1
|
Dai L, Guo Z, Wang Z, Xu S, Wang S, Li W, Zhang G, Cheng YJ, Xia Y. Defensive and Ion Conductive Surface Layer Enables High Rate and Durable O3-type NaNi 1/3 Fe 1/3 Mn 1/3 O 2 Sodium-Ion Battery Cathode. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2305019. [PMID: 37661575 DOI: 10.1002/smll.202305019] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/13/2023] [Indexed: 09/05/2023]
Abstract
Na-based layered transition metal oxides with an O3-type structure are considered promising cathodes for sodium-ion batteries. However, rapid capacity fading, and poor rate performance caused by serious structural changes and interfacial degradation hamper their use. In this study, a NaPO3 surface modified O3-type layered NaNi1/3 Fe1/3 Mn1/3 O2 cathode is synthesized, with improved high-voltage stability through protecting layer against acid attack, which is achieved by a solid-gas reaction between the cathode particles and gaseous P2 O5 . The NaPO3 nanolayer on the surface effectively stabilizes the crystal structure by inhibiting surface parasitic reactions and increasing the observed average voltage. Superior cyclic stability is exhibited by the surface-modified cathode (80.1% vs 63.6%) after 150 cycles at 1 C in the wide voltage range of 2.0 V-4.2 V (vs Na+ /Na). Moreover, benefiting from the inherent ionic conduction of NaPO3 , the surface-modified cathode presents excellent rate capability (103 mAh g-1 vs 60 mAh g-1 ) at 10 C. The outcome of this study demonstrates a practically relevant approach to develop high rate and durable sodium-ion battery technology.
Collapse
Affiliation(s)
- Liling Dai
- School of Materials Science and Chemical Engineering, Ningbo University, Ningbo, 315211, P. R. China
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315211, P. R. China
| | - Ziyin Guo
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315211, P. R. China
| | - Zhao Wang
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315211, P. R. China
| | - Shunjie Xu
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315211, P. R. China
| | - Shuilong Wang
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315211, P. R. China
| | - Wenlu Li
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315211, P. R. China
| | - Guodong Zhang
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315211, P. R. China
| | - Ya-Jun Cheng
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315211, P. R. China
| | - Yonggao Xia
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315211, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| |
Collapse
|
2
|
Çamiçi HC, Guérineau T, Rivera VAG, Falci RF, LaRochelle S, Messaddeq Y. The role of tungsten oxide in Er 3+-doped bismuth-germanate glasses for optical amplification in L-band. Sci Rep 2023; 13:8835. [PMID: 37258637 DOI: 10.1038/s41598-023-35995-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 05/27/2023] [Indexed: 06/02/2023] Open
Abstract
A series of novel Er3+-doped bismuth-germanate glasses containing different tungsten concentrations with a molar composition of 97.5[(75 - x)GeO2-25Bi2O3-(x)WO3]-2Sb2O3-0.5Er2O3 (x = 5, 10, 15, 20, and 25 mol%) were fabricated. Their thermal properties are measured by differential scanning calorimetry. A structural investigation by Raman spectroscopy suggested that changes occurred in the glass network by WO3 incorporation. By laser excitation at 980 nm, a strong emission from Er3+ ions at 1532 nm is observed, while the WO3 addition caused changes in the emission spectra. The emission cross-section spectra of Er3+ are calculated by both McCumber and Füchtbauer-Ladenburg theories and their comparison showed these theories yielded slightly different results, but in both cases, the calculations showed that a gain signal in L-band can be achieved when 30% of the Er3+ ions are at the excited state. This study proves that the Er3+-doped bismuth-germanate glasses are suitable for optical fiber amplifier applications operating at C- and L-band.
