR 8182, 91400 Orsay, France
| | - Cristian Enachescu
- Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Iasi 700506, Romania
| | - Amandine Bellec
- Université Paris Cité, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, F-75013 Paris, France
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Chakraborty P, Sy M, Fourati H, Delgado T, Dutta M, Das C, Besnard C, Hauser A, Enachescu C, Boukheddaden K. Optical microscopy imaging of the thermally-induced spin transition and isothermal multi-stepped relaxation in a low-spin stabilized spin-crossover material. Phys Chem Chem Phys 2022; 24:982-994. [PMID: 34918013 DOI: 10.1039/d1cp04321h] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The thermal spin transition and the photo-induced high-spin → low-spin relaxation of the prototypical [Fe(ptz)6](BF4)2 spin-crossover compound (ptz = 1-propyltetrazole) diluted in the isostructural ruthenium host lattice [Ru(ptz)6](BF4)2, which stabilizes the Fe(II) low-spin state, have been investigated. We demonstrate the presence of a crystallographic phase transition around 145 K (i.e. from the high-temperature ordered high-spin phase to a low-temperature disordered low-spin phase) upon slow cooling from room temperature. This crystallographic phase transition is decoupled from the thermal spin transition. A supercooled ordered low-spin phase is observed as in the pure Fe(II) analogue upon fast cooling. A similar order-disorder phase transition is also observed for pure [Ru(ptz)6](BF4)2 but at relatively higher temperature (i.e. at around 150 K) without involving any spin transition. For Ru-diluted [Fe(ptz)6]2+, the crystallographic phase transition as well as strong cooperative effects involving various degrees of elastic frustration are at the origin of stepped sigmoidal high-spin → low-spin relaxation curves, which are modelled in the framework of a classical mean field model, considering both the tunnelling and thermally activated regimes. Optical microscopy studies performed on two different single crystals showed the existence of hysteretic thermal transitions with slight domain formation, hardly visible in the static crystal images. This behavior is attributed to the double effect upon Ru dilution, which decreases the cooperative character of the transition and simultaneously reduces the optical contrast between the LS and HS states. Moreover, the transition temperature revealed to be slightly crystal dependent, highlighting the crucial role of the spatial distribution of Ru from one crystal to another, in addition to the well-known effects of crystal shape and size.
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Affiliation(s)
- Pradip Chakraborty
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur-721302, India.
| | - Mouhamadou Sy
- Université Assane Seck de Ziguinchor, Département de Physique, LCPM, BP 523 Diabir, Ziguinchor 27000, Sénégal
| | - Houcem Fourati
- Université Paris-Saclay, UVSQ, CNRS, GEMAC, 45 Avenue des Etats Unis 78035, Versailles, France.
| | - Teresa Delgado
- Département de Chimie Physique, Université de Genève, 30, Quai Ernest-Ansermet, CH-1211, Genève 4, Switzerland.,Chimie ParisTech-CNRS, IRCP (PSL), 11 rue P. et M. Curie, 75005 Paris, France
| | - Mousumi Dutta
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur-721302, India.
| | - Chinmoy Das
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur-721302, India.
| | - Céline Besnard
- Laboratoire de Cristallographie, Université de Genève, 24, Quai Ernest-Ansermet, CH-1211, Genève 4, Switzerland
| | - Andreas Hauser
- Département de Chimie Physique, Université de Genève, 30, Quai Ernest-Ansermet, CH-1211, Genève 4, Switzerland
| | | | - Kamel Boukheddaden
- Université Paris-Saclay, UVSQ, CNRS, GEMAC, 45 Avenue des Etats Unis 78035, Versailles, France.
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Hu Y, Picher M, Tran NM, Palluel M, Stoleriu L, Daro N, Mornet S, Enachescu C, Freysz E, Banhart F, Chastanet G. Photo-Thermal Switching of Individual Plasmonically Activated Spin Crossover Nanoparticle Imaged by Ultrafast Transmission Electron Microscopy. Adv Mater 2021; 33:e2105586. [PMID: 34601766 DOI: 10.1002/adma.202105586] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/22/2021] [Indexed: 06/13/2023]
Abstract
Spin crossover (SCO) is a promising switching phenomenon when implemented in electronic devices as molecules, thin films or nanoparticles. Among the properties modulated along this phenomenon, optically induced mechanical changes are of tremendous importance as they can work as fast light-induced mechanical switches or allow to investigate and control microstructural strains and fatigability. The development of characterization techniques probing nanoscopic behavior with high spatio-temporal resolution allows to trigger and visualize such mechanical changes of individual nanoscopic objects. Here, ultrafast transmission electron microscopy (UTEM) is used to precisely probe the length changes of individual switchable nanoparticles induced thermally by nanosecond laser pulses. This allows revealing of the mechanisms of spin switching, leading to the macroscopic expansion of SCO materials. This study is conducted on individual pure SCO nanoparticles and SCO nanoparticles encapsulating gold nanorods that serve for plasmonic heating under laser pulses. Length changes are compared with time-resolved optical measurements performed on an assembly of these particles.
