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Compressibility and Structural Transformations of Aluminogermanate Imogolite Nanotubes under Hydrostatic Pressure. Inorg Chem 2023; 62:957-966. [PMID: 36595652 DOI: 10.1021/acs.inorgchem.2c03798] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We present in situ pressure experiments on aluminogermanate nanotubes studied by X-ray scattering and absorption spectroscopy measurements. Structural transformations under hydrostatic pressure below 10 GPa are investigated as a function of the morphology, organization, or functionalization of the nanotubes. Radial deformations, ovalization for isolated nanotubes, and hexagonalization when they are bundled are evidenced. Radial collapse of single-walled nanotubes is shown to occur, in contrast to the double-walled nanotubes. The effect of the transmitting pressure medium used on the collapse onset pressure value is demonstrated. Axial Young's moduli are determined for isolated (400 GPa) and bundled (600 GPa) single-walled nanotubes, double-walled nanotubes (440 GPa), and methylated single-walled nanotubes (200 GPa).
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2
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Profile of an “at cutting edge” pathology laboratory for pathological human deposits: from nanometer to in vivo scale analysis on large scale facilities. CR CHIM 2022. [DOI: 10.5802/crchim.199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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3
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Whitlockite structures in kidney stones indicate infectious origin: a scanning electron microscopy and Synchrotron Radiation investigation. CR CHIM 2022. [DOI: 10.5802/crchim.80] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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4
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Powder diffraction on beamline CRISTAL: faster measurements and automation. ACTA CRYSTALLOGRAPHICA SECTION A FOUNDATIONS AND ADVANCES 2022. [DOI: 10.1107/s2053273322089999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
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5
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SOLEIL ongoing development using industrial robots for beamline automation. ACTA CRYSTALLOGRAPHICA SECTION A FOUNDATIONS AND ADVANCES 2022. [DOI: 10.1107/s2053273322090167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
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Uranium speciation control by uranyl sulfate and phosphate in tailings subject to a Sahelian climate, Cominak, Niger. CHEMOSPHERE 2022; 287:132139. [PMID: 34509019 DOI: 10.1016/j.chemosphere.2021.132139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/31/2021] [Accepted: 08/31/2021] [Indexed: 06/13/2023]
Abstract
Long-term uranium mobility in tailings is an environmental management issue. The present study focuses on two U-enriched layers, surficial and buried 14.5 m, of the tailings pile of Cominak, Niger. The acidic and oxidizing conditions of the tailings pile combined with evapotranspiration cycles related to the Sahelian climate control U speciation. Uraninite, brannerite, and moluranite as well as uranophane are relict U phases. EXAFS spectroscopy, HR-XRD, and SEM/WDS highlight the major role of uranyl sulfate groups in uranium speciation. Uranyl phosphate neoformation in the buried layer (paleolayer) acts as an efficient trap for uranium.
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Steric and electronic effects of ligand substitution on redox-active Fe 4S 4-based coordination polymers. Dalton Trans 2021; 50:10798-10805. [PMID: 34287442 DOI: 10.1039/d1dt01652k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
One of the notable advantages of molecular materials is the ability to precisely tune structure, properties, and function via molecular substitutions. While many studies have demonstrated this principle with classic carboxylate-based coordination polymers, there are comparatively fewer examples where systematic changes to sulfur-based coordination polymers have been investigated. Here we present such a study on 1D coordination chains of redox-active Fe4S4 clusters linked by methylated 1,4-benzene-dithiolates. A series of new Fe4S4-based coordination polymers were synthesized with either 2,5-dimethyl-1,4-benzenedithiol (DMBDT) or 2,3,5,6-tetramethyl-1,4-benzenedithiol (TMBDT). The structures of these compounds have been characterized based on synchrotron X-ray powder diffraction while their chemical and physical properties have been characterized by techniques including X-ray photoelectron spectroscopy, cyclic voltammetry and UV-visible spectroscopy. Methylation results in the general trend of increasing electron-richness in the series, but the tetramethyl version exhibits unexpected properties arising from steric constraints. All these results highlight how substitutions on organic linkers can modulate electronic factors to fine-tune the electronic structures of metal-organic materials.