Collapse
Affiliation(s)
- Hüseyin Can Çamiçi
- Centre for Optics, Photonics and Laser (COPL), Université Laval, 2375 rue de la Terrasse, Quebec, QC, Canada.
| | - Théo Guérineau
- Centre for Optics, Photonics and Laser (COPL), Université Laval, 2375 rue de la Terrasse, Quebec, QC, Canada
| | - V A G Rivera
- Centre for Optics, Photonics and Laser (COPL), Université Laval, 2375 rue de la Terrasse, Quebec, QC, Canada
| | - Rodrigo Ferreira Falci
- Centre for Optics, Photonics and Laser (COPL), Université Laval, 2375 rue de la Terrasse, Quebec, QC, Canada
| | - Sophie LaRochelle
- Centre for Optics, Photonics and Laser (COPL), Université Laval, 2375 rue de la Terrasse, Quebec, QC, Canada
| | - Younès Messaddeq
- Centre for Optics, Photonics and Laser (COPL), Université Laval, 2375 rue de la Terrasse, Quebec, QC, Canada
| |
Collapse
|
3
|
Yamazaki S, Shimizu D, Tani S, Honda K, Sumimoto M, Komaguchi K. Effect of Dispersants on Photochromic Behavior of Tungsten Oxide Nanoparticles in Methylcellulose. ACS APPLIED MATERIALS & INTERFACES 2018; 10:19889-19896. [PMID: 29767503 DOI: 10.1021/acsami.8b04875] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Tungsten oxide-based photochromic films that change reversibly in air between colorless-transparent in the dark and dark blue under UV irradiation were prepared by using methylcellulose as a film matrix and various dispersants. Alpha-hydroxyl acid such as glycolic acid (GA) or glyceric acid (GlyA) is the best dispersant because it can make the film transparent by adding a small quantity much less than that of 3-hydroxypropionic acid or ethylene glycol. Fourier-transform infrared spectra and Raman spectra indicate that a strong interaction exists between WO3 and GA or GlyA. The coloration and bleaching processes of the prepared films were investigated to clarify the effect of the dispersants and the moisture contents. The bleaching rate remarkably decreased in the films containing GA or GlyA but accelerated by increasing the contact with O2. Measurements of electron-spin resonance reveals that GA and GlyA as dispersants stabilize the W5+ state. This paper shows that the coloring rate and the period for keeping the blue-colored state are tunable by changing the dispersants. The photochromic films containing α-hydroxyl acid as the dispersant have the potential for application as rewritable film on which information displayed with blue-colored state can be clearly readable for longer times compared with other dispersants.
Collapse
Affiliation(s)
- Suzuko Yamazaki
- Division of Earth Science, Biology, and Chemistry, Graduate School of Sciences and Technology for Innovation , Yamaguchi University , Yoshida, Yamaguchi 753-8512 , Japan
| | - Dai Shimizu
- Division of Earth Science, Biology, and Chemistry, Graduate School of Sciences and Technology for Innovation , Yamaguchi University , Yoshida, Yamaguchi 753-8512 , Japan
| | - Seiji Tani
- Division of Earth Science, Biology, and Chemistry, Graduate School of Sciences and Technology for Innovation , Yamaguchi University , Yoshida, Yamaguchi 753-8512 , Japan
| | - Kensuke Honda
- Division of Earth Science, Biology, and Chemistry, Graduate School of Sciences and Technology for Innovation , Yamaguchi University , Yoshida, Yamaguchi 753-8512 , Japan
| | - Michinori Sumimoto
- Division of Applied Chemistry, Graduate School of Sciences and Technology for Innovation , Yamaguchi University , Tokiwadai, Ube 755-8611 , Japan
| | - Kenji Komaguchi
- Department of Applied Chemistry, Graduate School of Engineering , Hiroshima University , 1-4-1 Kagamiyama , Higashi-Hiroshima , Hiroshima 739-8527 , Japan
| |
Collapse
|
4
|
|
5
|
Ishiyama T, Yamaguchi T, Nishii J, Yamashita T, Kawazoe H, Kuwata N, Kawamura J, Omata T. Structural change of NaO1/2–WO3–NbO5/2–LaO3/2–PO5/2 glass induced by electrochemical substitution of sodium ions with protons. Phys Chem Chem Phys 2015; 17:13640-6. [DOI: 10.1039/c4cp05999a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fragments of phosphate chains in 1W-glass are induced by electrochemical substitution of Na+ ions with H+ (APS), despite the total number of modifier cations being unaffected by APS.