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Affiliation(s)
- Yaowei Hu
- Institut de Physique et Chimie des Matériaux, UMR 7504 CNRS, Université de Strasbourg, Strasbourg, F-67034, France
| | - Matthieu Picher
- Institut de Physique et Chimie des Matériaux, UMR 7504 CNRS, Université de Strasbourg, Strasbourg, F-67034, France
| | - Ngoc Minh Tran
- Universite de Bordeaux, CNRS, UMR 5798, LOMA, 358 Cours de la libération, Talence cedex, F-33405, France
| | - Marlène Palluel
- Institut de Chimie de la Matière Condensée de Bordeaux, CNRS, Université de Bordeaux, Bordeaux INP, UMR 5026, Pessac, F-33600, France
| | - Laurentiu Stoleriu
- Faculty of Physics, Alexandru Ioan Cuza University, Iasi, 700506, Romania
| | - Nathalie Daro
- Institut de Chimie de la Matière Condensée de Bordeaux, CNRS, Université de Bordeaux, Bordeaux INP, UMR 5026, Pessac, F-33600, France
| | - Stephane Mornet
- Institut de Chimie de la Matière Condensée de Bordeaux, CNRS, Université de Bordeaux, Bordeaux INP, UMR 5026, Pessac, F-33600, France
| | - Cristian Enachescu
- Faculty of Physics, Alexandru Ioan Cuza University, Iasi, 700506, Romania
| | - Eric Freysz
- Universite de Bordeaux, CNRS, UMR 5798, LOMA, 358 Cours de la libération, Talence cedex, F-33405, France
| | - Florian Banhart
- Institut de Physique et Chimie des Matériaux, UMR 7504 CNRS, Université de Strasbourg, Strasbourg, F-67034, France
| | - Guillaume Chastanet
- Institut de Chimie de la Matière Condensée de Bordeaux, CNRS, Université de Bordeaux, Bordeaux INP, UMR 5026, Pessac, F-33600, France
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Tong Y, Kelaï M, Bairagi K, Repain V, Lagoute J, Girard Y, Rousset S, Boillot ML, Mallah T, Enachescu C, Bellec A. Voltage-Induced Bistability of Single Spin-Crossover Molecules in a Two-Dimensional Monolayer. J Phys Chem Lett 2021; 12:11029-11034. [PMID: 34743521 DOI: 10.1021/acs.jpclett.1c03271] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Bistable spin-crossover molecules are particularly interesting for the development of innovative electronic and spintronic devices as they present two spin states that can be controlled by external stimuli. In this paper, we report the voltage-induced switching of the high spin/low spin electronic states of spin-crossover molecules self-assembled in dense 2D networks on Au(111) and Cu(111) by scanning tunneling microscopy at low temperature. On Au(111), voltage pulses lead to the nonlocal switching of the molecules from any─high or low─spin state to the other followed by a spontaneous relaxation toward their initial state within minutes. On the other hand, on Cu(111), single molecules can be addressed at will. They retain their new electronic configuration after a voltage pulse. The memory effect demonstrated on Cu(111) is due to an interplay between long-range intermolecular interaction and molecule/substrate coupling as confirmed by mechanoelastic simulations.
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Affiliation(s)
- Yongfeng Tong
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques (MPQ), CNRS-UMR7162, 75013, Paris, France
| | - Massine Kelaï
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques (MPQ), CNRS-UMR7162, 75013, Paris, France
| | - Kaushik Bairagi
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques (MPQ), CNRS-UMR7162, 75013, Paris, France
| | - Vincent Repain
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques (MPQ), CNRS-UMR7162, 75013, Paris, France
| | - Jérôme Lagoute
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques (MPQ), CNRS-UMR7162, 75013, Paris, France
| | - Yann Girard
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques (MPQ), CNRS-UMR7162, 75013, Paris, France
| | - Sylvie Rousset
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques (MPQ), CNRS-UMR7162, 75013, Paris, France
| | - Marie-Laure Boillot
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Saclay, CNRS, UMR 8182, 91405 Orsay Cedex, France
| | - Talal Mallah
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Saclay, CNRS, UMR 8182, 91405 Orsay Cedex, France
| | - Cristian Enachescu
- Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Iasi 700506, Romania
| | - Amandine Bellec
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques (MPQ), CNRS-UMR7162, 75013, Paris, France
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Kelai M, Repain V, Tauzin A, Li W, Girard Y, Lagoute J, Rousset S, Otero E, Sainctavit P, Arrio MA, Boillot ML, Mallah T, Enachescu C, Bellec A. Thermal Bistability of an Ultrathin Film of Iron(II) Spin-Crossover Molecules Directly Adsorbed on a Metal Surface. J Phys Chem Lett 2021; 12:6152-6158. [PMID: 34184899 DOI: 10.1021/acs.jpclett.1c01366] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Spin-crossover molecules are very attractive compounds to realize multifunctional spintronic devices. Understanding their properties when deposited on metals is therefore crucial for their future rational implementation as ultrathin films in such devices. Using X-ray absorption spectroscopy, we study the thermal transition of the spin-crossover compound FeII((3,5-(CH3)2Pz)3BH)2 from submonolayer to multilayers on a Cu(111) substrate. We determine how the residual fraction of high spin molecules at low temperature, as well as the bistability range and the temperature of switching, depends on the layer thickness. The most spectacular effect is the clear opening of a 35 ± 9 K thermal hysteresis loop for a 3.0 ± 0.7 monolayers thick film. To better understand the role played by the substrate and the dimensionality on the thermal bistability, we have performed Monte Carlo Arrhenius simulations in the framework of a mechanoelastic model that include a molecule-substrate interaction. This model reproduces well the main features observed experimentally and can predict how the spin-crossover transition is modified by the thickness and the substrate interaction.
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Affiliation(s)
- Massine Kelai
- Matériaux et Phénomènes Quantiques, Université de Paris, CNRS UMR 7162, 75013 Paris, France
| | - Vincent Repain
- Matériaux et Phénomènes Quantiques, Université de Paris, CNRS UMR 7162, 75013 Paris, France
| | - Arthur Tauzin
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Univ Paris Sud, Université Paris-Saclay, CNRS, UMR 8182, 91405 Orsay Cedex, France
| | - Weibin Li
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, CNRS UMR7590, Sorbonne Université, MNHN, 75252 Paris Cedex 5, France
| | - Yann Girard
- Matériaux et Phénomènes Quantiques, Université de Paris, CNRS UMR 7162, 75013 Paris, France
| | - Jérôme Lagoute
- Matériaux et Phénomènes Quantiques, Université de Paris, CNRS UMR 7162, 75013 Paris, France
| | - Sylvie Rousset
- Matériaux et Phénomènes Quantiques, Université de Paris, CNRS UMR 7162, 75013 Paris, France
| | - Edwige Otero
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, 91192 Gif sur Yvette, France
| | - Philippe Sainctavit
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, CNRS UMR7590, Sorbonne Université, MNHN, 75252 Paris Cedex 5, France
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, 91192 Gif sur Yvette, France
| | - Marie-Anne Arrio
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, CNRS UMR7590, Sorbonne Université, MNHN, 75252 Paris Cedex 5, France
| | - Marie-Laure Boillot
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Univ Paris Sud, Université Paris-Saclay, CNRS, UMR 8182, 91405 Orsay Cedex, France
| | - Talal Mallah
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Univ Paris Sud, Université Paris-Saclay, CNRS, UMR 8182, 91405 Orsay Cedex, France
| | - Cristian Enachescu
- Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Iasi, 700506, Romania
| | - Amandine Bellec
- Matériaux et Phénomènes Quantiques, Université de Paris, CNRS UMR 7162, 75013 Paris, France
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Lapierre A, Horn S, Créhange G, Enachescu C, Latorzeff I, Supiot S, Sargos P, Hennequin C, Chapet O. Radiothérapie stéréotaxique extracrânienne : quelle machine pour quelle indication ? Stéréotaxie prostatique. Cancer Radiother 2019; 23:651-657. [DOI: 10.1016/j.canrad.2019.06.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 06/26/2019] [Indexed: 10/26/2022]
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10
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Fourmental C, Mondal S, Banerjee R, Bellec A, Garreau Y, Coati A, Chacon C, Girard Y, Lagoute J, Rousset S, Boillot ML, Mallah T, Enachescu C, Barreteau C, Dappe YJ, Smogunov A, Narasimhan S, Repain V. Importance of Epitaxial Strain at a Spin-Crossover Molecule-Metal Interface. J Phys Chem Lett 2019; 10:4103-4109. [PMID: 31265299 DOI: 10.1021/acs.jpclett.9b01303] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Spin-crossover molecules are very appealing for use in multifunctional spintronic devices because of their ability to switch between high-spin and low-spin states with external stimuli such as voltage and light. In actual devices, the molecules are deposited on a substrate, which can modify their properties. However, surprisingly little is known about such molecule-substrate effects. Here we show for the first time, by grazing incidence X-ray diffraction, that an FeII spin-crossover molecular layer displays a well-defined epitaxial relationship with a metal substrate. Then we show, by both density functional calculations and a mechanoelastic model, that the resulting epitaxial strain and the related internal pressure can induce a partial spin conversion at low temperatures, which has indeed been observed experimentally. Our results emphasize the importance of substrate-induced spin state transitions and raise the possibility of exploiting them.
