1
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Perras FA, Thomas H, Heintz P, Behera R, Yu J, Viswanathan G, Jing D, Southern SA, Kovnir K, Stanley L, Huang W. The Structure of Boron Monoxide. J Am Chem Soc 2023; 145:14660-14669. [PMID: 37378579 DOI: 10.1021/jacs.3c02070] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
Boron monoxide (BO), prepared by the thermal condensation of tetrahydroxydiboron, was first reported in 1955; however, its structure could not be determined. With the recent attention on boron-based two-dimensional materials, such as borophene and hexagonal boron nitride, there is renewed interest in BO. A large number of stable BO structures have been computationally identified, but none are supported by experiments. The consensus is that the material likely forms a boroxine-based two-dimensional material. Herein, we apply advanced 11B NMR experiments to determine the relative orientations of B(B)O2 centers in BO. We find that the material is composed of D2h-symmetric O2B-BO2 units that organize to form larger B4O2 rings. Further, powder diffraction experiments additionally reveal that these units organize to form two-dimensional layers with a random stacking pattern. This observation is in agreement with earlier density functional theory (DFT) studies that showed B4O2-based structures to be the most stable.
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Affiliation(s)
- Frédéric A Perras
- Chemical and Biological Sciences Division, Ames National Laboratory, Ames, Iowa 50011, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Henry Thomas
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Patrick Heintz
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Ranjan Behera
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Jiaqi Yu
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Gayatri Viswanathan
- Chemical and Biological Sciences Division, Ames National Laboratory, Ames, Iowa 50011, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Dapeng Jing
- Materials Analysis and Research Laboratory, Iowa State University, Ames, Iowa 50011, United States
| | - Scott A Southern
- Chemical and Biological Sciences Division, Ames National Laboratory, Ames, Iowa 50011, United States
| | - Kirill Kovnir
- Chemical and Biological Sciences Division, Ames National Laboratory, Ames, Iowa 50011, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Levi Stanley
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Wenyu Huang
- Chemical and Biological Sciences Division, Ames National Laboratory, Ames, Iowa 50011, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
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2
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Agarwal S, Kattnig DR, Aiello CD, Banerjee AS. The Biological Qubit: Calcium Phosphate Dimers, Not Trimers. J Phys Chem Lett 2023; 14:2518-2525. [PMID: 36876913 DOI: 10.1021/acs.jpclett.2c03945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The Posner molecule (calcium phosphate trimer, Ca9(PO4)6) has been hypothesized to function as a biological quantum information processor due to its supposedly long-lived entangled 31P nuclear spin states. This hypothesis was challenged by our recent finding that the molecule lacks a well-defined rotational axis of symmetry─an essential assumption in the proposal for Posner-mediated neural processing─and exists as an asymmetric dynamical ensemble. Following up, we investigate here the spin dynamics of the molecule's entangled 31P nuclear spins within the asymmetric ensemble. Our simulations show that entanglement between two nuclear spins prepared in a Bell state in separate Posner molecules decays on a subsecond time scale─much faster than previously hypothesized, and not long enough for supercellular neuronal processing. Calcium phosphate dimers (Ca6(PO4)4) however, are found to be surprisingly resilient to decoherence and are able to preserve entangled nuclear spins for hundreds of seconds, suggesting that neural processing might occur through them instead.
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Affiliation(s)
- Shivang Agarwal
- Department of Electrical and Computer Engineering, University of California, Los Angeles, California 90095, United States
| | - Daniel R Kattnig
- Department of Physics and Living Systems Institute, University of Exeter, EX4 4QL, Exeter, U.K
| | - Clarice D Aiello
- Department of Electrical and Computer Engineering, University of California, Los Angeles, California 90095, United States
| | - Amartya S Banerjee
- Department of Materials Science and Engineering, University of California, Los Angeles, California 90095, United States
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3
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Agarwal S, Aiello CD, Kattnig DR, Banerjee AS. The Dynamical Ensemble of the Posner Molecule Is Not Symmetric. J Phys Chem Lett 2021; 12:10372-10379. [PMID: 34668712 DOI: 10.1021/acs.jpclett.1c02796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The Posner molecule, Ca9(PO4)6, has long been recognized to have biochemical relevance in various physiological processes. It has found recent attention for its possible role as a biological quantum information processor, whereby the molecule purportedly maintains long-lived nuclear spin coherences among its 31P nuclei (presumed to be symmetrically arranged), allowing it to function as a room temperature qubit. The structure of the molecule has been of much dispute in the literature, although the S6 point group symmetry has often been assumed and exploited in calculations. Using a variety of simulation techniques (including ab initio molecular dynamics and structural relaxation), rigorous data analysis tools, and by exploring thousands of individual configurations, we establish that the molecule predominantly assumes low-symmetry structures (Cs and Ci) at room temperature, as opposed to the higher-symmetry configurations explored previously. Our findings have important implications for the viability of this molecule as a qubit.