Collapse
Affiliation(s)
- Tomohiro Ishiyama
- Division of Materials and Manufacturing Science
- Graduate School of Engineering
- Osaka University
- Suita 565–0871
- Japan
| | - Takuya Yamaguchi
- Division of Materials and Manufacturing Science
- Graduate School of Engineering
- Osaka University
- Suita 565–0871
- Japan
| | - Junji Nishii
- Research Institute for Electronic Science
- Hokkaido University
- Sapporo 001-0021
- Japan
| | | | | | - Naoaki Kuwata
- Institute of Multidisciplinary Research for Advanced Materials
- IMRAM Tohoku University
- Sendai 980-8577
- Japan
| | - Junichi Kawamura
- Institute of Multidisciplinary Research for Advanced Materials
- IMRAM Tohoku University
- Sendai 980-8577
- Japan
| | - Takahisa Omata
- Division of Materials and Manufacturing Science
- Graduate School of Engineering
- Osaka University
- Suita 565–0871
- Japan
| |
Collapse
|
6
|
Rioux M, Ledemi Y, Viens J, Morency S, Ghaffari SA, Messaddeq Y. Optically-transparent and electrically-conductive AgI–AgPO3–WO3 glass fibers. RSC Adv 2015. [DOI: 10.1039/c5ra00681c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We report the fabrication, characterization, and fiber drawing of a silver iodide tungsten-phosphate glass that conducts both light and electricity efficiently.
Collapse
Affiliation(s)
- Maxime Rioux
- Department of Chemistry
- Laval University
- Quebec
- Canada
- Centre d'Optique
| | - Yannick Ledemi
- Centre d'Optique
- Photonique et Laser
- Université Laval
- Québec (Qc)
- Canada
| | - Jeff Viens
- Centre d'Optique
- Photonique et Laser
- Université Laval
- Québec (Qc)
- Canada
| | - Steeve Morency
- Centre d'Optique
- Photonique et Laser
- Université Laval
- Québec (Qc)
- Canada
| | | | - Younès Messaddeq
- Centre d'Optique
- Photonique et Laser
- Université Laval
- Québec (Qc)
- Canada
| |
Collapse
|
7
|
Taki Y, Shinozaki K, Honma T, Dimitrov V, Komatsu T. Electronic polarizability and interaction parameter of gadolinium tungsten borate glasses with high WO 3 content. J SOLID STATE CHEM 2014. [DOI: 10.1016/j.jssc.2014.08.035] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
8
|
|
9
|
Manzani D, de Araújo CB, Boudebs G, Messaddeq Y, Ribeiro SJL. The Role of Bi2O3 on the Thermal, Structural, and Optical Properties of Tungsten-Phosphate Glasses. J Phys Chem B 2012; 117:408-14. [DOI: 10.1021/jp3097296] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Danilo Manzani
- Instituto of Chemistry, São Paulo State University, UNESP, CP 355, Araraquara,
SP, 14801-970, Brazil
| | - Cid B. de Araújo
- Departamento
de Física, Universidade Federal de Pernambuco, 50670-901 Recife,
PE, Brazil
| | - Georges Boudebs
- LUNAM Université,
LPhiA,
Laboratoire de Photoniques d’Angers, EA 4464, Université d’Angers, 2 Boulevard Lavoisier,
49045 Angers Cedex 01, France
| | - Younès Messaddeq
- Instituto of Chemistry, São Paulo State University, UNESP, CP 355, Araraquara,
SP, 14801-970, Brazil
- Centre d’Optique, Photonique
et Laser, Université Laval, 2375
Rue de la Terrasse, G1 V 0A6 Québec, Canada
| | - Sidney J. L. Ribeiro
- Instituto of Chemistry, São Paulo State University, UNESP, CP 355, Araraquara,
SP, 14801-970, Brazil
| |
Collapse
|
10
|