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Site Occupancy Determination in Th 2Zn 17- and TbCu 7-types Sm 2Fe 17-xCo x Compounds using Synchrotron Resonant Diffraction. Inorg Chem 2021; 60:1533-1541. [PMID: 33439654 DOI: 10.1021/acs.inorgchem.0c02884] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sm2Fe17 compounds are high-performance permanent magnets. Cobalt substitution allows us to further improve their magnetic properties. Depending on the thermal treatment, cobalt-substituted compounds can be synthesized either in the TbCu7 (disordered) or in the Th2Zn17 (ordered) structure type. Rietveld refinement of the number of transition metal dumbbells replacing rare-earth atoms from synchrotron powder diffraction data shows that the TbCu7 disordered structure has the same composition as the ordered one (a transition metal-to-rare earth ratio of 8.5). Then, cobalt site occupancies have been determined in both structures using synchrotron resonant (anomalous) diffraction. Cobalt is found to be absent from the dumbbell sites. The diffraction results are confirmed by Mössbauer spectroscopy.
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The structure of kaliophilite KAlSiO 4, a long-lasting crystallographic problem. IUCRJ 2020; 7:1070-1083. [PMID: 33209318 PMCID: PMC7642771 DOI: 10.1107/s2052252520012270] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 09/04/2020] [Indexed: 05/04/2023]
Abstract
Kaliophilite is a feldspathoid mineral found in two Italian magmatic provinces and represents one of the 12 known phases with composition close to KAlSiO4. Despite its apparently simple formula, the structure of this mineral revealed extremely complex and resisted structure solution for more than a century. Samples from the Vesuvius-Monte Somma and Alban Hills volcanic areas were analyzed through a multi-technique approach, and finally the crystal structure of kaliophilite was solved using 3D electron diffraction and refined against X-ray diffraction data of a twinned crystal. Results were also ascertained by the Rietveld method using synchrotron powder intensities. It was found that kaliophilite crystallizes in space group P3 with unit-cell parameters a = 27.0597 (16), c = 8.5587 (6) Å, V = 5427.3 (7) Å3 and Z = 54. The kaliophilite framework is a variant of the tridymite topology, with alternating SiO4 and AlO4 tetrahedra forming sheets of six-membered rings (63 nets), which are connected along [001] by sharing the apical oxygen atoms. Considering the up (U) and down (D) orientations of the linking vertex, kaliophilite is the first framework that contains three different ring topologies: nine (1-3-5) (UDUDUD) rings, six (1-2-3) (UUUDDD) rings and twelve (1-2-4) (UUDUDD) rings. This results in a relatively open (19.9 tetrahedra nm-3) channel system with multiple connections between the double six-ring cavities. Such a framework requires a surprisingly large unit cell, 27 times larger than the cell of kalsilite, the simplest phase with the same composition. The occurrence of some Na for K substitution (3-10%) may be related to the characteristic structural features of kaliophilite. Micro-twinning, pseudo-symmetries and anisotropic hkl-dependent peak broadening were also detected, and they may account for the elusive character of the kaliophilite crystal structure.
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Abstract
Porphyrin nanorods were prepared by ion-association between free-base meso 5,10,15,20-tetrakis-(4-[Formula: see text]-methylpyridinium)porphyrin cations and tetraphenylborate anions. The nanorods have variable lengths (up to a few micrometers long) and diameters ([Formula: see text]50–500 nm). Their structure at the molecular level was elucidated by combining multinuclear solid state NMR spectroscopy, synchrotron X-ray powder diffraction and DFT calculations.
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11
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Advances in the synthesis and structure of α-canaphite: a multitool and multiscale study. CrystEngComm 2020. [DOI: 10.1039/d0ce00132e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pure α-canaphite is synthesized and thoroughly characterized; its hydrated layered structure is now fully solved by combining experimental and modeling data.
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Correction: Modulation of the mechanical energy storage performance of the MIL-47(V IV) metal organic framework by ligand functionalization. Dalton Trans 2019; 48:2823. [DOI: 10.1039/c9dt90029b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Correction for ‘Modulation of the mechanical energy storage performance of the MIL-47(VIV) metal organic framework by ligand functionalization’ by Pascal G. Yot et al., Dalton Trans., 2019, DOI: 10.1039/c8dt04214d.
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A highly conductive nanostructured PEDOT polymer confined into the mesoporous MIL-100(Fe). Dalton Trans 2019; 48:9807-9817. [DOI: 10.1039/c9dt00917e] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A novel nanostructured conducting polymer@MOF composite has demonstrated an enhanced conductivity and a reversible and cyclable electrochromic switching.