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Affiliation(s)
- Shivang Agarwal
- Department of Electrical and Computer Engineering, University of California, Los Angeles 90095, United States
| | - Clarice D Aiello
- Department of Electrical and Computer Engineering, University of California, Los Angeles 90095, United States
| | - Daniel R Kattnig
- Department of Physics and Living Systems Institute, University of Exeter, Exeter EX4 4QD, U.K
| | - Amartya S Banerjee
- Department of Materials Science and Engineering, University of California, Los Angeles 90095, United States
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4
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Pourpoint F, Venel F, Giovine R, Trébosc J, Vancompernolle T, Taoufik M, Sarou-Kanian V, Gauvin RM, Lafon O. Probing 29Si- 17O connectivities and proximities by solid-state NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 330:107029. [PMID: 34311423 DOI: 10.1016/j.jmr.2021.107029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 06/18/2021] [Accepted: 06/22/2021] [Indexed: 06/13/2023]
Abstract
The measurement of dipolar and J- couplings between 29Si and 17O isotopes is challenging owing to (i) the low abundance of both isotopes and (ii) their close Larmor frequencies, which only differ by 19%. These issues are circumvented here by the use of isotopic enrichment and dedicated triple-resonance magic-angle spinning NMR probe. The surface of 29Si-enriched silica was labelled with 17O isotope and heated at 80 and 200 °C. 29Si-17O connectivities and proximities were probed using two-dimensional (2D) through-bond and through-space heteronuclear multiple-quantum coherences (J- and D-HMQC) experiments between 17O and 29Si nuclei. The simulation of the build-up of the J- and D-HMQC signals allowed the first experimental measurement of J- and dipolar coupling constants between 17O and 29Si nuclei. These HMQC experiments allow distinguishing two distinct siloxane (SiOSi) oxygen sites: (i) those covalently bonded to Q3 and Q4 groups, having a hydroxyl group as a second neighbour and (ii) those covalently bonded to two Q4 groups. The measured J- and dipolar coupling constants of siloxane 17O nucleus with Q4 29Si nuclei differ from those with Q3 29Si nuclei. These results indicate that the 29Si-17O one-bond J-coupling and Si-O bond length depend on the second neighbours of the Si atoms.
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Affiliation(s)
- Frédérique Pourpoint
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181-UCCS- Unité de Catalyse et Chimie du Solide, F-59000 Lille, France.
| | - Florian Venel
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181-UCCS- Unité de Catalyse et Chimie du Solide, F-59000 Lille, France
| | - Raynald Giovine
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181-UCCS- Unité de Catalyse et Chimie du Solide, F-59000 Lille, France
| | - Julien Trébosc
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181-UCCS- Unité de Catalyse et Chimie du Solide, F-59000 Lille, France
| | - Tom Vancompernolle
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181-UCCS- Unité de Catalyse et Chimie du Solide, F-59000 Lille, France
| | - Mostafa Taoufik
- Université Lyon 1, Institut de Chimie de Lyon, CPE Lyon, CNRS, UMR 5265 C2P2, LCOMS, Bâtiment 308 F 43 Blvd du 11 Novembre 1918 F-69616, Villeurbanne Cedex, France
| | - Vincent Sarou-Kanian
- CEMHTI, CNRS, UPR 3079, 1D avenue de la Recherche Scientifique, 45071 Orléans Cedex 2, France
| | - Régis M Gauvin
- PSL Research University, Chimie ParisTech - CNRS, Institut de Recherche de Chimie Paris, 75005 Paris, France
| | - Olivier Lafon
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181-UCCS- Unité de Catalyse et Chimie du Solide, F-59000 Lille, France; Institut Universitaire de France, France
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Ewing WC, Dellermann T, Angel Wong YT, Mattock JD, Vargas A, Bryce DL, Dewhurst RD, Braunschweig H. π-Complexes of Diborynes with Main Group Atoms. Chem Asian J 2020; 15:1553-1557. [PMID: 32207211 PMCID: PMC7317709 DOI: 10.1002/asia.202000185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/19/2020] [Indexed: 12/02/2022]
Abstract
We present herein an in-depth study of complexes in which a molecule containing a boron-boron triple bond is bound to tellurate cations. The analysis allows the description of these salts as true π complexes between the B-B triple bond and the tellurium center. These complexes thus extend the well-known Dewar-Chatt-Duncanson model of bonding to compounds made up solely of p block elements. Structural, spectroscopic and computational evidence is offered to argue that a set of recently reported heterocycles consisting of phenyltellurium cations complexed to diborynes bear all the hallmarks of π-complexes in the π-complex/metallacycle continuum envisioned by Joseph Chatt. Described as such, these compounds are unique in representing the extreme of a metal-free continuum with conventional unsaturated three-membered rings (cyclopropenes, azirenes, borirenes) occupying the opposite end.