Larink D, Ren J, Eckert H. Spectral editing based on scalar spin-spin interactions: new results on the structure of metathiophosphate glasses. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2012; 45-46:30-35. [PMID: 22664187 DOI: 10.1016/j.ssnmr.2012.05.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 05/09/2012] [Indexed: 06/01/2023]
Abstract
The local structure of glassy NaPS(3) and AgPS(3) was analyzed based on quantitative (31)P MAS-NMR spectroscopy. The glasses contain some oxide impurities, which could be quantified from the NMR spectral analysis. Four discrete resonances are observed in both glasses, which were assigned to four distinct types of phosphate groups P((n)), where n is the number of P-S-P bridges(i.e., P((0)), P((1)), P((2)), and P((3)) units, respectively) with the help of 2D homonuclear J-resolved and INADEQUATE methods. Based on the results obtained, the interpretations of previous spectra obtained at low spinning speeds on lithium and silver thiophosphate glasses (Chem. Mater. 2 (1990), 273, and J. Am. Chem. Soc. 114 (1992), 5775) need to be revised. Contrary to the situation in alkali phosphate glasses, the corresponding sulfide analogs are characterized by a wide P((n)) species distribution close to that predicted by a statistical charge distribution. INADEQUATE experiments fail to detect P((n))-P((n-1)) connectivities, suggesting that the structure of these glasses is rather inhomogeneous, possibly featuring the different P((n)) species in segregated domains.
Collapse
Affiliation(s)
- Dirk Larink
- Institut für Physikalische Chemie, WWU Münster, Münster, Germany
| | | | | |
Collapse
|
11
|
Barbosa AJ, Maia LJQ, Montanari B, Gonçalves RR, Messaddeq Y, Ferreira RAS, Carlos LD, Ribeiro SJL. Enhanced Eu3+ emission in aqueous phosphotungstate colloidal systems: stabilization of polyoxometalate nanostructures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:14170-14176. [PMID: 20684653 DOI: 10.1021/la100525h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Luminescent Eu(3+)-containing polyphosphate-tungstate aqueous colloidal systems were prepared and studied as a function of the relative polyphosphate-tungstate content. In polyphosphate-rich solutions, Eu(3+) ions occupy cagelike sites composed of phosphate groups from the metaphosphate chains. In these sites, an average number of 0.5 water molecule coordinates to an Eu(3+) ion and the (5)D(0) emission quantum efficiency is 0.22. Tungstate addition leads to important modifications in neighboring Eu(3+) leading to coordination sites in the aqueous medium where metal ions are completely hidden from interactions with solvent molecules. Transmission electron microscopy results clearly show W-rich nanoparticles with sizes between 5 and 10 nm for all tungstate relative concentrations. For high tungstate relative contents (above 30 mol %), spectroscopic results suggest the presence of Eu(3+) in polyoxometalate (POM)-like sites by comparison with the well-known decatungstoeuropate [EuW(10)O(36)](9-) structure. These new aqueous colloids display surprisingly high (5)D(0) emission quantum efficiencies of ca 80% because of the strong ligand field provided by tungstate POM ligands and the complete absence of water molecules from the Eu(3+) first coordination shell.
