scholarly journals Synthetic Approaches to the Incorporation of Gallium and Germanium into Inorganic Polymer Structures

2021 ◽  
Author(s):  
◽  
Andrew Timothy Durant
Keyword(s):  
Solid State ◽  
Sol Gel ◽  
Mas Nmr ◽  
Inorganic Polymer ◽  
Magic Angle ◽  
29Si Nmr ◽  
Inorganic Polymers ◽  
X Ray ◽  
27Al Mas Nmr ◽  
Potassium Germanate

<p>New sol-gel and solid-state synthesis methods and combinations of these were developed for the preparation of several new inorganic polymers related to aluminosilicate inorganic polymers, attempting to substitute gallium and germanium for aluminium and silicon. Gallium could successfully substitute for aluminium, but germanium could not be substituted for silicon by these methods. Gallium silicate and gallium aluminosilicate inorganic polymers were synthesised from mixtures of KGaO2, KAlO2, KOH solutions with finely divided SiO2 (silica fume) using a combination of sol-gel and solid-state techniques. The products of these reactions were studied by X-ray powder diffraction (XRD), solid-state 27Al, 29Si, 71Ga and 39K nuclear magnetic resonance with magic-angle spinning (MAS NMR) and scanning electron microscopy (SEM). For the synthesis of these mixed gallium-aluminium silicate inorganic polymers, the optimal SiO2:(Ga2O3+Al2O3) ratio was found to be 7 and the Ga:Al ratio could range from 100% Ga to 100% Al, with all intermediate ratios yielding inorganic polymers. The products showed all the characteristics of a true inorganic polymer, being X-ray amorphous and containing gallium and/or aluminium in tetrahedral coordination states. 29Si MAS NMR showed the occurrence of Si(3Ga) and Si(2Ga) sites when gallium was present, and Si(3Al) and Si(2Al) sites when aluminium was present. Unreacted silica was also detected in these compounds by 29Si NMR and spherical silica particles were observed by SEM. Heat treatment of gallium silicate, gallium aluminosilicate and aluminosilicate inorganic polymers synthesised by variations of the sol-gel method was monitored by thermal analysis methods (DSC-TGA) which revealed a water loss at 75 [degrees]C and 160 [degrees]C followed by a phase transition at 950 [degrees]C. At this temperature the inorganic polymers crystallised to KGaSi2O6 and KAlSi2O6. The thermal behaviour of these samples was found to be different at 1200 [degrees]C; the high-temperature products derived from the gallium silicate inorganic polymers remained as crystalline KGaSi2O6 and retained their shape, while gallium aluminosilicate and aluminosilicate inorganic polymers melted and slumped, losing their shape and becoming X-ray amorphous. Attempts to substitute germanium for silicon in the inorganic polymer structure were unsuccessful. A sol-gel approach using GeO2 produced crystalline K6Ga6(GeO4)6(H2O)7. In an alternative solid-state approach, potassium germanate was synthesised and subsequently reacted with KGaO2 in a solidstate reaction to form partially amorphous hydraulic precursors; however, these did not set on the addition of water. A solid-state reaction of potassium germanate with KGa5O8 formed a partially amorphous precursor powder that set with the addition of water. However, the cured product was not amorphous, but proved to be crystalline K6Ga6(GeO4)6(H2O)7. In another approach, a sol-gel reaction of NaAlO2 solution and GeO2 with KOH solution set to an X-ray amorphous but brittle product. 27Al MAS NMR showed this to contain aluminium in both tetrahedral and octahedral coordination states. When KAlO2 was used instead of NaAlO2, the products were crystalline. The study of the structure of these germanium compounds is hindered by the inaccessibility of the germanium nuclide to MAS NMR. Nevertheless, the ability to synthesise a new category of materials by these new methods opens up the possibility of their potential applications as fluorescent materials and as components of optoelectronic devices.</p>

scholarly journals Synthetic Approaches to the Incorporation of Gallium and Germanium into Inorganic Polymer Structures

2021 ◽  
Author(s):  
◽  
Andrew Timothy Durant
Keyword(s):  
Solid State ◽  
Sol Gel ◽  
Mas Nmr ◽  
Inorganic Polymer ◽  
Magic Angle ◽  
29Si Nmr ◽  
Inorganic Polymers ◽  
X Ray ◽  
27Al Mas Nmr ◽  
Potassium Germanate