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Affiliation(s)
- Cynthia Fourmental
- Matériaux et Phénomènes Quantiques , Université de Paris, CNRS, UMR 7162 , 10 rue A. Domon et L. Duquet , 75013 Paris , France
| | - Sourav Mondal
- Theoretical Sciences Unit and School of Advanced Materials , Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur , Bangalore 560064 , India
| | - Rajdeep Banerjee
- Theoretical Sciences Unit and School of Advanced Materials , Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur , Bangalore 560064 , India
| | - Amandine Bellec
- Matériaux et Phénomènes Quantiques , Université de Paris, CNRS, UMR 7162 , 10 rue A. Domon et L. Duquet , 75013 Paris , France
| | - Yves Garreau
- Matériaux et Phénomènes Quantiques , Université de Paris, CNRS, UMR 7162 , 10 rue A. Domon et L. Duquet , 75013 Paris , France
- Synchrotron SOLEIL , L'Orme des Merisiers, Saint-Aubin , 91192 Gif sur Yvette , France
| | - Alessandro Coati
- Synchrotron SOLEIL , L'Orme des Merisiers, Saint-Aubin , 91192 Gif sur Yvette , France
| | - Cyril Chacon
- Matériaux et Phénomènes Quantiques , Université de Paris, CNRS, UMR 7162 , 10 rue A. Domon et L. Duquet , 75013 Paris , France
| | - Yann Girard
- Matériaux et Phénomènes Quantiques , Université de Paris, CNRS, UMR 7162 , 10 rue A. Domon et L. Duquet , 75013 Paris , France
| | - Jérôme Lagoute
- Matériaux et Phénomènes Quantiques , Université de Paris, CNRS, UMR 7162 , 10 rue A. Domon et L. Duquet , 75013 Paris , France
| | - Sylvie Rousset
- Matériaux et Phénomènes Quantiques , Université de Paris, CNRS, UMR 7162 , 10 rue A. Domon et L. Duquet , 75013 Paris , France
| | - Marie-Laure Boillot
- Institut de Chimie Moléculaire et des Matériaux d'Orsay , Univ Paris Sud, Université Paris-Saclay, CNRS, UMR 8182 , 91405 Orsay Cedex , France
| | - Talal Mallah
- Institut de Chimie Moléculaire et des Matériaux d'Orsay , Univ Paris Sud, Université Paris-Saclay, CNRS, UMR 8182 , 91405 Orsay Cedex , France
| | - Cristian Enachescu
- Faculty of Physics , Alexandru Ioan Cuza University of Iasi , Iasi 700506 , Romania
| | - Cyrille Barreteau
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay , 91191 Cedex Gif sur Yvette , France
| | - Yannick J Dappe
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay , 91191 Cedex Gif sur Yvette , France
| | - Alexander Smogunov
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay , 91191 Cedex Gif sur Yvette , France
| | - Shobhana Narasimhan
- Theoretical Sciences Unit and School of Advanced Materials , Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur , Bangalore 560064 , India
| | - Vincent Repain
- Matériaux et Phénomènes Quantiques , Université de Paris, CNRS, UMR 7162 , 10 rue A. Domon et L. Duquet , 75013 Paris , France
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11
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Bertoni R, Collet E, Cailleau H, Boillot ML, Tissot A, Laisney J, Enachescu C, Lorenc M. Temperature dependence of the cooperative out-of-equilibrium elastic switching in a spin-crossover material. Phys Chem Chem Phys 2019; 21:6606-6612. [DOI: 10.1039/c8cp07074a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We explore the key parameters that influence the efficiency of the cooperative low-spin to high-spin conversion through long range elastic intermolecular interactions during the so-called elastic step, triggered by instantaneous photo-induced conversion.
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Affiliation(s)
- Roman Bertoni
- Univ Rennes
- CNRS, IPR (Institut de Physique de Rennes) – UMR 6251
- F-35000 Rennes
- France
| | - Eric Collet
- Univ Rennes
- CNRS, IPR (Institut de Physique de Rennes) – UMR 6251
- F-35000 Rennes
- France
| | - Hervé Cailleau
- Univ Rennes
- CNRS, IPR (Institut de Physique de Rennes) – UMR 6251
- F-35000 Rennes
- France
| | - Marie-Laure Boillot
- Institut de Chimie Moléculaire et des Matériaux d’Orsay
- Univ. Paris Sud
- Université Paris-Saclay
- CNRS
- 91405 Orsay
| | - Antoine Tissot
- Institut de Chimie Moléculaire et des Matériaux d’Orsay
- Univ. Paris Sud
- Université Paris-Saclay
- CNRS
- 91405 Orsay
| | - Jérôme Laisney
- Institut de Chimie Moléculaire et des Matériaux d’Orsay
- Univ. Paris Sud
- Université Paris-Saclay
- CNRS
- 91405 Orsay
| | | | - Maciej Lorenc
- Univ Rennes
- CNRS, IPR (Institut de Physique de Rennes) – UMR 6251
- F-35000 Rennes
- France
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12
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Guenee L, Delgado T, Enachescu C, Tissot A, Hauser A, Besnard C. Evidencing size-dependent cooperative effects on spin cross-over nanoparticles of Hofmann type [Fe(pz)Pt(CN) 4] coordination polymers. Acta Crystallogr A Found Adv 2018. [DOI: 10.1107/s2053273318089246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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13
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Delgado T, Enachescu C, Tissot A, Guénée L, Hauser A, Besnard C. The influence of the sample dispersion on a solid surface in the thermal spin transition of [Fe(pz)Pt(CN)4] nanoparticles. Phys Chem Chem Phys 2018; 20:12493-12502. [DOI: 10.1039/c8cp00775f] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The dispersion on a Sapphire surface of [Fe(pz)Pt(CN)4], pz = pyrazine nanoparticles influences the thermal spin transition, as shown using magnetic, spectroscopic and diffraction data. This is explained within the framework of the mechanoelastic model.