Collapse
Affiliation(s)
- A J Barbosa
- Institute of Chemistry, São Paulo State University-UNESP, CP 355, Araraquara-SP 14801-970, Brazil
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Zhang Z, Qu Y, Wang S, Wang J. Catalytic Performance and Characterization of Silica Supported Sodium Phosphates for the Dehydration of Methyl Lactate to Methyl Acrylate andAcrylic Acid. Ind Eng Chem Res 2009. [DOI: 10.1021/ie900065a] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zhiqiang Zhang
- Beijing Key Laboratory of Bioprocess, College of Chemical Engineering, Beijing University of Chemical Technology, Beisuanhuan East Road 15, Chaoyang District, Beijing 10029, China
| | - Yixin Qu
- Beijing Key Laboratory of Bioprocess, College of Chemical Engineering, Beijing University of Chemical Technology, Beisuanhuan East Road 15, Chaoyang District, Beijing 10029, China
| | - Shui Wang
- Beijing Key Laboratory of Bioprocess, College of Chemical Engineering, Beijing University of Chemical Technology, Beisuanhuan East Road 15, Chaoyang District, Beijing 10029, China
| | - Jidong Wang
- Beijing Key Laboratory of Bioprocess, College of Chemical Engineering, Beijing University of Chemical Technology, Beisuanhuan East Road 15, Chaoyang District, Beijing 10029, China
| |
Collapse
|
13
|
Guerry P, Smith ME, Brown SP. 31P MAS Refocused INADEQUATE Spin−Echo (REINE) NMR Spectroscopy: Revealing J Coupling and Chemical Shift Two-Dimensional Correlations in Disordered Solids. J Am Chem Soc 2009; 131:11861-74. [DOI: 10.1021/ja902238s] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Paul Guerry
- Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
| | - Mark E. Smith
- Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
| | - Steven P. Brown
- Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
| |
Collapse
|
14
|
Brown SP. Recent Advances in Solid-State MAS NMR Methodology for Probing Structure and Dynamics in Polymeric and Supramolecular Systems. Macromol Rapid Commun 2009; 30:688-716. [DOI: 10.1002/marc.200800816] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 02/06/2009] [Indexed: 01/12/2023]
|
15
|
Joyce SA, Yates JR, Pickard CJ, Brown SP. Density Functional Theory Calculations of Hydrogen-Bond-Mediated NMR J Coupling in the Solid State. J Am Chem Soc 2008; 130:12663-70. [DOI: 10.1021/ja800419m] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Siân A. Joyce
- Tyndall National Institute, Lee Maltings, Prospect Row, Cork, Ireland, TCM Group, Cavendish Laboratory, University of Cambridge, 19 J. J. Thomson Avenue, Cambridge CB3 OHE, U.K., School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, U.K., and Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
| | - Jonathan R. Yates
- Tyndall National Institute, Lee Maltings, Prospect Row, Cork, Ireland, TCM Group, Cavendish Laboratory, University of Cambridge, 19 J. J. Thomson Avenue, Cambridge CB3 OHE, U.K., School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, U.K., and Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
| | - Chris J. Pickard
- Tyndall National Institute, Lee Maltings, Prospect Row, Cork, Ireland, TCM Group, Cavendish Laboratory, University of Cambridge, 19 J. J. Thomson Avenue, Cambridge CB3 OHE, U.K., School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, U.K., and Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
| | - Steven P. Brown
- Tyndall National Institute, Lee Maltings, Prospect Row, Cork, Ireland, TCM Group, Cavendish Laboratory, University of Cambridge, 19 J. J. Thomson Avenue, Cambridge CB3 OHE, U.K., School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, U.K., and Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
| |
Collapse
|
16
|
Griffin JM, Tripon C, Samoson A, Filip C, Brown SP. Low-load rotor-synchronised Hahn-echo pulse train (RS-HEPT) 1H decoupling in solid-state NMR: factors affecting MAS spin-echo dephasing times. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2007; 45 Suppl 1:S198-S208. [PMID: 18098353 DOI: 10.1002/mrc.2145] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Transverse dephasing times T(2)' in spin-echo MAS NMR using rotor-synchronised Hahn-echo pulse-train (RS-HEPT) low-load (1)H decoupling are evaluated. Experiments were performed at 300 and 600 MHz for (13)CH-labelled L-alanine and (15)NH(delta)-labelled L-histidine.HCl.H(2)O, together with SPINEVOLUTION simulations for a ten-spin system representing the crystal structure environment of the (13)CH carbon in L-alanine. For 30 kHz MAS and nu(1)((1)H) = 100 kHz at 300 MHz, a RS-HEPT T(2)' value of 17 +/- 1 ms was obtained for (13)CH-labelled L-alanine which is approximately 50% of the XiX T(2)' value of 33 +/- 2 ms. Optimum RS-HEPT decoupling performance is observed for a relative phase of alternate RS-HEPT pi-pulses, Deltaphi = phi'- phi, between 40 and 60 degrees . For experiments at 600 MHz and 30 kHz MAS with (13)CH-labelled L-alanine, the best RS-HEPT (nu(1)((1)H) = 100 kHz) T(2)' value was 3 times longer than that observed for low-power continuously applied sequences with nu(1)((1)H) < or =40 kHz, i.e. corresponding to the same average power dissipated in the probe. A marked improvement in RS-HEPT (1)H decoupling is observed for increasing MAS frequency: at 55.6 kHz MAS, a best RS-HEPT T(2)' value of 34 +/- 5 ms was recorded for (13)CH-labelled L-alanine. Much improved RS-HEPT broadband performance was also observed at 55.6 kHz MAS as compared to 30 kHz MAS.
