Layered Tungsten Oxide-Based Hybrid Materials Incorporating Transition Metal Ions

2004 ◽  
Vol 847 ◽  
Author(s):  
Bridget Ingham ◽  
S. V. Chong ◽  
Jeff L. Tallon
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Tungsten Oxide ◽  
Hybrid Materials ◽  
Transition Metal Oxides ◽  
Metal Ion ◽  
Interlayer Spacing ◽  
Transition Metal Ions ◽  
Ferromagnetic Transition ◽  
Inorganic Framework

ABSTRACTLayered organic-inorganic hybrid materials based on tungsten oxide as the inorganic framework have been synthesised to include transition metal ions. The resulting materials have been characterised using a number of techniques. X-ray diffraction shows an interlayer expansion with increasing alkyl length. Infrared vibrational spectra of manganese tungstate compounds indicate the organic amine molecules are neutrally charged, and the inorganic framework is unaltered as one varies the organic intercalate. The magnetic behaviour of the materials has also been explored using a SQUID magnetometer. In the manganese tungstate hybrids an antiferromagnetic (AF) transition is observed, which decreases in temperature as the inorganic interlayer spacing is increased. A nickel tungstate hybrid sample, on the other hand, displays a ferromagnetic transition, which we attribute to a canted AF phase below 15 K. In all cases studied, the behaviour can be mapped to an effective moment (Peff) per transition metal ion, which agrees well with theoretical and literature values for other transition metal oxides.

scholarly journals Low-Dimensional Physics of Organic-Inorganic Multilayers

2021 ◽  
Author(s):  
◽  
Bridget Ingham
Keyword(s):  
Transition Metal ◽  
Metal Oxide ◽  
Metal Ions ◽  
Tungsten Oxide ◽  
Hybrid Materials ◽  
Transition Metal Ions ◽  
X Ray ◽  
Metal Tungstate ◽  
Low Dimensional ◽  
Inorganic Layers

<p>This thesis demonstrates the rich low-dimensional physics associated with the class of organic-inorganic hybrid materials based on atomic layers of a metal oxide separated by organic spacer molecules. Hybrid materials based on tungsten oxide and also transition metal tungstates (with manganese, iron, cobalt, nickel and copper) were synthesised and characterised using a variety of techniques. The materials in question represent one example of the huge variety of systems classed as 'organic-inorganic hybrids' and have the potential to combine the high-electron mobility of the metal oxide layers with the propensity for self-assembly of the organic layers. The crystal structures of the compounds were investigated using powder X-ray diffraction and electron diffraction, and compared with structural information obtained using IR, Raman, and extended X-ray absorption fine structure (EXAFS) spectroscopies. This data confirmed the presence of a 2- dimensional layered structure. The electronic properties of the hybrids were studied using optical spectroscopy and confirmed via ab initio calculations. The band gaps of the tungsten oxide hybrids were found to be independent of interlayer spacing, and in all cases were larger than that observed in the three dimensional WO3 'parent' material. For the transition metal tungstate hybrids there appeared to be significant interactions between the organic amines and the transition metal ions within the inorganic layers. The magnetic properties of the hybrids incorporating transition metal ions were also studied in detail. Many of these metal tungstate hybrids display magnetic transitions at low temperatures indicating a crossover from 2-dimensional to 3-dimensional behaviour. This illustrates the importance of the low-dimensional nature of the inorganic layers in these hybrid materials and thus their potential in nano-structural applications.</p>

scholarly journals Low-Dimensional Physics of Organic-Inorganic Multilayers

2021 ◽  
Author(s):  
◽  
Bridget Ingham
Keyword(s):  
Transition Metal ◽  
Metal Oxide ◽  
Metal Ions ◽  
Tungsten Oxide ◽  
Hybrid Materials ◽  
Transition Metal Ions ◽  
X Ray ◽  
Metal Tungstate ◽  
Low Dimensional ◽  
Inorganic Layers