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Affiliation(s)
- William C. Ewing
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Theresa Dellermann
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Y. T. Angel Wong
- Department of Chemistry and Biomolecular SciencesUniversity of OttawaOttawaOntarioK1N 6N5Canada
| | - James D. Mattock
- Department of ChemistrySchool of Life SciencesUniversity of SussexBrightonBN1 9QJSussexUK
| | - Alfredo Vargas
- Department of ChemistrySchool of Life SciencesUniversity of SussexBrightonBN1 9QJSussexUK
| | - David L. Bryce
- Department of Chemistry and Biomolecular SciencesUniversity of OttawaOttawaOntarioK1N 6N5Canada
| | - Rian D. Dewhurst
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Holger Braunschweig
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
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6
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Cid J, Hermann A, Radcliffe JE, Curless LD, Braunschweig H, Ingleson MJ. Synthesis of Unsymmetrical Diboron(5) Compounds and Their Conversion to Diboron(5) Cations. Organometallics 2018. [DOI: 10.1021/acs.organomet.8b00288] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jessica Cid
- School of Chemistry, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Alexander Hermann
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - James E. Radcliffe
- School of Chemistry, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Liam D. Curless
- School of Chemistry, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Holger Braunschweig
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Michael J. Ingleson
- School of Chemistry, The University of Manchester, Manchester M13 9PL, United Kingdom
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7
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Zhang C, Luo Q, Cheng S, Bu Y. Unusual Indirect Nuclear Spin-Spin Exchange Coupling through Solvated Electron. J Phys Chem Lett 2018; 9:689-695. [PMID: 29369635 DOI: 10.1021/acs.jpclett.7b03249] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Solvated electrons have been found to exist in various media which also exhibit more intriguing properties such as superconductivity, nonlinear optical response, and so on. However, how they affect the nuclear spin properties has not been proven. In this work, we present the first detailed study on solvated-electron-triggered indirect nuclear spin-spin J-coupling using density functional theory calculations. Taking 19F as a probe, we verify the presence of unusual J couplings between two distant F atoms in HF-containing anionic clusters. These couplings occur "through solvated electron", rather than through conventional covalent bonds or space. Solvated electron can serve as an additional channel to efficiently realize long-range J-coupling between far separated nuclei because of its dispersivity and Rydberg character. The coupling magnitude strongly depends on the unique distribution of solvated electron and its second-order interaction with solvating HF units. This work provides novel insights into the mediating roles of electrons, possibly opening up potential applications based on weakly bound electrons.
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Affiliation(s)
- Changzhe Zhang
- School of Chemistry and Chemical Engineering, Shandong University , Jinan, 250100, People's Republic of China
| | - Qi Luo
- School of Chemistry and Chemical Engineering, Shandong University , Jinan, 250100, People's Republic of China
| | - Shibo Cheng
- School of Chemistry and Chemical Engineering, Shandong University , Jinan, 250100, People's Republic of China
| | - Yuxiang Bu
- School of Chemistry and Chemical Engineering, Shandong University , Jinan, 250100, People's Republic of China
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8
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Bryce DL. NMR crystallography: structure and properties of materials from solid-state nuclear magnetic resonance observables. IUCRJ 2017; 4:350-359. [PMID: 28875022 PMCID: PMC5571798 DOI: 10.1107/s2052252517006042] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 04/21/2017] [Indexed: 05/20/2023]
Abstract
This topical review provides a brief overview of recent developments in NMR crystallography and related NMR approaches to studying the properties of molecular and ionic solids. Areas of complementarity with diffraction-based methods are underscored. These include the study of disordered systems, of dynamic systems, and other selected examples where NMR can provide unique insights. Highlights from the literature as well as recent work from my own group are discussed.