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Affiliation(s)
- Teresa Delgado
- Départment de Chimie Physique
- Université de Genève
- CH-1211 Genève
- Switzerland
| | | | - Antoine Tissot
- Institut des Matériaux Poreux de Paris
- FRE 2000 CNRS
- Ecole Normale Supérieure
- Ecole Supérieure de Physique et de Chimie Industrielle de Paris
- PSL Research University
| | - Laure Guénée
- Laboratoire de Cristallographie
- Université de Genève
- CH-1211 Genève
- Switzerland
| | - Andreas Hauser
- Départment de Chimie Physique
- Université de Genève
- CH-1211 Genève
- Switzerland
| | - Céline Besnard
- Laboratoire de Cristallographie
- Université de Genève
- CH-1211 Genève
- Switzerland
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14
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Chapet O, Bin S, Fenoglietto P, Jalade P, Faix A, Ruffion A, Udrescu C, Enachescu C, Yossi S, Azria D. Prostate Hypofractionated Radiation Therapy (62 Gy at 3.1 Gy Per Fraction) With Injection of Hyaluronic Acid: Final Results of the RPAH1 Study. Int J Radiat Oncol Biol Phys 2016. [DOI: 10.1016/j.ijrobp.2016.06.1245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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15
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Samlali H, Udrescu C, Enachescu C, Yossi S, Lapierre A, Jalade P, Chapet O. Prospective Evaluation of a Specific Technique of Sexual Function Preservation in External Beam Radiation Therapy for Prostate Cancer. Int J Radiat Oncol Biol Phys 2016. [DOI: 10.1016/j.ijrobp.2016.06.1306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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16
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Arnaud-Coffin P, Yossi S, D’hombres A, Khounigere M, Youbi Z, Bennani Z, Enachescu C, Caraivan I. Carcinome neuroendocrine de Merkel : expérience du centre hospitalier universitaire Lyon-Sud. Cancer Radiother 2016. [DOI: 10.1016/j.canrad.2016.08.105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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17
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Selmaji I, Udrescu C, Brahmi T, Samlali H, Lapierre A, Enachescu C, Rouvière O, Ruffion A, Chapet O. Radiothérapie de rattrapage après prostatectomie radicale : intérêt d’une escalade de dose sur les récidives locales macroscopiques. Cancer Radiother 2016. [DOI: 10.1016/j.canrad.2016.08.063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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18
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Yossi S, Brahmi T, Enachescu C, Selmaji I, Lapierre A, Samlali H, Chapet O. [Management of neuroendocrine prostate carcinoma: Literature review]. Cancer Radiother 2016; 20:330-5. [PMID: 27340027 DOI: 10.1016/j.canrad.2016.02.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 02/02/2016] [Accepted: 02/24/2016] [Indexed: 10/21/2022]
Abstract
Neuroendocrine prostate carcinoma is a rare entity causing both diagnostic and therapeutic issues. There are basically four histological forms (adenocarcinoma with neuroendocrine differentiation, carcinoid tumors, small cell neuroendocrine carcinomas, large cell neuroendocrine carcinomas), which can be pure or mixed associated with prostatic carcinoma. There is no consensus on the management or the prognosis of these various tumor subtypes. We conducted a literature review aiming to determine the potential therapeutic implications.
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Affiliation(s)
- S Yossi
- Département de radiothérapie, CHU Lyon Sud, 195, chemin du Grand-Revoyet, 69495 Pierre-Bénite, France.
| | - T Brahmi
- Département de radiothérapie, CHU Lyon Sud, 195, chemin du Grand-Revoyet, 69495 Pierre-Bénite, France
| | - C Enachescu
- Département de radiothérapie, CHU Lyon Sud, 195, chemin du Grand-Revoyet, 69495 Pierre-Bénite, France
| | - I Selmaji
- Département de radiothérapie, CHU Lyon Sud, 195, chemin du Grand-Revoyet, 69495 Pierre-Bénite, France; Département de radiothérapie, CHU de Marrakech, Marrakech, Maroc
| | - A Lapierre
- Département de radiothérapie, CHU Lyon Sud, 195, chemin du Grand-Revoyet, 69495 Pierre-Bénite, France
| | - H Samlali
- Département de radiothérapie, CHU Lyon Sud, 195, chemin du Grand-Revoyet, 69495 Pierre-Bénite, France; Département de radiothérapie, CHU de Casablanca, Casablanca, Maroc
| | - O Chapet
- Département de radiothérapie, CHU Lyon Sud, 195, chemin du Grand-Revoyet, 69495 Pierre-Bénite, France
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19
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Yossi S, Brahmi T, Enachescu C, Selmaji I, Lapierre A, Samlali H, Chapet O. Prise en charge des carcinomes neuroendocrines de prostate : revue de la littérature. Cancer Radiother 2016. [DOI: 10.1016/j.canrad.2016.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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20
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Bertoni R, Lorenc M, Cailleau H, Tissot A, Laisney J, Boillot ML, Stoleriu L, Stancu A, Enachescu C, Collet E. Elastically driven cooperative response of a molecular material impacted by a laser pulse. Nat Mater 2016; 15:606-10. [PMID: 27019383 DOI: 10.1038/nmat4606] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 02/24/2016] [Indexed: 05/05/2023]
Abstract
Photoinduced phase transformations occur when a laser pulse impacts a material, thereby transforming its electronic and/or structural orders, consequently affecting the functionalities. The transient nature of photoinduced states has thus far severely limited the scope of applications. It is of paramount importance to explore whether structural feedback during the solid deformation has the capacity to amplify and stabilize photoinduced transformations. Contrary to coherent optical phonons, which have long been under scrutiny, coherently propagating cell deformations over acoustic timescales have not been explored to a similar degree, particularly with respect to cooperative elastic interactions. Herein we demonstrate, experimentally and theoretically, a self-amplified responsiveness in a spin-crossover material during its delayed volume expansion. The cooperative response at the material scale prevails above a threshold excitation, significantly extending the lifetime of photoinduced states. Such elastically driven cooperativity triggered by a light pulse offers an efficient route towards the generation and stabilization of photoinduced phases in many volume-changing materials.