<p>This thesis demonstrates the rich low-dimensional physics associated with the class of organic-inorganic hybrid materials based on atomic layers of a metal oxide separated by organic spacer molecules. Hybrid materials based on tungsten oxide and also transition metal tungstates (with manganese, iron, cobalt, nickel and copper) were synthesised and characterised using a variety of techniques. The materials in question represent one example of the huge variety of systems classed as 'organic-inorganic hybrids' and have the potential to combine the high-electron mobility of the metal oxide layers with the propensity for self-assembly of the organic layers. The crystal structures of the compounds were investigated using powder X-ray diffraction and electron diffraction, and compared with structural information obtained using IR, Raman, and extended X-ray absorption fine structure (EXAFS) spectroscopies. This data confirmed the presence of a 2- dimensional layered structure. The electronic properties of the hybrids were studied using optical spectroscopy and confirmed via ab initio calculations. The band gaps of the tungsten oxide hybrids were found to be independent of interlayer spacing, and in all cases were larger than that observed in the three dimensional WO3 'parent' material. For the transition metal tungstate hybrids there appeared to be significant interactions between the organic amines and the transition metal ions within the inorganic layers. The magnetic properties of the hybrids incorporating transition metal ions were also studied in detail. Many of these metal tungstate hybrids display magnetic transitions at low temperatures indicating a crossover from 2-dimensional to 3-dimensional behaviour. This illustrates the importance of the low-dimensional nature of the inorganic layers in these hybrid materials and thus their potential in nano-structural applications.</p>

HREM Study of electron-induced surface radiation damage in ReO3

1991 ◽  
Vol 49 ◽  
pp. 636-637
Author(s):  
R. Ai ◽  
H.-J. Fan ◽  
L. D. Marks
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Metal Oxides ◽  
Electron Irradiation ◽  
Transition Metal Oxides ◽  
Carbon Film ◽  
Transition Metal Ions ◽  
Surface Radiation ◽  
Valence Transition ◽  
Electron Microscopes

It has been known for a long time that electron irradiation induces damage in maximal valence transition metal oxides such as TiO2, V2O5, and WO3, of which transition metal ions have an empty d-shell. This type of damage is excited by electronic transition and can be explained by the Knoteck-Feibelman mechanism (K-F mechanism). Although the K-F mechanism predicts that no damage should occur in transition metal oxides of which the transition metal ions have a partially filled d-shell, namely submaximal valence transition metal oxides, our recent study on ReO3 shows that submaximal valence transition metal oxides undergo damage during electron irradiation.ReO3 has a nearly cubic structure and contains a single unit in its cell: a = 3.73 Å, and α = 89°34'. TEM specimens were prepared by depositing dry powders onto a holey carbon film supported on a copper grid. Specimens were examined in Hitachi H-9000 and UHV H-9000 electron microscopes both operated at 300 keV accelerating voltage. The electron beam flux was maintained at about 10 A/cm2 during the observation.

2,2î-Bipyridine Catalyzed Bleaching of Cotton Fibers with Peracetic Acid

1988 ◽  
Vol 58 (4) ◽  
pp. 198-210 ◽  
Author(s):  
James W. Rucker ◽  
David M. Cates
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Peracetic Acid ◽  
Metal Ion ◽  
Solution Treatment ◽  
Transition Metal Ions ◽  
Ferrous Ion ◽  
Cotton Fibers ◽  
Lauryl Sulfate ◽  
Ferrous Ions

Peracetic acid can be catalyzed to bleach cotton fibers at temperatures as low as 30°C by incorporating 2,2î-bipyridine in the bleach solution. Treatment of the fibers with HCl prior to bleaching reduces bleaching effectiveness by removing trace transition metal ions from the fibers. Sorption of individual ions (Cr+3 Mn+2, Fe+2, Fe+3 Co+2, Ni+2, Cu+2, and Zn+2) by HCl treated cotton fibers prior to bleaching indicates that the ferrous ion produces the greatest catalytic effect, and it is only effective when the metal ion is in the fiber as opposed to in solution. Ferrous ions in the fibers sorb 2,2î-bipyridine from solution to form the tris-2,2î-bipyridine ferrous ion complex that is associated with the fibers, and it is the trischelate associated with the fibers that catalyzes bleaching. The effects of pH, temperature, and concentrations of 2,2î-bipyridine, sodium lauryl sulfate, and transition metal ions (in the fibers and in solution) on bleaching effectiveness and peracetic acid decomposition have been studied, and a bleaching mechanism is proposed.