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Affiliation(s)
- David L. Bryce
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie Private, Ottawa, Ontario K1N 6N5, Canada
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9
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Kobera L, Southern SA, Frost JM, Bryce DL. Multinuclear solid-state magnetic resonance study of oxo-bridged diniobium and quadruply-bonded dimolybdenum carboxylate clusters. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2017; 84:20-27. [PMID: 27986401 DOI: 10.1016/j.ssnmr.2016.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 12/01/2016] [Accepted: 12/02/2016] [Indexed: 06/06/2023]
Abstract
Carboxylate paddlewheels and their oxo-bridged analogues constitute ideal building blocks for the assembly of two- and three-dimensional framework materials. Here, we present a multinuclear (1H, 13C, 93Nb, 95Mo) magnetic resonance study of solid samples of Nb2OCl6(O2Ph)2 (1), Mo2(O2CMe)4 (2), and Mo2(O2CCHF2)4 (3). High-resolution proton and 13C CP/MAS NMR spectra provide valuable information on structure and crystal symmetry and on cocrystallized solvent. 93Nb solid-state NMR spectra of 1 provide quadrupolar coupling constants and chemical shift tensors which are characteristic of the axially asymmetric Nb-O-Nb bridging environment. 95Mo solid-state NMR spectra of 2 and 3 provide quadrupolar coupling constants and chemical shift tensors which are directly characteristic of the molybdenum-molybdenum quadruple bonds in these compounds. The quadruple bonds are characterized by particularly large 95Mo chemical shift tensor spans on the order of 5500ppm. Density functional theoretical computations provide good agreement with the 93Nb and 95Mo experimental data, with some exceptions noted. This work demonstrates possible NMR approaches to characterize more complex framework materials and provides key insight into the Mo-Mo quadruple bond.
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Affiliation(s)
- Libor Kobera
- Department of Chemistry and Biomolecular Sciences&Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie Private, Ottawa, Ontario K1N6N5, Canada
| | - Scott A Southern
- Department of Chemistry and Biomolecular Sciences&Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie Private, Ottawa, Ontario K1N6N5, Canada
| | - Jamie M Frost
- Department of Chemistry and Biomolecular Sciences&Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie Private, Ottawa, Ontario K1N6N5, Canada
| | - David L Bryce
- Department of Chemistry and Biomolecular Sciences&Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie Private, Ottawa, Ontario K1N6N5, Canada.
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10
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Wong YTA, Landmann J, Finze M, Bryce DL. Dynamic Disorder and Electronic Structures of Electron-Precise Dianionic Diboranes: Insights from Solid-State Multinuclear Magnetic Resonance Spectroscopy. J Am Chem Soc 2017; 139:8200-8211. [PMID: 28548827 DOI: 10.1021/jacs.7b01783] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The J(11B,11B) coupling constants of various salts of the electron-precise hexacyanodiborane(6) dianion, [B2(CN)6]2-, were obtained using 11B double-quantum-filtered (DQF) J-resolved solid-state nuclear magnetic resonance (SSNMR) spectroscopy. Our results show that the magnitude of the DQF J splitting is influenced by both the crystallographic symmetry of the system and the presence of dynamics. The splittings are amplified by a factor of 3 as compared to the corresponding theoretical J coupling constants for cases where (1) there is an absence of dynamics but the boron pairs are crystallographically equivalent or (2) the boron pairs are crystallographically inequivalent but are rendered magnetically equivalent on the time scale of the experiment due to dynamic disorder, which was identified by 11B and 13C SSNMR experiments. Consequently, molecular motions need to be taken into consideration when interpreting the results of DQF J-resolved experiments, and conversely, these experiments may be used to identify dynamic disorder. Variable-temperature NMR data support the notion of three different motional processes with correlation times ranging from 102 to 106 s-1 over the temperature range of 248-306 K. When molecular motion and crystallographic symmetry are both accounted for, the J(11B,11B) coupling constants for various [B2(CN)6]2- salts were measured to range from 29.4 to 35.8 Hz, and their electronic origins were determined using natural localized molecular orbital and natural bond orbital analyses. The coupling constants were found to strongly correlate to the hybridization states of the boron orbitals that form the B-B bonds and to the strength of the B-B bonds. This study provides a novel tool to study dynamics in ordered and disordered solids and provides new perspectives on electron-precise dianionic diboranes featuring two-center-two-electron bonds in the context of related compounds featuring multiply and singly bonded boron spin pairs.
