NMR Heteronuclear Correlation between Quadrupolar Nuclei in Solids

Iuga, Dinu; Morais, Cláudia; Gan, Zhehong; Neuville, Daniel R.; Cormier, Laurent; Massiot, Dominique

doi:10.1021/ja052452n

Cited by 152 publications

(161 citation statements)

References 26 publications

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“…The fraction of OAl 3 triclusters formed by tetrahedral Al alone is 14.5% for 50CaO glass and 9% for 64CaO glass in our models. These values are slightly higher than the values reported by Drewitt et al (18) for the liquid, and the NMR results for the 50CaO glass (13).…”

Section: Resultscontrasting

confidence: 63%

“…McMillan et al (12) performed 27 Al NMR measurements on CA glasses and found that Al 2 O 3 -poor composition glass has only fourfold coordinated Al atoms. Recent high-resolution NMR techniques (13) detected the formation of ∼5% OAl 3 triclusters (oxygen coordinating three Al atoms) in 50 mol % CaO-50 mol % Al 2 O 3 glass (50CaO glass), which are abundant in liquid Al 2 O 3 and may obstruct the vitrification process.…”

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confidence: 99%

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Network topology for the formation of solvated electrons in binary CaO–Al ₂ O ₃ composition glasses

Akola

Kohara

Ohara

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Glass formation in the CaO-Al 2 O 3 system represents an important phenomenon because it does not contain typical network-forming cations. We have produced structural models of CaO-Al 2 O 3 glasses using combined density functional theory-reverse Monte Carlo simulations and obtained structures that reproduce experiments (X-ray and neutron diffraction, extended X-ray absorption fine structure) and result in cohesive energies close to the crystalline ground states. The O-Ca and O-Al coordination numbers are similar in the eutectic 64 mol % CaO (64CaO) glass [comparable to 12CaO·7Al 2 O 3 (C12A7)], and the glass structure comprises a topologically disordered cage network with large-sized rings. This topologically disordered network is the signature of the high glass-forming ability of 64CaO glass and high viscosity in the melt. Analysis of the electronic structure reveals that the atomic charges for Al are comparable to those for Ca, and the bond strength of Al-O is stronger than that of Ca-O, indicating that oxygen is more weakly bound by cations in CaO-rich glass. The analysis shows that the lowest unoccupied molecular orbitals occurs in cavity sites, suggesting that the C12A7 electride glass [Kim SW, Shimoyama T, Hosono H (2011) Science 333(6038):71-74] synthesized from a strongly reduced high-temperature melt can host solvated electrons and bipolarons. Calculations of 64CaO glass structures with few subtracted oxygen atoms (additional electrons) confirm this observation. The comparable atomic charges and coordination of the cations promote more efficient elemental mixing, and this is the origin of the extended cage structure and hosted solvated (trapped) electrons in the C12A7 glass.amorphous network | glass topology | electron localization A ccording to the glass formation theories of Zachariasen and Sun, CaO-Al 2 O 3 (CA) liquids are unlikely to vitrify based on network and chemical bond strength considerations (1, 2). Al 2 O 3 does not typically act as a network former but can assist in glass formation, whereas Ca is usually a modifier with a high (>6) oxygen coordination number. A detailed understanding of the structure-electronic-property relations is important given that CA-based glasses have potential applications as infrared optics, windows, laser hosts (3), and photomemory materials (4-8). The C12A7 composition glass, in particular, has been found to be very important in synthesizing the stable electride glass from a strongly reduced high-temperature melt to form persistent solvated electrons (9, 10).CA has a narrow glass formation range around the eutectic composition of 64 mol % CaO-36 mol % Al 2 O 3 (64CaO glass) when one applies a conventional melt-quench method, although a wider range of 40-60 mol % CaO composition glass can be obtained by splat quench or containerless methods. McMillan and Piriou (11) carried out Raman spectroscopic measurements on CA glasses and crystals, and found that they comprise a fully polymerized network of AlO 4 units at 50 mol % composition. The polymerized network is d...