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Affiliation(s)
- Roman Bertoni
- Université de Rennes 1, Institut de Physique de Rennes, UMR UR1-CNRS 6251, F-35000 Rennes, France
| | - Maciej Lorenc
- Université de Rennes 1, Institut de Physique de Rennes, UMR UR1-CNRS 6251, F-35000 Rennes, France
| | - Hervé Cailleau
- Université de Rennes 1, Institut de Physique de Rennes, UMR UR1-CNRS 6251, F-35000 Rennes, France
| | - Antoine Tissot
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris Sud, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Jérôme Laisney
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris Sud, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Marie-Laure Boillot
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris Sud, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Laurentiu Stoleriu
- Faculty of Physics, Alexandru Ioan Cuza University, 700506 Iasi, Romania
| | - Alexandru Stancu
- Faculty of Physics, Alexandru Ioan Cuza University, 700506 Iasi, Romania
| | - Cristian Enachescu
- Faculty of Physics, Alexandru Ioan Cuza University, 700506 Iasi, Romania
| | - Eric Collet
- Université de Rennes 1, Institut de Physique de Rennes, UMR UR1-CNRS 6251, F-35000 Rennes, France
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21
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Enachescu C, Hauser A. Study of switching in spin transition compounds within the mechanoelastic model with realistic parameters. Phys Chem Chem Phys 2016; 18:20591-9. [DOI: 10.1039/c6cp02806c] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Thermal hysteresis loop calculated using the Monte Carlo Metropolis method and snapshots of the system just before percolation, showing clusters of the same spin state molecules near corners. Variation of the compression of the connecting spring while a molecule i flips from the LS to the HS state.
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Affiliation(s)
| | - Andreas Hauser
- Département de chimie physique
- Université de Genève
- 1211 Genève 4
- Switzerland
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22
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Udrescu C, Shakir S, Enachescu C, Rouvière O, Arion S, Caraivan I, Chapet O. Stabilité des marqueurs d’or implantés dans une loge prostatique pour une radiothérapie de rattrapage. Cancer Radiother 2015. [DOI: 10.1016/j.canrad.2015.07.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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23
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Chakraborty P, Enachescu C, Humair A, Egger L, Delgado T, Tissot A, Guénée L, Besnard C, Bronisz R, Hauser A. Light-induced spin-state switching in the mixed crystal series of the 2D coordination network {[Zn1−xFex(bbtr)3](BF4)2}∞: optical spectroscopy and cooperative effects. Dalton Trans 2014; 43:17786-96. [DOI: 10.1039/c4dt01728e] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Strong cooperative interactions result in light-induced bistability between the high-spin and the low-spin state.
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Affiliation(s)
- Pradip Chakraborty
- Département de Chimie Physique
- Université de Genève
- 1211 Genève, Switzerland
| | | | - Arnaud Humair
- Département de Chimie Physique
- Université de Genève
- 1211 Genève, Switzerland
| | - Leo Egger
- Département de Chimie Physique
- Université de Genève
- 1211 Genève, Switzerland
| | - Teresa Delgado
- Département de Chimie Physique
- Université de Genève
- 1211 Genève, Switzerland
| | - Antoine Tissot
- Département de Chimie Physique
- Université de Genève
- 1211 Genève, Switzerland
| | - Laure Guénée
- Laboratoire de Crystallographie
- Université de Genève
- 1211 Genève, Switzerland
| | - Céline Besnard
- Laboratoire de Crystallographie
- Université de Genève
- 1211 Genève, Switzerland
| | - Robert Bronisz
- Faculty of Chemistry
- University of Wroclaw
- 50-383 Wroclaw, Poland
| | - Andreas Hauser
- Département de Chimie Physique
- Université de Genève
- 1211 Genève, Switzerland
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24
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Chapet O, Decullier E, Faix A, Ruffion A, Jalade P, Fenoglietto P, Enachescu C, Azria D. Hypofractionated Intensity Modulated Radiation Therapy With Injection of Hyaluronic Acid for Localized Prostate Cancer: Results of a Phase 2 study (RPAH1). Int J Radiat Oncol Biol Phys 2013. [DOI: 10.1016/j.ijrobp.2013.06.447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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25
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Shakir S, Udrescu C, Enachescu C, Jalade P, Rouviere O, Chapet O. Migration Evaluation of Gold Markers Implanted in a Prostate Bed for Salvage Focal Irradiation. Int J Radiat Oncol Biol Phys 2013. [DOI: 10.1016/j.ijrobp.2013.06.1011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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26
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Chapet O, Enachescu C, Lorchel F. [Pelvic irradiation in prostate cancer: what place for what volumes?]. Cancer Radiother 2013; 17:562-5. [PMID: 23993883 DOI: 10.1016/j.canrad.2013.07.133] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 07/03/2013] [Indexed: 10/26/2022]
Abstract
External beam radiotherapy alone is a standard treatment for prostate cancer. According to clinical, histological and biological characteristics of the tumour, lymph node irradiation can be done in combination with irradiation of the prostate. The completion of pelvic irradiation remains controversial and may cause complications by increasing volumes of irradiated healthy tissues. The accuracy of the delineation of lymph node becomes an important issue. This article proposes to take on the characteristics of the pelvic lymph node drainage of the prostate, to review the literature on pelvic irradiation and the definition of volumes to be irradiated.
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Affiliation(s)
- O Chapet
- Service de radiothérapie oncologie, centre hospitalier Lyon Sud, 165, chemin du Grand-Revoyet, 69495 Pierre-Bénite cedex, France.