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Modulation of the mechanical energy storage performance of the MIL-47(V IV) metal organic framework by ligand functionalization. Dalton Trans 2018; 48:1656-1661. [PMID: 30560260 DOI: 10.1039/c8dt04214d] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The functionalization of the metal-organic framework MIL-47(VIV) with ligands bearing bulky functional groups (-Br or -CF3) has been envisaged as a possible route to enhance the mechanical energy storage performances of this family of hybrid porous materials. This exploratory work was carried out by coupling advanced experimental techniques (mercury intrusion and X-ray powder diffraction) supported by density functional theory calculations. MIL-47(VIV)-BDC-CF3 was demonstrated to be one of the most promising porous materials for mechanical energy-related applications with performance in terms of work energy which surpasses that of any porous solids reported so far.
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New Lamellar Silver Thiolate Coordination Polymers with Tunable Photoluminescence Energies by Metal Substitution. Inorg Chem 2018; 58:99-105. [PMID: 30525528 DOI: 10.1021/acs.inorgchem.8b01257] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The structures of two lamellar silver thiolate coordination polymers [Ag( p-SPhCO2H)] n (1) and [Ag( p-SPhCO2Me)] n (2) are described for the first time. Their inorganic part is composed of distorted Ag3S3 honeycomb networks separated by noninterpenetrated thiolate ligands. The main difference between the two compounds arises from dimeric hydrogen bonds present for the carboxylic acids. Indepth photophysical studies show that the silver thiolates exhibit multiemission properties, implying luminescence thermochromism. More interestingly, the synthesis of a heterometallic lamellar compound, [Ag0.85Cu0.15( p-SPhCO2H)] n (3), allows to obtain mixed metal thiolate coordination polymers and to tune the photophysical properties with the excitation wavelengths from a green vibronic luminescence to a single red emission band.
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Insights into water–rock interactions in meteorites from diffraction tomography. ACTA CRYSTALLOGRAPHICA SECTION A FOUNDATIONS AND ADVANCES 2018. [DOI: 10.1107/s2053273318094482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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17
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Sub-na and sub-ps time-resolved diffraction at CRISTAL beamline – SOLEIL synchrotron. Acta Crystallogr A Found Adv 2018. [DOI: 10.1107/s2053273318089180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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18
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Commissioning of a multi-beamline femtoslicing facility at SOLEIL. JOURNAL OF SYNCHROTRON RADIATION 2018; 25:385-398. [PMID: 29488917 DOI: 10.1107/s1600577518000863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 11/21/2017] [Indexed: 06/08/2023]
Abstract
The investigation of ultrafast dynamics, taking place on the few to sub-picosecond time scale, is today a very active research area pursued in a variety of scientific domains. With the recent advent of X-ray free-electron lasers (XFELs), providing very intense X-ray pulses of duration as short as a few femtoseconds, this research field has gained further momentum. As a consequence, the demand for access strongly exceeds the capacity of the very few XFEL facilities existing worldwide. This situation motivates the development of alternative sub-picosecond pulsed X-ray sources among which femtoslicing facilities at synchrotron radiation storage rings are standing out due to their tunability over an extended photon energy range and their high stability. Following the success of the femtoslicing installations at ALS, BESSY-II, SLS and UVSOR, SOLEIL decided to implement a femtoslicing facility. Several challenges were faced, including operation at the highest electron beam energy ever, and achievement of slice separation exclusively with the natural dispersion function of the storage ring. SOLEIL's setup also enables, for the first time, delivering sub-picosecond pulses simultaneously to several beamlines. This last feature enlarges the experimental capabilities of the facility, which covers the soft and hard X-ray photon energy range. In this paper, the commissioning of this original femtoslicing facility is reported. Furthermore, it is shown that the slicing-induced THz signal can be used to derive a quantitative estimate for the degree of energy exchange between the femtosecond infrared laser pulse and the circulating electron bunch.