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Affiliation(s)
- Y T Angel Wong
- Department of Chemistry and Biomolecular Sciences & Centre for Catalysis Research and Innovation, University of Ottawa , Ottawa, Ontario, Canada K1N6N5
| | - Johannes Landmann
- Institut für Anorganische Chemie, Institut für nachhaltige Chemie & Katalyse mit Bor (ICB), Julius-Maximilians-Universität Würzburg , Am Hubland, 97074 Würzburg, Germany
| | - Maik Finze
- Institut für Anorganische Chemie, Institut für nachhaltige Chemie & Katalyse mit Bor (ICB), Julius-Maximilians-Universität Würzburg , Am Hubland, 97074 Würzburg, Germany
| | - David L Bryce
- Department of Chemistry and Biomolecular Sciences & Centre for Catalysis Research and Innovation, University of Ottawa , Ottawa, Ontario, Canada K1N6N5
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11
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Brus J, Czernek J, Urbanova M, Kobera L, Jegorov A. An efficient 2D 11B–11B solid-state NMR spectroscopy strategy for monitoring covalent self-assembly of boronic acid-derived compounds: the transformation and unique architecture of bortezomib molecules in the solid state. Phys Chem Chem Phys 2017; 19:487-495. [DOI: 10.1039/c6cp06555d] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An efficient 2D 11B–11B ssNMR strategy for exploring the covalent assembly of boronic acid derivatives in the solid state is demonstrated.
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Affiliation(s)
- J. Brus
- Institute of Macromolecular Chemistry
- Academy of Sciences of the Czech Republic
- 162 06 Prague 6
- Czech Republic
| | - J. Czernek
- Institute of Macromolecular Chemistry
- Academy of Sciences of the Czech Republic
- 162 06 Prague 6
- Czech Republic
| | - M. Urbanova
- Institute of Macromolecular Chemistry
- Academy of Sciences of the Czech Republic
- 162 06 Prague 6
- Czech Republic
| | - L. Kobera
- Institute of Macromolecular Chemistry
- Academy of Sciences of the Czech Republic
- 162 06 Prague 6
- Czech Republic
| | - A. Jegorov
- Teva Czech Industries s.r.o
- 370 05 Ceske Budejovice
- Czech Republic
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12
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Kobera L, Southern SA, Rao GK, Richeson DS, Bryce DL. New Experimental Insight into the Nature of Metal−Metal Bonds in Digallium Compounds:JCoupling between Quadrupolar Nuclei. Chemistry 2016; 22:9565-73. [DOI: 10.1002/chem.201600999] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Libor Kobera
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation; University of Ottawa; 10 Marie Curie Pvt. D'Iorio Hall Ottawa Ontario K1N 6N5 Canada
| | - Scott A. Southern
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation; University of Ottawa; 10 Marie Curie Pvt. D'Iorio Hall Ottawa Ontario K1N 6N5 Canada
| | - Gyandshwar Kumar Rao
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation; University of Ottawa; 10 Marie Curie Pvt. D'Iorio Hall Ottawa Ontario K1N 6N5 Canada
| | - Darrin S. Richeson
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation; University of Ottawa; 10 Marie Curie Pvt. D'Iorio Hall Ottawa Ontario K1N 6N5 Canada
| | - David L. Bryce
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation; University of Ottawa; 10 Marie Curie Pvt. D'Iorio Hall Ottawa Ontario K1N 6N5 Canada
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13
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Cuenca AB, Zigon N, Duplan V, Hoshino M, Fujita M, Fernández E. Undeniable Confirmation of the syn
-Addition Mechanism for Metal-Free Diboration by Using the Crystalline Sponge Method. Chemistry 2016; 22:4723-6. [DOI: 10.1002/chem.201600392] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Ana B. Cuenca
- Department Quimica Física i Inorgànica; University Rovira i Virgili; C/Marcel⋅lí Domingo s/n 43007 Tarragona Spain
| | - Nicolas Zigon
- Department of Applied Chemistry; The University of Tokyo; 7-3-1 Hongo Bunkyo-ku Tokyo 113-8656 Japan
| | - Vincent Duplan
- Department of Applied Chemistry; The University of Tokyo; 7-3-1 Hongo Bunkyo-ku Tokyo 113-8656 Japan
| | - Manabu Hoshino
- Department of Applied Chemistry; The University of Tokyo; 7-3-1 Hongo Bunkyo-ku Tokyo 113-8656 Japan
| | - Makoto Fujita
- Department of Applied Chemistry; The University of Tokyo; 7-3-1 Hongo Bunkyo-ku Tokyo 113-8656 Japan
| | - Elena Fernández
- Department Quimica Física i Inorgànica; University Rovira i Virgili; C/Marcel⋅lí Domingo s/n 43007 Tarragona Spain
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14
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Perras FA. Quantitative structure parameters from the NMR spectroscopy of quadrupolar nuclei. PURE APPL CHEM 2016. [DOI: 10.1515/pac-2015-0801] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractNuclear magnetic resonance (NMR) spectroscopy is one of the most important characterization tools in chemistry, however, 3/4 of the NMR active nuclei are underutilized due to their quadrupolar nature. This short review centers on the development of methods that use solid-state NMR of quadrupolar nuclei for obtaining quantitative structural information. Namely, techniques using dipolar recoupling as well as the resolution afforded by double-rotation are presented for the measurement of spin–spin coupling between quadrupoles, enabling the measurement of internuclear distances and connectivities. Two-dimensional J-resolved-type experiments are then presented for the measurement of dipolar and J coupling, between spin-1/2 and quadrupolar nuclei as well as in pairs of quadrupolar nuclei. Select examples utilizing these techniques for the extraction of structural information are given. Techniques are then described that enable the fine refinement of crystalline structures using solely the electric field gradient tensor, measured using NMR, as a constraint. These approaches enable the solution of crystal structures, from polycrystalline compounds, that are of comparable quality to those solved using single-crystal diffraction.