Intermediate-stage transition metal ion exchange in a zeolite X

1982 ◽  
Vol 35 (7) ◽  
pp. 1335 ◽  
Author(s):  
M Chatterjee ◽  
D Ganguli
Keyword(s):  
Ion Exchange ◽  
Transition Metal ◽  
Metal Ions ◽  
Metal Ion ◽  
Intermediate Stage ◽  
Transition Metal Ions ◽  
Zeolite X ◽  
Counter Ions ◽  
Metal Ion Exchange ◽  
Exchange Behaviour

The exchange behaviour of some divalent transition metal ions M2+ (Zn2+, Cu2+, Ni2+, Co2+, Mn2+) in a zeolite NaX (SiO2/Al2O3 2.75) was studied at intermediate stages before equilibrium. The equivalent counter ion supply in the solution, given by the equivalent ratio of the two counter ions 2M2+/Na+, was found to be critical in determining the saturation level of exchange. The series of relative abilities of exchange was very similar to the well known selectivity series at equilibrium. It is suggested that water exchange of the metal ions in solution could be one of the factors controlling the relative ease of ion exchange.

scholarly journals Possible Action of Transition Divalent Metal Ions at the Inter-Pentameric Interface of Inactivated Foot-and-Mouth Disease Virus Provide A Simple but Effective Approach to Enhance Stability

2021 ◽  
Author(s):  
Xuan Lin ◽  
Yanli Yang ◽  
Yanmin Song ◽  
Shuai Li ◽  
Xuan Zhang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Disease Virus ◽  
Specific Antibody ◽  
Metal Ion ◽  
Foot And Mouth Disease ◽  
Transition Metal Ions ◽  
Mouth Disease ◽  
Transition Metal Ion ◽  
Mouth Disease Virus

The structural instability of inactivated foot-and-mouth disease virus (FMDV) hinders the development of vaccine industry. Here we found that some transition metal ions like Cu2+ and Ni2+ could specifically bind to FMDV capsids at capacities about 7089 and 3448 metal ions per capsid, respectively. These values are about 33- and 16-folds of the binding capacity of non-transition metal ion Ca2+ (about 214 per capsid). Further thermodynamic studies indicated that all these three metal ions bound to the capsids in spontaneous enthalpy driving manners (ΔG<0, ΔH<0, ΔS<0), and the Cu2+ binding had the highest affinity. The binding of Cu2+ and Ni2+ could enhance both the thermostability and acid-resistant stability of capsids, while the binding of Ca2+ was helpful only to the thermostability of the capsids. Animal experiments showed that the immunization of FMDV bound with Cu2+ induced the highest specific antibody titers in mice. Coincidently, the FMDV bound with Cu2+ exhibited significantly enhanced affinities to integrin β6 and heparin sulfate, both of which are important cell surface receptors for FMDV attaching. Finally, the specific interaction between capsids and Cu2+ or Ni2+ was applied to direct purification of FMDV from crude cell culture feedstock by the immobilized metal affinity chromatography. Based on our new findings and structural analysis of the FMDV capsid, a “transition metal ion bridges” mechanism that describes linkage between adjacent histidine and other amino acids at the inter-pentameric interface of the capsids by transition metal ions coordination action was proposed to explain their stabilizing effect imposed on the capsid. IMPORTANCE How to stabilize the inactivated FMDV without affecting virus infectivity and immunogenicity is a big challenge in vaccine industry. The electrostatic repulsion induced by protonation of a large amount of histidine residues at the inter-pentameric interface of viral capsids is one of the major mechanisms causing the dissociation of capsids. In the present work, this structural disadvantage inspired us to stabilize the capsids through coordinating transition metal ions with the adjacent histidine residues in FMDV capsid, instead of removing or substituting them. This approach was proved effective to enhance not only the stability of FMDV, but also enhance the specific antibody responses; thus, providing a new guideline for designing an easy-to-use strategy suitable for large-scale production of FMDV vaccine antigen.

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