<p>New sol-gel and solid-state synthesis methods and combinations of these were developed for the preparation of several new inorganic polymers related to aluminosilicate inorganic polymers, attempting to substitute gallium and germanium for aluminium and silicon. Gallium could successfully substitute for aluminium, but germanium could not be substituted for silicon by these methods. Gallium silicate and gallium aluminosilicate inorganic polymers were synthesised from mixtures of KGaO2, KAlO2, KOH solutions with finely divided SiO2 (silica fume) using a combination of sol-gel and solid-state techniques. The products of these reactions were studied by X-ray powder diffraction (XRD), solid-state 27Al, 29Si, 71Ga and 39K nuclear magnetic resonance with magic-angle spinning (MAS NMR) and scanning electron microscopy (SEM). For the synthesis of these mixed gallium-aluminium silicate inorganic polymers, the optimal SiO2:(Ga2O3+Al2O3) ratio was found to be 7 and the Ga:Al ratio could range from 100% Ga to 100% Al, with all intermediate ratios yielding inorganic polymers. The products showed all the characteristics of a true inorganic polymer, being X-ray amorphous and containing gallium and/or aluminium in tetrahedral coordination states. 29Si MAS NMR showed the occurrence of Si(3Ga) and Si(2Ga) sites when gallium was present, and Si(3Al) and Si(2Al) sites when aluminium was present. Unreacted silica was also detected in these compounds by 29Si NMR and spherical silica particles were observed by SEM. Heat treatment of gallium silicate, gallium aluminosilicate and aluminosilicate inorganic polymers synthesised by variations of the sol-gel method was monitored by thermal analysis methods (DSC-TGA) which revealed a water loss at 75 [degrees]C and 160 [degrees]C followed by a phase transition at 950 [degrees]C. At this temperature the inorganic polymers crystallised to KGaSi2O6 and KAlSi2O6. The thermal behaviour of these samples was found to be different at 1200 [degrees]C; the high-temperature products derived from the gallium silicate inorganic polymers remained as crystalline KGaSi2O6 and retained their shape, while gallium aluminosilicate and aluminosilicate inorganic polymers melted and slumped, losing their shape and becoming X-ray amorphous. Attempts to substitute germanium for silicon in the inorganic polymer structure were unsuccessful. A sol-gel approach using GeO2 produced crystalline K6Ga6(GeO4)6(H2O)7. In an alternative solid-state approach, potassium germanate was synthesised and subsequently reacted with KGaO2 in a solidstate reaction to form partially amorphous hydraulic precursors; however, these did not set on the addition of water. A solid-state reaction of potassium germanate with KGa5O8 formed a partially amorphous precursor powder that set with the addition of water. However, the cured product was not amorphous, but proved to be crystalline K6Ga6(GeO4)6(H2O)7. In another approach, a sol-gel reaction of NaAlO2 solution and GeO2 with KOH solution set to an X-ray amorphous but brittle product. 27Al MAS NMR showed this to contain aluminium in both tetrahedral and octahedral coordination states. When KAlO2 was used instead of NaAlO2, the products were crystalline. The study of the structure of these germanium compounds is hindered by the inaccessibility of the germanium nuclide to MAS NMR. Nevertheless, the ability to synthesise a new category of materials by these new methods opens up the possibility of their potential applications as fluorescent materials and as components of optoelectronic devices.</p>

X-ray diffraction and solid-state 119Sn CP-MAS NMR studies of some triaryltin(IV) chlorides

2003 ◽  
Vol 81 (11) ◽  
pp. 1187-1195 ◽  
Author(s):  
Jordan M Geller ◽  
Ian S Butler ◽  
Denis FR Gilson ◽  
Frederick G Morin ◽  
Ivor Wharf ◽  
...  
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Spin Coupling ◽  
Magic Angle ◽  
X Ray ◽  
Tin Chloride ◽  
Angle Spinning ◽  
Spin Spin Coupling

The solid-state 119Sn cross-polarization (CP) magic angle spinning (MAS) NMR spectra of a series of triaryltin chlorides of the form Ar3SnCl have been acquired. The indirect spin-spin coupling constants (J(119Sn-35Cl)), quadrupolar-dipolar shifts (d(119Sn-35Cl)), and the 119Sn chemical shift tensors were extracted. For the spectrum of triphenyltin chloride (I) the validity of the first-order perturbation approximation was tested by comparing results of both the perturbation and cubic-equation approaches and a variable-temperature NMR study undertaken to investigate the influence of the previously reported molecular motion in the solid. The X-ray crystal structures of the tris(o-tolyl)tin chloride (II) and tris(p-tolyl)tin chloride (IV) complexes have been examined. They belong to the monoclinic and triclinic space groups P21/n and P[Formula: see text], respectively, which are different from the previously reported tris(m-tolyl)tin chloride (III) complex, which crystallizes in the space group R3 and has threefold molecular symmetry. The structures and NMR properties of the complexes with meta-substituents are quite different from those with ortho- or para-substituents having axially symmetric shift tensors with small spans and larger J values.Key words: aryltin chlorides, magic angle spinning NMR, tin-chlorine spin-spin coupling, 119Sn chemical shift tensor, crystal structure.