Collapse
Affiliation(s)
- John M Griffin
- Department of Physics, University of Warwick, Coventry, UK
| | | | | | | | | |
Collapse
|
17
|
Rinke MT, Zhang L, Eckert H. Structural integration of tellurium oxide into mixed-network-former glasses: connectivity distribution in the system NaPO(3)-TeO(2). Chemphyschem 2007; 8:1988-98. [PMID: 17726674 DOI: 10.1002/cphc.200700358] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Sodium phosphate tellurite glasses in the system (NaPO(3))(x)(TeO(2))(1-) (x) were prepared and structurally characterized by thermal analysis, vibrational spectroscopy, X-ray photoelectron spectroscopy (XPS) and a variety of complementary solid-state nuclear magnetic resonance (NMR) techniques. Unlike the situation in other mixed-network-former glasses, the interaction between the two network formers tellurium oxide and phosphorus oxide produces no new structural units, and no sharing of the network modifier Na(2)O takes place. The glass structure can be regarded as a network of interlinked metaphosphate-type P(2) tetrahedral and TeO(4/2) antiprismatic units. The combined interpretation of the O 1s XPS data and the (31)P solid-state NMR spectra presents clear quantitative evidence for a nonstatistical connectivity distribution. Rather, the formation of homoatomic P--O--P and Te--O--Te linkages is favored over mixed P--O--Te connectivities. As a consequence of this chemical segregation effect, the spatial sodium distribution is not random, as also indicated by a detailed analysis of (31)P/(23)Na rotational echo double-resonance (REDOR) experiments.
Collapse
Affiliation(s)
- Matthias T Rinke
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 30, 48149, Münster, Germany
| | | | | |
Collapse
|
18
|
Santagneli SH, de Araujo CC, Strojek W, Eckert H, Poirier G, Ribeiro SJL, Messaddeq Y. Structural Studies of NaPO3−MoO3 Glasses by Solid-State Nuclear Magnetic Resonance and Raman Spectroscopy. J Phys Chem B 2007; 111:10109-17. [PMID: 17683136 DOI: 10.1021/jp072883n] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Vitreous samples were prepared in the (100 - x)% NaPO(3)-x% MoO(3) (0 <or= x <or= 70) glass-forming system by a modified melt method that allowed good optical quality samples to be obtained. The structural evolution of the vitreous network was monitored as a function of composition by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), Raman scattering, and solid-state nuclear magnetic resonance (NMR) for (31)P, (23)Na, and (95)Mo nuclei. Addition of MoO(3) to the NaPO(3) glass melt leads to a pronounced increase in the glass transition temperatures up to x = 45, suggesting a significant increase in network connectivity. For this same composition range, vibrational spectra suggest that the Mo(6+) ions are bonded to some nonbridging oxygen atoms (Mo-O- or Mo=O bonded species). Mo-O-Mo bond formation occurs only at MoO(3) contents exceeding x = 45. (31)P magic-angle spinning (MAS) NMR spectra, supported by two-dimensional J-resolved spectroscopy, allow a clear distinction between species having two, one, and zero P-O-P linkages. These sites are denoted as Q(2)(2Mo), Q(2)(1Mo), and Q(2)(0Mo), respectively. For x < 0.45, the populations of these sites can be described along the lines of a binary model, according to which each unit of MoO(3) converts two Q(2)(nMo) sites into two Q(2)((n+1)Mo) sites (n = 0, 1). This structural model is consistent with the presence of tetrahedral Mo(=O)2(O(1/2))2 