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27
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Chakraborty P, Pillet S, Bendeif EE, Enachescu C, Bronisz R, Hauser A. Light-Induced Bistability in the 2 D Coordination Network {[Fe(bbtr)3][BF4]2}∞: Wavelength-Selective Addressing of Molecular Spin States. Chemistry 2013; 19:11418-28. [DOI: 10.1002/chem.201301257] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Indexed: 11/10/2022]
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28
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Chakraborty P, Enachescu C, Hauser A. Analysis of the Experimental Data for Pure and Diluted [Fe
x
Zn
1–
x
(bbtr)
3
](ClO
4
)
2
Spin‐Crossover Solids in the Framework of a Mechanoelastic Model. Eur J Inorg Chem 2013. [DOI: 10.1002/ejic.201201193] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Pradip Chakraborty
- Département de Chimie Physique, Université de Genève, 30, quai Ernest‐Ansermet, 1211 Genève, Switzerland, http://www.unige.ch/sciences/chifi/Hauser/
| | - Cristian Enachescu
- Faculty of Physics, Al. I. Cuza University, 700506 Iasi, Romania, http://www.phys.uaic.ro/cristian‐enachescu/
| | - Andreas Hauser
- Département de Chimie Physique, Université de Genève, 30, quai Ernest‐Ansermet, 1211 Genève, Switzerland, http://www.unige.ch/sciences/chifi/Hauser/
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29
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Elmorabit B, Touch S, Hatime M, Tanguy R, Diaz O, Wautot V, Enachescu C, Couraud S, Mornex F. La radiothérapie stéréotaxique pulmonaire n’altère pas la fonction respiratoire des patients. Expérience du centre hospitalier Lyon-sud. Cancer Radiother 2012. [DOI: 10.1016/j.canrad.2012.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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30
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Hatime M, Elmorabit B, Touch S, Merle P, Tanguy R, Diaz O, Wautot V, Enachescu C, Elkhoti Y, Mornex F. Critères de tolérance du parenchyme hépatique cirrhotique non tumoral à l’association chimioembolisation−irradiation : recommandations possibles. Cancer Radiother 2012. [DOI: 10.1016/j.canrad.2012.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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31
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Chakraborty P, Enachescu C, Walder C, Bronisz R, Hauser A. Thermal and Light-Induced Spin Switching Dynamics in the 2D Coordination Network of {[Zn1-xFex(bbtr)3](ClO4)2}∞: The Role of Cooperative Effects. Inorg Chem 2012; 51:9714-22. [DOI: 10.1021/ic301006c] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Pradip Chakraborty
- Département de Chimie Physique, Université de Genève, 30, quai Ernest-Ansermet,
CH-1211 Genève, Switzerland
| | | | - Christophe Walder
- Département de Chimie Physique, Université de Genève, 30, quai Ernest-Ansermet,
CH-1211 Genève, Switzerland
| | - Robert Bronisz
- Faculty
of Chemistry, University of Wroclaw, F.
Joliot-Curie 14, 50-383 Wroclaw, Poland
| | - Andreas Hauser
- Département de Chimie Physique, Université de Genève, 30, quai Ernest-Ansermet,
CH-1211 Genève, Switzerland
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32
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Tissot A, Enachescu C, Boillot ML. Control of the thermal hysteresis of the prototypal spin-transition FeII(phen)2(NCS)2 compound via the microcrystallites environment: experiments and mechanoelastic model. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm33865c] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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33
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Mornex F, Hatime M, Touch S, Elmorabit B, Pigne G, Enachescu C, Diaz O, Elkhoti Y. Radiotherapy of the pancreas: state of the art in 2012. Recent Results Cancer Res 2012; 196:89-103. [PMID: 23129368 DOI: 10.1007/978-3-642-31629-6_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Affiliation(s)
- F Mornex
- Radiation Oncology Department, Centre Hospitalier Lyon Sud, Université Claude Bernard, Lyon, France.
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Ferbinteanu M, Cimpoesu F, Gîrţu MA, Enachescu C, Tanase S. Structure and Magnetism in Fe–Gd Based Dinuclear and Chain Systems. The Interplay of Weak Exchange Coupling and Zero Field Splitting Effects. Inorg Chem 2011; 51:40-50. [DOI: 10.1021/ic1023289] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marilena Ferbinteanu
- University of Bucharest, Faculty of Chemistry,
Inorganic Chemistry Department, Dumbrava
Rosie 23, Bucharest 020462, Romania
| | - Fanica Cimpoesu
- Institute of Physical Chemistry, Splaiul Independentei 202, Bucharest 060021,
Romania
| | - Mihai A. Gîrţu
- Ovidius University of Constanţa, Department of Physics, Constanţa
900527, Romania
| | | | - Stefania Tanase
- Van’t Hoff Institute
of Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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35
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Padurariu L, Enachescu C, Mitoseriu L. Monte Carlo simulations for describing the ferroelectric-relaxor crossover in BaTiO₃-based solid solutions. J Phys Condens Matter 2011; 23:325901. [PMID: 21785183 DOI: 10.1088/0953-8984/23/32/325901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The properties induced by the M(4+) addition (M = Zr, Sn, Hf) in BaM(x)Ti(1-x)O(3) solid solutions have been described on the basis of a 2D Ising-like network and Monte Carlo calculations, in which BaMO(3) randomly distributed unit cells were considered as being non-ferroelectric. The polarization versus temperature dependences when increasing the M(4+) concentration (x) showed a continuous reduction of the remanent polarization and of the critical temperature corresponding to the ferroelectric-paraelectric transition and a modification from a first-order to a second-order phase transition with a broad temperature range for which the transition takes place, as commonly reported for relaxors. The model also describes the system's tendency to reduce the polar clusters' average size while increasing their stability in time at higher temperatures above the Curie range, when a ferroelectric-relaxor crossover is induced by increasing the substitution (x). The equilibrium micropolar states during the polarization reversal process while describing the P(E) loops were comparatively monitored for the ferroelectric (x = 0) and relaxor (x = 0.3) states. Polarization reversal in relaxor compositions proceeds by the growth of several nucleated domains (the 'labyrinthine domain pattern') instead of the large scale domain formation typical for the ferroelectric state. The spatial and temporal evolution of the polar clusters in BaM(x)Ti(1-x)O(3) solid solutions at various x has also been described by the correlation length and correlation time. As expected for the ferroelectric-relaxor crossover characterized by a progressive increasing degree of disorder, local fluctuations cause a reducing correlation time when the substitution degree increases, at a given temperature. The correlation time around the Curie temperature increases, reflecting the increasing stability in time of some polar nanoregions in relaxors in comparison with ferroelectrics, which was experimentally proved in various types of relaxors.