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19
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Trirutiles as potential multiferroics: the case of Mn 2TeO 6. Acta Crystallogr A Found Adv 2017. [DOI: 10.1107/s2053273317092014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Structural Study of a Doubly Ordered Perovskite Family NaLnCoWO6 (Ln = Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb): Hybrid Improper Ferroelectricity in Nine New Members. Inorg Chem 2017; 56:8478-8489. [DOI: 10.1021/acs.inorgchem.7b01218] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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21
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In pursuit of the rhabdophane crystal structure: from the hydrated monoclinic LnPO 4 .0.667H 2 O to the hexagonal LnPO 4 (Ln = Nd, Sm, Gd, Eu and Dy). J SOLID STATE CHEM 2017. [DOI: 10.1016/j.jssc.2017.03.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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22
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Investigating the Case of Titanium(IV) Carboxyphenolate Photoactive Coordination Polymers. Inorg Chem 2016; 55:7192-9. [DOI: 10.1021/acs.inorgchem.6b01060] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Structure of the calcium pyrophosphate monohydrate phase (Ca2P2O7·H2O): towards understanding the dehydration process in calcium pyrophosphate hydrates. ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY 2014; 70:862-6. [PMID: 25186358 DOI: 10.1107/s2053229614017446] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 07/29/2014] [Indexed: 12/28/2022]
Abstract
Calcium pyrophosphate hydrate (CPP, Ca(2)P(2)O(7) · nH2O) and calcium orthophosphate compounds (including apatite, octacalcium phosphate etc.) are among the most prevalent pathological calcifications in joints. Even though only two dihydrated forms of CPP (CPPD) have been detected in vivo (monoclinic and triclinic CPPD), investigations of other hydrated forms such as tetrahydrated or amorphous CPP are relevant to a further understanding of the physicochemistry of those phases of biological interest. The synthesis of single crystals of calcium pyrophosphate monohydrate (CPPM; Ca(2)P(2)O(7) · H2O) by diffusion in silica gel at ambient temperature and the structural analysis of this phase are reported in this paper. Complementarily, data from synchrotron X-ray diffraction on a CPPM powder sample have been fitted to the crystal parameters. Finally, the relationship between the resolved structure for the CPPM phase and the structure of the tetrahydrated calcium pyrophosphate β phase (CPPT-β) is discussed.
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25
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Abnormal operando structural behavior of sodium battery material: Influence of dynamic on phase diagram of NaxFePO4. Electrochem commun 2014. [DOI: 10.1016/j.elecom.2013.11.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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26
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High-pressure crystallography on the CRISTAL beamline at SOLEIL synchrotron. Acta Crystallogr A 2012. [DOI: 10.1107/s0108767312096481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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27
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Estimation of iron valencies of Prussian blue pigment by anomalous X-ray diffraction. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311097297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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28
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High-Throughput Aided Synthesis of the Porous Metal−Organic Framework-Type Aluminum Pyromellitate, MIL-121, with Extra Carboxylic Acid Functionalization. Inorg Chem 2010; 49:9852-62. [DOI: 10.1021/ic101128w] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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29
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[Synchrotron radiation techniques for structural characterisation of biological entities: an example with renal stone analysis]. Ann Biol Clin (Paris) 2006; 64:125-39. [PMID: 16556523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Accepted: 01/12/2006] [Indexed: 05/08/2023]
Abstract
This paper describes the opportunities given by the synchrotron radiation techniques regarding the structural characterisation of biological entities. After a short recall on the characteristics of the synchrotron radiation, are described the experimental devices based on fluorescence X, wide angle X-ray scattering and X-ray absorption spectroscopy, which may applied for biological samples, especially in the field of stone analysis. Recent progresses in medical research using synchrotron radiation will be also discussed.