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Section: Resultscontrasting

confidence: 63%

mentioning

confidence: 99%

Network topology for the formation of solvated electrons in binary CaO–Al ₂ O ₃ composition glasses

Akola

Kohara

Ohara

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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“…Although connectivity of all three Al species to all three 31 P resonances was observed, the intensity of the crosspeaks show clear differences, reflecting the different magnitude of the J couplings. Recently, a modified J-HMQC experiment has been performed using the J coupling between two quadrupolar nuclei for the first time (178). This work used the J coupling between 27 Al and 17 O in crystalline CaAl 2 O 7 (grossite) with 30% 17 O enrichment and a glass, CaAl 2 O 4 , also with 30% 17 O enrichment.…”

Section: Concepts In Magnetic Resonancementioning

confidence: 99%

Structural information from quadrupolar nuclei in solid state NMR

Ashbrook

Duer

2006

Concepts Magnetic Resonance

146

262

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Solid-state NMR has become the method of choice for determining details of molecular-level structure in heterogeneous systems. Though spin-1/2 nuclei still form the core of most such studies, quadrupolar nuclei are increasingly being used. This review assesses what is currently possible, from achieving high-resolution spectra for quadrupolar nuclei (a prerequisite for most structure determination work), to forming correlation spectra which give qualitative details of spatial proximity of nuclei and the determination of internuclear distances, between quadrupolar spins and quadrupolar and spin-1/2 nuclei. Examples are given of each method discussed, and the advantages and disadvantages of the various experiments for different possible applications are assessed.

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“…As a through space interaction it means it only provides information on spatial proximity and not bonding. Indirect detection of coupling via INEPT of J-HMQC has allowed various connectivities in inorganic systems to be determined [36]. Correlation techniques for quadrupolar nuclei have been recently reviewed in…”

Section: Correlation Experimentsmentioning

confidence: 99%

Recent technique developments and applications of solid state NMR in characterising inorganic materials

Hanna

Smith

2010

Solid State Nuclear Magnetic Resonance

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A broad overview is given of some key recent developments in solid state NMR techniques that have driven enhanced applications to inorganic materials science. Reference is made to advances in hardware, pulse sequences and associated computational methods (e.g. first principles calculations, spectral simulation), along with their combination to provide more information about solid phases. The resulting methodology has allowed more nuclei to be observed and more structural information to be extracted. Cross referencing between experimental parameters and their calculation from the structure has seen an added dimension to NMR as a characterisation probe of materials. Emphasis is placed on the progress made in the last decade especially from those nuclei that were little studied previously. The general points about technique development and the increased range of nuclei observed are illustrated through a range of specific exemplars from inorganic materials science.

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NMR Heteronuclear Correlation between Quadrupolar Nuclei in Solids

Cited by 152 publications

References 26 publications

Network topology for the formation of solvated electrons in binary CaO–Al ₂ O ₃ composition glasses

Network topology for the formation of solvated electrons in binary CaO–Al ₂ O ₃ composition glasses

Structural information from quadrupolar nuclei in solid state NMR

Recent technique developments and applications of solid state NMR in characterising inorganic materials

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NMR Heteronuclear Correlation between Quadrupolar Nuclei in Solids

Cited by 152 publications

References 26 publications

Network topology for the formation of solvated electrons in binary CaO–Al 2 O 3 composition glasses

Network topology for the formation of solvated electrons in binary CaO–Al 2 O 3 composition glasses

Structural information from quadrupolar nuclei in solid state NMR

Recent technique developments and applications of solid state NMR in characterising inorganic materials

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Product

Resources

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Network topology for the formation of solvated electrons in binary CaO–Al ₂ O ₃ composition glasses

Network topology for the formation of solvated electrons in binary CaO–Al ₂ O ₃ composition glasses