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Affiliation(s)
- Frédéric A. Perras
- 1Ames Laboratory, Iowa State University, 211 Spedding Hall, Ames, IA 50011-3020, USA
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Xu Y, Southern SA, Szell PMJ, Bryce DL. The role of solid-state nuclear magnetic resonance in crystal engineering. CrystEngComm 2016. [DOI: 10.1039/c6ce01206j] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
This Highlight article discusses the role of solid-state NMR spectroscopy in crystal engineering with the aid of several examples from the literature.
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Affiliation(s)
- Yijue Xu
- Department of Chemistry and Biomolecular Sciences
- University of Ottawa
- Ottawa, Ontario K1N6N5 Canada
| | - Scott A. Southern
- Department of Chemistry and Biomolecular Sciences
- University of Ottawa
- Ottawa, Ontario K1N6N5 Canada
| | - Patrick M. J. Szell
- Department of Chemistry and Biomolecular Sciences
- University of Ottawa
- Ottawa, Ontario K1N6N5 Canada
| | - David L. Bryce
- Department of Chemistry and Biomolecular Sciences
- University of Ottawa
- Ottawa, Ontario K1N6N5 Canada
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Dewhurst RD, Neeve EC, Braunschweig H, Marder TB. sp(2)-sp(3) diboranes: astounding structural variability and mild sources of nucleophilic boron for organic synthesis. Chem Commun (Camb) 2015; 51:9594-607. [PMID: 25912808 DOI: 10.1039/c5cc02316e] [Citation(s) in RCA: 202] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Despite the widespread use of organoborane reagents in organic synthesis and catalysis, a major challenge still remains: very few boron-centered nucleophiles exist for the direct construction of B-C bonds. Perhaps the most promising emerging solution to this problem is the use of sp(2)-sp(3) diboranes, in which one boron atom of a conventional diborane(4) is quaternised by either a neutral or anionic nucleophile. These compounds, either isolated or generated in situ, serve as relatively mild and convenient sources of the boryl anion [BR2](-) for use in organic synthesis and have already proven their efficacy in metal-free as well as metal-catalysed borylation reactions. This Feature article documents the history of sp(2)-sp(3) diborane synthesis, their properties and surprising structural variability, and their burgeoning utility in organic synthesis.
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Affiliation(s)
- Rian D Dewhurst
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
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Pietsch S, Paul U, Cade IA, Ingleson MJ, Radius U, Marder TB. Room temperature ring expansion of N-heterocyclic carbenes and B-B bond cleavage of diboron(4) compounds. Chemistry 2015; 21:9018-21. [PMID: 25960171 DOI: 10.1002/chem.201501498] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Indexed: 11/06/2022]
Abstract
We report the isolation and detailed structural characterization, by solid-state and solution NMR spectroscopy, of the neutral mono- and bis-NHC adducts of bis(catecholato)diboron (B2 cat2 ). The bis-NHC adduct undergoes thermally induced rearrangement, forming a six-membered -B-C=N-C=C-N-heterocyclic ring via C-N bond cleavage and ring expansion of the NHC, whereas the mono-NHC adduct is stable. Bis(neopentylglycolato)diboron (B2 neop2 ) is much more reactive than B2 cat2 giving a ring expanded product at room temperature, demonstrating that ring expansion of NHCs can be a very facile process with significant implications for their use in catalysis.
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Affiliation(s)
- Sabrina Pietsch
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg (Germany)
| | - Ursula Paul
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg (Germany)
| | - Ian A Cade
- School of Chemistry, The University of Manchester, Manchester M13 9PL (UK)
| | - Michael J Ingleson
- School of Chemistry, The University of Manchester, Manchester M13 9PL (UK).
| | - Udo Radius
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg (Germany).
| | - Todd B Marder
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg (Germany).