scholarly journals Structural Characterizations of Aluminosilicates in Two Types of Fly Ash Samples from Shanxi Province, North China

Minerals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 358 ◽  
Author(s):  
Yunxia Liu ◽  
Fangui Zeng ◽  
Beilei Sun ◽  
Peng Jia ◽  
Ian T. Graham
Keyword(s):  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Aluminosilicate Glass ◽  
Shanxi Province ◽  
Infrared Spectrometry ◽  
Magic Angle ◽  
Xps Spectra ◽  
X Ray ◽  
27Al Mas Nmr ◽  
Two Samples

In order to determine the structural characterization of aluminosilicates in two types of fly ashes, two samples from Shanxi Province, China were selected for study. One was from a pulverized coal boiler (FA-1), and the other from a circulating fluidized bed boiler (FA-2). FA-1 had a much higher content of silicon dioxide (SiO2) (70.30%) than FA-2(42.19%), but aluminum oxide (Al2O3) was higher in FA-2 (25.41%) than in FA-1 (17.04%). The characterizations were investigated using various methods including X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), magic angle spinning nuclear magnetic resonance (MAS–NMR) spectrometry, and X-ray photoelectron spectroscopy (XPS). The XRD analysis showed that FA-1 contained aluminosilicate glass, quartz and mullite, while FA-2 contained significant amounts of amorphous aluminosilicate, quartz and gypsum. The FTIR results showed an increased substitution of Al3+ for Si4+ as the band of asymmetric stretching vibrations Si–O(Si) (1100 cm−1) moved to 1090 cm−1 for FA-2, much lower than for FA-1(1097 cm−1). Moreover, the sharpness of the bands in the 1250–1000 cm−1 region for FA-2 indicates that the silicate structure of FA-2 was more ordered than for FA-1. It can be understood from the 29Si MAS–NMR results that Q4(mAl) (Q4 are connected via 4 bridging O atoms to mAl) is the main structural type in FA-1 and FA-2, and that FA-2 contains more Al, which substitutes for Si in the Q4 structure. 27Al MAS–NMR demonstrated that a combination of tetrahedral, pentahedral, and octahedral Al existed in FA-1 and FA-2. The Si 2p XPS spectra suggested that there were three forms of Si, including bridging Si (Si–O2), non–bridging Si (Si–O), and SiO2 gel. The content of Si–O2 for FA-1 was 37.48% higher than Si–O (28.57%), while the content of Si–O2 was 30.21% lower than Si–O (40.15%) for FA-2. The Al 2p XPS spectra showed that octahedral Al was the dominant form for FA-1 with a content of 40.25%, while the main phase was tetrahedral Al for FA-2 with a proportion of 37.36%, which corresponds well with the 27Al MAS–NMR results.

scholarly journals Combination of solid state NMR and DFT calculation to elucidate the state of sodium in hard carbon electrodes

2016 ◽  
Vol 4 (34) ◽  
pp. 13183-13193 ◽  
Author(s):  
Ryohei Morita ◽  
Kazuma Gotoh ◽  
Mika Fukunishi ◽  
Kei Kubota ◽  
Shinichi Komaba ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Dft Calculation ◽  
Magic Angle Spinning ◽  
The State ◽  
Mas Nmr ◽  
Magic Angle ◽  
Multiple Quantum ◽  
Hard Carbon ◽  
Angle Spinning

We examined the state of sodium electrochemically inserted in HC prepared at 700–2000 °C using solid state Na magic angle spinning (MAS) NMR and multiple quantum (MQ) MAS NMR.

29Si NMR and XPS Investigation of the Structure of Silicon Oxycarbide Glasses Derived from Polysiloxane Precursors

1994 ◽  
Vol 346 ◽  
Author(s):  
R.J.P. Corriu ◽  
D. Leclercq ◽  
P.H. Mutin ◽  
A. Vioux
Keyword(s):  
Solid State ◽  
Photoelectron Spectroscopy ◽  
Solid State Nmr ◽  
Random Distribution ◽  
Silicon Oxycarbide ◽  
29Si Nmr ◽  
Xps Spectra ◽  
Excess Carbon ◽  
X Ray ◽  
Silicon Oxycarbide Glasses

ABSTRACTTwo silicon oxycarbide glasses with different compositions (O/Si ratio 1.2 and 1.8) were prepared by pyrolysis at moderate temperature (900 °C) of polysiloxane precursors. Their structure was investigated using quantitative 29Si solid-state NMR and X-ray photoelectron spectroscopy (XPS). The environment of the silicon atoms in the oxycarbide phase corresponded to a purely random distribution of Si-O and Si-C bonds depending on the O/Si ratio of the glass only and not on the structure of the precursors. At the light of the NMR results, the Si2p XPS spectra of the glasses may be interpreted using the contribution of the five possible SiOxC4-x tetrahedra. The Cls spectra of these glasses indicated the presence of oxycarbide carbon in CSi4 tetrahedra, similar to carbide carbon, and graphitic-like excess carbon.