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Affiliation(s)
- Leontin Padurariu
- Department of Physics, Alexandru Ioan Cuza University, 11 Bv. Carol I, 700506 Iasi, Romania
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36
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Krivokapic I, Chakraborty P, Enachescu C, Bronisz R, Hauser A. Low-Spin→High-Spin Relaxation Dynamics in the Highly Diluted Spin-Crossover System [FexZn1−x(bbtr)3](ClO4)2. Inorg Chem 2011; 50:1856-61. [DOI: 10.1021/ic102269y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Itana Krivokapic
- Département de Chimie Physique, Université de Genève, 30 Quai Ernest-Ansermet, CH-1211 Genève 4, Switzerland
| | - Pradip Chakraborty
- Département de Chimie Physique, Université de Genève, 30 Quai Ernest-Ansermet, CH-1211 Genève 4, Switzerland
| | - Cristian Enachescu
- Department of Physics, Alexandru Ioan Cuza University, Blvd. Carol I, nr. 11, Iasi, Romania
| | - Robert Bronisz
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, Pl-50-383 Wrocław, Poland
| | - Andreas Hauser
- Département de Chimie Physique, Université de Genève, 30 Quai Ernest-Ansermet, CH-1211 Genève 4, Switzerland
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37
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Krivokapic I, Chakraborty P, Bronisz R, Enachescu C, Hauser A. Riesenvariation der Geschwindigkeitskonstante des Singulett-Quintett-Intersystem-Crossings in einem Eisen(II)-high-spin-Komplex als Funktion der Temperatur. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201004500] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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38
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Rotaru A, Dîrtu MM, Enachescu C, Tanasa R, Linares J, Stancu A, Garcia Y. Calorimetric measurements of diluted spin crossover complexes [FexM1−x(btr)2(NCS)2]·H2O with MII=Zn and Ni. Polyhedron 2009. [DOI: 10.1016/j.poly.2009.04.046] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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39
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Enachescu C, Stoleriu L, Stancu A, Hauser A. Model for elastic relaxation phenomena in finite 2D hexagonal molecular lattices. Phys Rev Lett 2009; 102:257204. [PMID: 19659117 DOI: 10.1103/physrevlett.102.257204] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Indexed: 05/28/2023]
Abstract
The relaxation in a spin transition compound is modeled on the basis of molecules interacting by the way of connecting springs and situated in a bidimensional open boundary hexagonal lattice. The switch of individual molecules is randomly checked using a standard Monte Carlo procedure. The switching probability depends on the energy gap between the two states in the absence of interactions and on the elongations of the nearest springs. The main characteristics of the experimental relaxation curves are reproduced and clustering and nucleation phenomena are detected.
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Mishra V, Mishra H, Mukherjee R, Codjovi E, Linarès J, Létard JF, Desplanches C, Baldé C, Enachescu C, Varret F. Spin-transition in [FeII(L5)2][ClO4]2 [L5 = 2-[3-(2′-pyridyl)pyrazol-1-ylmethyl](1-methylimidazole)]: a further example of coexistence of features typical for disorder and cooperativity. Dalton Trans 2009:7462-72. [DOI: 10.1039/b901397k] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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41
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Krivokapic I, Enachescu C, Bronisz R, Hauser A. Spin transition and relaxation dynamics coupled to a crystallographic phase transition in a polymeric iron(II) spin-crossover system. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.02.088] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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42
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Krivokapic I, Zerara M, Daku ML, Vargas A, Enachescu C, Ambrus C, Tregenna-Piggott P, Amstutz N, Krausz E, Hauser A. Spin-crossover in cobalt(II) imine complexes. Coord Chem Rev 2007. [DOI: 10.1016/j.ccr.2006.05.006] [Citation(s) in RCA: 198] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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43
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Hauser A, Enachescu C, Daku ML, Vargas A, Amstutz N. Low-temperature lifetimes of metastable high-spin states in spin-crossover and in low-spin iron(II) compounds: The rule and exceptions to the rule. Coord Chem Rev 2006. [DOI: 10.1016/j.ccr.2005.12.006] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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44
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Enachescu C, Hauser A, Girerd JJ, Boillot ML. Photoexcitation and Relaxation Dynamics of Catecholato–Iron(III) Spin-Crossover Complexes. Chemphyschem 2006; 7:1127-35. [PMID: 16586423 DOI: 10.1002/cphc.200500671] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The photophysical properties of the ferric catecholate spin-crossover compounds [(TPA)Fe(R-Cat)]X (TPA=tris(2-pyridylmethyl)amine; X=PF(6) (-), BPh(4) (-); R-Cat=catecholate dianion substituted by R=NO(2), Cl, or H) are investigated in the solid state. The catecholate-to-iron(III) charge-transfer bands are sensitive both to the spin state of the metal ion and the charge-transfer interactions associated with the different catecholate substituents. Vibronic progressions are identified in the near-infrared (NIR) absorption of the low-spin species. Evidence for a low-temperature photoexcitation process is provided. The relaxation dynamics between 10 and 100 K indicate a pure tunneling process below approximately 40 K, and a thermally activated region at higher temperatures. The relaxation rate constants in the tunneling regime at low temperature, k(HL)(T-->0), vary in the range from 0.58 to 8.84 s(-1). These values are in qualitative agreement with the inverse energy-gap law and with structural parameters. A comparison with ferrous spin-crossover complexes shows that the high-spin to low-spin relaxation is generally faster for ferric complexes, owing to the smaller bond length changes for the latter. However, in the present case the corresponding rate constants are smaller than expected based on the single configurational coordinate model. This is attributed to the combined influence of the electronic configuration and the molecular geometry.
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Affiliation(s)
- Cristian Enachescu
- Faculty of Physics, Department of Solid State and Theoretical Physics, Alexandru Ioan Cuza University, 700506 Iasi, Romania
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45
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Enachescu C, Varret F, Codjovi E, Linarès J, Floquet S, Manikandan P, Manoharan PT. Photoexcitation and Relaxation Properties of a Spin-Crossover Solid in the Case of a Stable High-Spin State. J Phys Chem B 2006; 110:5883-8. [PMID: 16553394 DOI: 10.1021/jp054149e] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The molecular solid [Fe(II)L(2)](ClO(4))(2).CH(3)CN where L is 2,6-bis(3,5-dimethylpyrazol-1-ylmethyl)pyridine provides a stable high-spin (HS) state at low temperature. Photoexcitation and subsequent relaxation have been studied using light-induced excited state spin trapping [LIESST(H --> L)] in the 700-850 nm range, determination of T(LIESST), relaxation curves at different temperatures, and temperature dependence of the light-induced spin equilibrium under constant irradiation. The measured photoinduced population of the metastable low-spin (LS) state (<30%) was drastically limited by the concomitant L --> H photoprocess. The absence of static light-induced thermal hysteresis and the stretched exponential shape of the relaxation curves respectively revealed the absence of sizable interactions and a large spreading of the activation energies attributed to the ligand flexibility. The whole data set has been simulated using a linear rate equation, with a simplified correction for the bulk extinction of light in the powder sample.
