Mesoporous hybrid materials containing two transition metal ions, one in the framework, the other in the channel pores

2003 ◽  
pp. 1564-1565 ◽  
Author(s):  
Robert J. P. Corriu ◽  
Ahmad Mehdi ◽  
Catherine Reyé ◽  
Chloé Thieuleux
2004 ◽  
Vol 847 ◽  
Author(s):  
Bridget Ingham ◽  
S. V. Chong ◽  
Jeff L. Tallon

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.


2021 ◽  
Author(s):  
◽  
Bridget Ingham

<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>


RSC Advances ◽  
2019 ◽  
Vol 9 (21) ◽  
pp. 11932-11938 ◽  
Author(s):  
Yingying Wu ◽  
Xuefei Li ◽  
Ying Liu ◽  
Ge Xiao ◽  
Yijiao Huang ◽  
...  

Three novel inorganic–organic hybrid materials based on 2,6-bis(1,2,4-triazol-1-yl)pyridine have been synthesized with different polyanions and transition metal ions.


2021 ◽  
Author(s):  
◽  
Bridget Ingham

<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>


1963 ◽  
Vol 16 (3) ◽  
pp. 371 ◽  
Author(s):  
GJ Sutton

The following complexes of the chelating ligands 2-methyl-6-aminomethylpyridine (6-methyl-2-picolylamine or mepic) and 2-thioamidopyridine (thiopic) have been prepared and studied: [Cu mepic2X]X, where X = Cl, Br, I, NO3, ClO4, [Cu mepic2C2O4], [Ni mepic3][ClO4]2, [M(II) thiopic3][ClO4]2, [M(III) thiopic3][ClO4]3, (M(II) = Co, Ni; M(III) = CO, Fe), and [Co thiopic3]Cl2. Conductance measurements in ethanol, nitromethane, and nitrobenzene indicate that the [Cu mepic2X]X complexes are 5-covalent whilst the other complexes studied are 6-covalent. All the complexes are "spin free" excepting those of Co(III). Absorption spectra of the copper complexes in the near ultraviolet region were also made.


1987 ◽  
Vol 52 (10) ◽  
pp. 2451-2456 ◽  
Author(s):  
Petr Sedlák ◽  
Stanislav Luňák ◽  
Pavel Lederer

Quantum yields of hydrogen peroxide photolysis and photoinitiated hydroxylation of 2-hydroxybenzoic acid in the presence of 3d transition metal ions have been measured. Marked photocatalytic effects were only observed for Cu(II) in hydrogen peroxide photolysis, and for Fe(III) in photoinitiated hydroxylation of 2-hydroxybenzoic acid. No photocatalytic activity was detected for the other 3d transition metal ions investigated. Fe(III) and Cu(II) differ in their photocatalytic activities, suggesting that the simple concept of free OH. radical formation cannot explain the mechanisms of their action.


Author(s):  
R. Ai ◽  
H.-J. Fan ◽  
L. D. Marks

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.


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