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Structures in Mo-Ru-Si system by powder and anomal X-ray diffraction. Acta Crystallogr A 2005. [DOI: 10.1107/s0108767305093268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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31
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Structural aspects of the metal–insulator transition in BaVS 3. Acta Crystallogr A 2004. [DOI: 10.1107/s0108767304095601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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32
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X-ray diffraction investigation of the relationship between strains and metal-insulator transition in NdNiO3 thin films. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s1463-0184(02)00043-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Conformations of the nonbonded and the coordinated ligand nonamethylimidodiphosphoramide (NIPA) in the solid state and in solution. X-ray structure determinations, NMR study, and theoretical calculations on the NIPA molecule and the complex [UO2(NIPA)2C2H5OH](ClO4)2. J Am Chem Soc 2002. [DOI: 10.1021/ja00333a037] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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35
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An in Situ Study Using Anomalous Wide-Angle X-ray Scattering and X-ray Absorption Spectroscopy of the Catalytic System ZnAl2O4 Supported on Alumina. J Phys Chem B 2000. [DOI: 10.1021/jp9937959] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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36
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Cationic Order and Structure of [Zn−Cr−Cl] and [Cu−Cr−Cl] Layered Double Hydroxides: A XRD and EXAFS Study. J Phys Chem B 2000. [DOI: 10.1021/jp0000735] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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37
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Aspects complémentaires entre la spectroscopie d'absorption X et la diffraction anomale dans le cas d'entités de taille nanométrique supportés sur un oxyde léger : agrégats métalliques et oxyde de type spinelle. ACTA ACUST UNITED AC 1998. [DOI: 10.1051/jp4:1998533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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38
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Use of Anomalous Diffraction, DAFS and DANES Techniques for Site-Selective Spectroscopy of Complex Oxides. JOURNAL OF SYNCHROTRON RADIATION 1995; 2:236-44. [PMID: 16714822 DOI: 10.1107/s0909049595007886] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The diffraction anomalous fine structure (DAFS) technique is applied to highly absorbing ;real' crystals of arbitrary shape containing several heavy atoms. A multiwavelength refinement procedure of DAFS signals is demonstrated on two different oxides, BaPt(4+)(1-2x)(Pt( 2+)(1-y)Ba( 2+)(y) )(x)O(3-3x) with x = 0.25, y approximately 0 and BaZnFe(6)O(11), which have complex crystallographic structures. In these compounds, anomalous scatterers are located in different crystallographic sites and thus a multiwavelength refinement is necessary to separate out the site-selective information. An accurate absorption correction procedure for small, highly absorbing single crystals necessary for the DAFS analysis of this kind of samples is also presented.
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Structural Determination and Magnetic Properties of a New Orthorhombic Chromium Seleno Stannate, Cr2Sn3Se7. J SOLID STATE CHEM 1995. [DOI: 10.1006/jssc.1995.1116] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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40
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Neutron-diffraction study of icosahedral Al-Cu-Fe single quasicrystals. PHYSICAL REVIEW. B, CONDENSED MATTER 1991; 44:2071-2084. [PMID: 9999756 DOI: 10.1103/physrevb.44.2071] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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41
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The Gram-Charlier and multipole expansions in accurate X-ray diffraction studies: can they be distinguished? Acta Crystallogr A 1988; 44 ( Pt 3):336-42. [PMID: 3272150 DOI: 10.1107/s0108767387012558] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The Gram-Charlier temperature factor formalism has been applied to a set of accurate low-temperature data on bis(pyridine)(meso-tetraphenylporphinato)iron(II), and to a theoretical set of static structure factors on the hexaaquairon(II) ion. The refinements are compared with the multipole treatment for atomic asphericity due to chemical bonding. In a treatment of the experimental data in which only the iron atom asphericity is considered, the 'thermal motion' formalism is as efficient as the multipole formalism in accounting for the observations. It is slightly less efficient when applied to the static theoretical data, though model maps based on the two treatments are remarkably similar. A high-order Gram-Charlier refinement of the porphyrin data, followed by a multipole refinement of all data with the Gram-Charlier parameters initially fixed, and later varied, shows that simultaneous refinement of anharmonic and aspherical effects is possible, though the resulting separation may not be accurate. A combined Gram-Charlier multipole refinement on the static data, however, leads to non-significant thermal parameters. It is concluded that the statistical Gram-Charlier formalism is remarkably successful in representing bonding effects in the valence charge density if these are not specifically accounted for in the scattering formalism. Statistical anharmonic thermal motion formalisms should only be used for X-ray data analysis in combination with a formalism accounting for the effect of bonding on the atomic charge density.
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Low-temperature study of bis(2-methylimidazole)(octaethylporphinato)iron(III) perchlorate. ACTA CRYSTALLOGRAPHICA SECTION B: STRUCTURAL SCIENCE 1987. [DOI: 10.1107/s0108768187097490] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Electron density studies of porphyrins and phthalocyanines. IV. Electron density distribution in crystals of (meso‐tetraphenylporphinato) iron(II). J Chem Phys 1986. [DOI: 10.1063/1.450617] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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