Structural and Catalytic Properties of the Alkali Metal Ion-Exchanged Y-Zeolites by 29Si and 27Al Solid-State NMR and FT-IR Spectroscopy

2005 ◽  
Vol 277-279 ◽  
pp. 708-719
Author(s):  
Chang Seop Lee ◽  
Hee Jung Lee ◽  
Sung Woo Choi ◽  
Jahun Kwak ◽  
Charles H.F. Peden
Keyword(s):  
Solid State ◽  
Alkali Metal ◽  
Photoelectron Spectroscopy ◽  
Metal Ion ◽  
Nmr Spectra ◽  
Catalytic Properties ◽  
Nox Reduction ◽  
29Si Nmr ◽  
Y Zeolites ◽  
X Ray

A series of cation exchanged Y-zeolites were prepared by exchanging cations with various alkali (M+, M= Li, Na, K, Cs) metals. The structural and catalytic properties of the alkali metal exchanged Y-zeolites have been investigated by a number of analytical techniques. Comparative elemental analyses were determined by an Energy Dispersive Spectroscopy X-ray (EDS), X-ray Photoelectron Spectroscopy (XPS), Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) and X-ray Fluorescence (XRF) before and after cation substitution. The framework and non-framework Al coordination and the Si/Al ratios of the Y-zeolites were investigated by MAS Solid-State Nuclear Magnetic Resonance (NMR) spectroscopy. The Al NMR spectra were characterized by two 27Al resonance signals at 12 and 59 ppm, indicating the presence of the non-framework and framework Al respectively. The intensities of these resonances were used to monitor the amount of the framework and non-framework Al species in the series of exchanged zeolites. The 29Si NMR spectra were characterized by four resonance signals at -79, -84, -90, and -95 ppm. Changing the alkali metal cations in the exchanged Y-zeolites significantly altered the extent of the octahedral/tetrahedral coordination and the Si/Al ratio. The Fourier Transform Infrared spectra of the CO2 adsorbed on to the exchanged Y-zeolites showed a low frequency shift, as the atomic number of the exchanged alkali metal increased. In addition, the catalytic activity of these samples for NOx reduction were tested in combination with a non-thermal plasma technique and interpreted based on the above structural and spectroscopic information.

scholarly journals New Condensation Polymer Precursors Containing Consecutive Silicon Atoms—Decaisopropoxycyclopentasilane and Dodecaethoxyneopentasilane—And Their Sol–Gel Polymerization

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 841
Author(s):  
Sung Jin Park ◽  
Myong Euy Lee ◽  
Hyeon Mo Cho ◽  
Sangdeok Shim
Keyword(s):  
Solid State ◽  
Sol Gel ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Cross Polarization ◽  
Reaction Conditions ◽  
Polymer Precursors ◽  
Sol Gel Process ◽  
Angle Spinning ◽  
Magnetic Resonances

The sol–gel polymerization of alkoxysilanes is a convenient and widely used method for the synthesis of silicon polymers and silicon–organic composites. The development of new sol–gel precursors is very important for obtaining new types of sol–gel products. New condensation polymer precursors containing consecutive silicon atoms—decaisopropoxycyclopentasilane (CPS) and dodecaethoxyneopentasilane (NPS)—were synthesized for the preparation of polysilane–polysiloxane material. The CPS and NPS xerogels were prepared by the sol–gel polymerization of CPS and NPS under three reaction conditions (acidic, basic and neutral). The CPS and NPS xerogels were characterized using N2 physisorption measurements (Brunauer–Emmett–Teller; BET and Brunauer-Joyner-Halenda; BJH), solid-state CP/MAS (cross-polarization/magic angle spinning) NMRs (nuclear magnetic resonances), TEM, and SEM. Their porosity and morphology were strongly affected by the structure of the precursors, and partial oxidative cleavage of Si-Si bonds occurred during the sol–gel process. The new condensation polymer precursors are expected to expand the choice of approaches for new polysilane–polysiloxane.

ChemInform Abstract: X-Ray Diffraction, EPR, and 6Li and 27Al MAS NMR Study of LiAlO2-LiCoO2 Solid Solutions.

ChemInform ◽  
2010 ◽  
Vol 29 (17) ◽  
pp. no-no
Author(s):  
R. ALCANTARA ◽  
P. LAVELA ◽  
P. L. RELANO ◽  
J. L. TIRADO ◽  
E. ZHECHEVA ◽  
...  
Keyword(s):  
Solid Solutions ◽  
Mas Nmr ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nmr Study ◽  
27Al Mas Nmr
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