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Abstract
This article describes some highlights of the research which has been carried out in my laboratory at the University of Ottawa over the period covering 2005 to 2014. My research is in the general areas of solid-state NMR, applications of quantum chemistry, and biomolecular NMR. The format will follow that of my 2014 Canadian Society for Chemistry Keith Laidler Award presentation given in Vancouver in June 2014 at the 97th Canadian Chemistry Conference and Exhibition. Following a brief introduction, I will present some of our most interesting and exciting recent advances according to the following six themes: 1. Fundamental solid-state NMR. 2. Materials characterization and NMR crystallography. 3. Pharmaceuticals and polymorphism. 4. Non-covalent interactions: Halogen bonds. 5. Biomolecular NMR. 6. Software development.
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Affiliation(s)
- David L. Bryce
- Department of Chemistry, University of Ottawa, Ottawa, ON K1N 6N5, Canada
- Department of Chemistry, University of Ottawa, Ottawa, ON K1N 6N5, Canada
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Perras FA, Ewing WC, Dellermann T, Böhnke J, Ullrich S, Schäfer T, Braunschweig H, Bryce DL. Spying on the boron-boron triple bond using spin-spin coupling measured from 11B solid-state NMR spectroscopy. Chem Sci 2015; 6:3378-3382. [PMID: 29142694 PMCID: PMC5657093 DOI: 10.1039/c5sc00644a] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 03/31/2015] [Indexed: 11/21/2022] Open
Abstract
Boron–boron J coupling constants provide new insight into the nature of the boron–boron triple bond.
There is currently tremendous interest in the previously documented example of a stable species exhibiting a boron–boron triple bond (Science, 2012, 336, 1420). Notably, it has recently been stated using arguments based on force constants that this diboryne may not, in reality, feature a boron–boron triple bond. Here, we use advanced solid-state NMR and computational methodology in order to directly probe the orbitals involved in multiple boron–boron bonds experimentally via analysis of 11B–11B spin–spin (J) coupling constants. Computationally, the mechanism responsible for the boron–boron spin–spin coupling in these species is found to be analogous to that for the case of multiply-bonded carbon atoms. The trend in reduced J coupling constants for diborenes and a diboryne, measured experimentally, is in agreement with that known for alkenes and alkynes. This experimental probe of the electronic structure of the boron–boron multiple bond provides strong evidence supporting the originally proposed nature of the bonds in the diboryne and diborenes, and demonstrates that the orbitals involved in boron–boron bonding are equivalent to those well known to construct the multiple bonds between other second-row elements such as carbon and nitrogen.
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Affiliation(s)
- Frédéric A Perras
- Department of Chemistry and CCRI , University of Ottawa , 10 Marie Curie Pvt. D'Iorio Hall , Ottawa , Ontario K1N6N5 , Canada .
| | - William C Ewing
- Institut für Anorganische Chemie , Julius-Maximilians-Universität Würzburg , Am Hubland , 97074 , Germany .
| | - Theresa Dellermann
- Institut für Anorganische Chemie , Julius-Maximilians-Universität Würzburg , Am Hubland , 97074 , Germany .
| | - Julian Böhnke
- Institut für Anorganische Chemie , Julius-Maximilians-Universität Würzburg , Am Hubland , 97074 , Germany .
| | - Stefan Ullrich
- Institut für Anorganische Chemie , Julius-Maximilians-Universität Würzburg , Am Hubland , 97074 , Germany .
| | - Thomas Schäfer
- Institut für Anorganische Chemie , Julius-Maximilians-Universität Würzburg , Am Hubland , 97074 , Germany .
| | - Holger Braunschweig
- Institut für Anorganische Chemie , Julius-Maximilians-Universität Würzburg , Am Hubland , 97074 , Germany .
| | - David L Bryce
- Department of Chemistry and CCRI , University of Ottawa , 10 Marie Curie Pvt. D'Iorio Hall , Ottawa , Ontario K1N6N5 , Canada .
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Cade IA, Chau WY, Vitorica-Yrezabal I, Ingleson MJ. 1,1/1,2 Isomerisation in Lewis base adducts of B2cat2. Dalton Trans 2015; 44:7506-11. [DOI: 10.1039/c5dt00645g] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The unexpected 1,1/1,2 isomerisation of the diolate in B2cat2 is observed on addition of Lewis bases.