environments. Indeed, (95)Mo NMR data suggest that the majority of the molybdenum species are four-coordinated. However, the presence of additional six-coordinate molybdenum in the MAS NMR spectra indicates that the structure of these glasses may be more complicated and may additionally involve sharing of network modifier oxide between the network formers phosphorus and molybdenum. This latter hypothesis is further supported by (23)Na{(31)P} rotational echo double resonance (REDOR) data, which clearly reveal that the magnetic dipole-dipole interactions between (31)P and (23)Na are increasingly diminished with increasing molybdenum content. The partial transfer of modifier from the phosphate to the molybdate network former implies a partial repolymerization of the phosphate species, resulting in the formation of Q(3)(nMo) species and accounting for the observed increase in the glass transition temperature with increasing MoO(3) content that is observed in the composition range 0 <or= x <or= 45. Glasses with MoO(3) contents beyond x = 45 show decreased thermal and crystallization stability. Their structure is characterized by isolated phosphate species [most likely of the P(OMo)4 type] and molybdenum oxide clusters with a large extent of Mo-O-Mo connectivity.
Collapse
Affiliation(s)
- Silvia H Santagneli
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 30, D-48149 Münster, Germany
| | | | | | | | | | | | | |
Collapse
|
19
|
Pham TN, Griffin JM, Masiero S, Lena S, Gottarelli G, Hodgkinson P, Filip C, Brown SP. Quantifying hydrogen-bonding strength: the measurement of 2hJNN couplings in self-assembled guanosines by solid-state 15N spin-echo MAS NMR. Phys Chem Chem Phys 2007; 9:3416-23. [PMID: 17664965 DOI: 10.1039/b703513f] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
(2h)J(NN) hydrogen-bond mediated J couplings are measured in the solid state for two synthetic deoxyguanosine derivatives by (15)N MAS NMR spin-echo experiments. The use of rotor-synchronised Hahn-echo pulse train (RS-HEPT) (1)H decoupling, with a duty cycle of 6%, allows spin-echo durations out to 200 ms, hence enabling the accurate determination of J couplings as small as 3.8 Hz. A single-crystal X-ray diffraction structure exists for the shorter alkyl chain derivative dG(C(3))(2): the observation of significantly different (2h)J(NN) couplings, 6.2 +/- 0.4 and 7.4 +/- 0.4 Hz, for the two resolved N7 resonances is to be expected given the NH...N hydrogen-bonding distances of 2.91 and 2.83 A for the two distinct molecules in the asymmetric unit cell. For the longer alkyl chain derivative, dG(C(10))(2), for which there is no single-crystal diffraction structure, a (15)N refocused INADEQUATE spectrum (Pham et al., J. Am. Chem. Soc., 2005, 127, 16018-16019) has demonstrated the presence of N2-H...N7 intermolecular hydrogen-bonds indicative of a quartet-like structure. The (2h)J(NN) hydrogen-bond mediated J coupling of 5.9 +/- 0.2 Hz is at the lower end of the range (5.9-8.2 Hz) of (2h)J(NN) couplings determined from solution-state NMR of guanosine quartets in quadruplex DNA. A full discussion of the determination of error bars on the fitted parameters is given; specifically, error bars determined by a non-linear fitting (using the covariance matrix) or in a Monte-Carlo fashion are found to give effectively identical results.
Collapse
Affiliation(s)
- Tran N Pham
- Department of Physics, University of Warwick, Coventry, UK CV4 7AL
| | | | | | | | | | | | | | | |
Collapse
|