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Affiliation(s)
- Cristian Enachescu
- Laboratoire de Magnétisme et d'Optique, CNRS-Université de Versailles, 78035 Versailles, France
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Gawali-Salunke S, Varret F, Maurin I, Enachescu C, Malarova M, Boukheddaden K, Codjovi E, Tokoro H, Ohkoshi S, Hashimoto K. Magnetic and Mössbauer Investigation of the Photomagnetic Prussian Blue Analogue Na0.32Co[Fe(CN)6]0.74·3.4H2O: Cooperative Relaxation of the Thermally Quenched State. J Phys Chem B 2005; 109:8251-6. [PMID: 16851964 DOI: 10.1021/jp044739x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thanks to thermal quenching we investigated the relaxation of the metastable state of Na(0.32)Co[Fe(CN)6](0.74).3.4H2O at low temperature. A self-accelerated process has been observed in agreement with the cooperative character of the system, responsible for the large thermal hysteresis of the charge-transfer-induced spin transition. The mean-field analysis of the relaxation is discussed with respect to the equilibrium properties. A sizable deviation from mean-field behavior is observed at the beginning of the relaxation process, which might be attributed to a preliminary structural relaxation of the quenched state.
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Affiliation(s)
- S Gawali-Salunke
- Laboratoire de Magnétisme et d'Optique, CNRS-Université de Versailles Saint Quentin, 45, Avenue des Etats-Unis, 78035 Versailles Cedex, France
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Niel V, Thompson AL, Goeta AE, Enachescu C, Hauser A, Galet A, Muñoz MC, Real JA. Thermal- and Photoinduced Spin-State Switching in an Unprecedented Three-Dimensional Bimetallic Coordination Polymer. Chemistry 2005; 11:2047-60. [PMID: 15693059 DOI: 10.1002/chem.200400930] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The compound {Fe(pmd)[Ag(CN)2][Ag2(CN)3]} (pmd=pyrimidine) was synthesized and characterized. Magnetic, calorimetric and single crystal visible spectroscopic studies demonstrate the occurrence of a two-step high-spin (HS) right arrow over left arrow low-spin (LS) transition. The critical temperatures are T(c1)=185 and T(c2)=148 K. Each step involves approximately 50 % of the iron centers, with the low-temperature step showing a hysteresis of 2.5 K. The enthalpy and entropy variations associated with the two steps are DeltaH(1)=3.6+/-0.4 kJ mol(-1) and DeltaS(1)=19.5+/-3 J K(-1) mol(-1); DeltaH(2)=4.8+/-0.4 kJ mol(-1) and DeltaS(2)=33.5+/-3 J K(-1) mol(-1). Photomagnetic and visible spectroscopy experiments show that below 50 K, where the LS state is the thermodynamically stable state, the compound can be switched quantitatively to the HS state using green-red light (550-650 nm). HS-to-LS relaxation experiments in the dark at temperatures between 15 and 55 K show that the relaxation takes place via a two-step cooperative process, which was analyzed in the context of the mean field theory. The crystal structure has been studied at 290, 220, 170, 90 and 30 K together with 30 K after irradiation. The compound adopts monoclinic symmetry (P2(1)/c, Z=16) at all temperatures. There are five [FeN6] pseudo-octahedral sites linked by pmd, [Ag(CN)2]- and [Ag2(CN)3]- bridging ligands to form an unprecedented three-dimensional (6,6) topology. The structural analysis allows for an understanding of the microscopic mechanism of the two-step behavior of the thermally induced spin transition as well as the corresponding relaxation of the photoexcited compound based on the individual changes of the five sites. Synergy between metallophilic interactions and the spin transition is also shown by the variation of the AgAg distances. Correlations between the variation of the unit-cell volume and the change of AgAg interactions within each step with the asymmetric change of the anomalous heat capacity have also been inferred.
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Affiliation(s)
- Virginie Niel
- Institut de Ciencia Molecular/Departament de Química Inorgánica, Universitat de València, Doctor Moliner 50, 46100 Burjassot, Spain
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Enachescu C, Linares J, Varret F, Boukheddaden K, Codjovi E, Salunke SG, Mukherjee R. Nonexponential Relaxation of the Metastable State of the Spin-Crossover System [Fe(L)2](ClO4)2·H2O [L = 2,6-Bis(pyrazol-1-ylmethyl)pyridine]. Inorg Chem 2004; 43:4880-8. [PMID: 15285662 DOI: 10.1021/ic049938+] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The relaxation of the metastable state of the spin-crossover compound [Fe(L)(2)](ClO(4))(2).H(2)O, with L = 2,6-bis(pyrazol-1-ylmethyl)pyridine, populated by the LIESST (light induced excited spin state trapping) effect, has been investigated by magnetic measurements. The time dependence of the relaxation curve at several temperatures, starting from different initial states, is in the shape of stretched exponentials, and the thermal variation of the photostationary state under constant photoexcitation is progressive and reversible. These features are satisfactorily modeled by considering noninteracting two-level systems with a distribution of activation energies. A suggested origin for the distribution is the conformational flexibility of the nonplanar heterocyclic ligands. The effect of the intensity distribution during the LIESST process is also accounted for in a simple way.
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Affiliation(s)
- Cristian Enachescu
- Laboratoire de Magnétisme et d'Optique, CNRS-Université de Versailles, 78035 Versailles, France
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Varret F, Boukheddaden K, Codjovi E, Enachescu C, Linarès J. On the Competition Between Relaxation and Photoexcitations in Spin Crossover Solids under Continuous Irradiation. Top Curr Chem (Cham) 2004. [DOI: 10.1007/b95417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
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50
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Linares J, Enachescu C, Boukheddaden K, Varret F. Monte Carlo entropic sampling applied to spin crossover solids: the squareness of the thermal hysteresis loop. Polyhedron 2003. [DOI: 10.1016/s0277-5387(03)00219-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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