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Affiliation(s)
- I. A. Cade
- School of Chemistry
- The University of Manchester
- Manchester
- UK
| | - W. Y. Chau
- School of Chemistry
- The University of Manchester
- Manchester
- UK
| | | | - M. J. Ingleson
- School of Chemistry
- The University of Manchester
- Manchester
- UK
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Perras FA, Bryce DL. Direct Characterization of Metal-Metal Bonds between Nuclei with Strong Quadrupolar Interactions via NMR Spectroscopy. J Phys Chem Lett 2014; 5:4049-4054. [PMID: 26276493 DOI: 10.1021/jz5023448] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Metal-metal bonds can be difficult to characterize directly. We demonstrate that J couplings between metal nuclei experiencing strong quadrupolar interactions can be easily measured from well-defined splittings in NMR spectra of powdered samples. Using (69/71)Ga NMR, it is shown that homonuclear J coupling, which is four orders of magnitude smaller than the quadrupolar coupling in a series of compounds featuring gallium-gallium bonds, can be extracted with a 2-D NMR experiment. The dependence of the multiplets on crystal symmetry reveals information on the structures of two Ga-Ga-bonded compounds for which diffraction data are unavailable. Interpretation of the data in a molecular orbital framework provides insight into the nature of the metal-metal bond.
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Affiliation(s)
- Frédéric A Perras
- Department of Chemistry and CCRI, University of Ottawa, 10 Marie Curie Pvt. D'Iorio Hall, Ottawa, Ontario K1N6N5, Canada
| | - David L Bryce
- Department of Chemistry and CCRI, University of Ottawa, 10 Marie Curie Pvt. D'Iorio Hall, Ottawa, Ontario K1N6N5, Canada
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Perras FA, Bryce DL. Theoretical study of homonuclear J coupling between quadrupolar spins: single-crystal, DOR, and J-resolved NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 242:23-32. [PMID: 24594753 DOI: 10.1016/j.jmr.2014.01.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 01/12/2014] [Accepted: 01/20/2014] [Indexed: 06/03/2023]
Abstract
The theory describing homonuclear indirect nuclear spin-spin coupling (J) interactions between pairs of quadrupolar nuclei is outlined and supported by numerical calculations. The expected first-order multiplets for pairs of magnetically equivalent (A2), chemically equivalent (AA'), and non-equivalent (AX) quadrupolar nuclei are given. The various spectral changeovers from one first-order multiplet to another are investigated with numerical simulations using the SIMPSON program and the various thresholds defining each situation are given. The effects of chemical equivalence, as well as quadrupolar coupling, chemical shift differences, and dipolar coupling on double-rotation (DOR) and J-resolved NMR experiments for measuring homonuclear J coupling constants are investigated. The simulated J coupling multiplets under DOR conditions largely resemble the ideal multiplets predicted for single crystals, and a characteristic multiplet is expected for each of the A2, AA', and AX cases. The simulations demonstrate that it should be straightforward to distinguish between magnetic inequivalence and equivalence using J-resolved NMR, as was speculated previously. Additionally, it is shown that the second-order quadrupolar-dipolar cross-term does not affect the splittings in J-resolved experiments. Overall, the homonuclear J-resolved experiment for half-integer quadrupolar nuclei is demonstrated to be robust with respect to the effects of first- and second-order quadrupolar coupling, dipolar coupling, and chemical shift differences.
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Affiliation(s)
- Frédéric A Perras
- Department of Chemistry and Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie Private, Ottawa, Ontario K1N 6N5, Canada
| | - David L Bryce
- Department of Chemistry and Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie Private, Ottawa, Ontario K1N 6N5, Canada.
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Perras FA, Bryce DL. Boron–boron J coupling constants are unique probes of electronic structure: a solid-state NMR and molecular orbital study. Chem Sci 2014. [DOI: 10.1039/c4sc00603h] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
J couplings measured between 11B spin pairs in solid diboron compounds provide insight into electronic structure and crystallographic symmetry.
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Affiliation(s)
- Frédéric A. Perras
- Department of Chemistry and Centre for Catalysis Research and Innovation
- University of Ottawa
- Ottawa, Canada
| | - David L. Bryce
- Department of Chemistry and Centre for Catalysis Research and Innovation
- University of Ottawa
- Ottawa, Canada
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Brinkmann A, Edén M. Central-transition double-quantum sideband NMR spectroscopy of half-integer quadrupolar nuclei: estimating internuclear distances and probing clusters within multi-spin networks. Phys Chem Chem Phys 2014; 16:7037-50. [DOI: 10.1039/c4cp00029c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Clusters within quadrupolar spin networks are probed and internuclear distances between quadrupolar nuclei are estimated by central-transition double-quantum sideband NMR spectroscopy.
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Affiliation(s)
- Andreas Brinkmann
- Measurement Science and Standards
- National Research Council Canada
- Ottawa, Canada
| | - Mattias Edén
- Physical Chemistry Division
- Department of Materials and Environmental Chemistry
- Arrhenius Laboratory
- Stockholm University
- 106 91 Stockholm, Sweden
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