Intercalation metal

The intercalated catalysts can often be regarded as biomimetic oxidation catalysts. The intercalation of cationic metal complexes in the interlamellar space of clays often leads to increased catalytic activity and selectivity, due to the limited orientations by which the molecules are forced to accommodate themselves between sheets. The clays have electrostatic fields in their interlayer therefore, the intercalated metal complexes are more positively charged. Such complexes may show different behavior. For example, cationic Rh complexes catalyze the regioselective hydrogenation of carbonyl groups, whereas neutral complexes are not active.149 Cis-Alkenes are hydrogenated preferentially on bipyridyl-Pd(II) acetate intercalated in montmorillonite.150 The same catalyst was also used for the reduction of nitrobenzene.151... 

When using appropriate solvents for swelling of the interlayers, the intercalated metal ions are accessible to both substrates and catalysis. One of the first such demonstrations was also carried out with the Wilkinson complex for hydrogena-... 

Govindaraj A, Satishkumar BC, Nath M, Rao CNR (2000) Metal Nanowires and Intercalated Metal Layers in Single-Walled Carbon Nanotube Bundles. Chem Mater 12 202-205... 

Table 5.9. Ethylation of Benzene with Ethylene over Graphite-Intercalated Metal Halides187...

Table 5.22. Transethylation of Benzene with Diethylbenzene over Graphite-Intercalated Metal Halides.112...

E. Comparison of Intercalated and Externally Bound Viologens as Quenchers of an Intercalated Metal Complex... 

Figure 20 Schematic of the doubly modified duplex showing the most probable (50%) separation of the intercalated metal complexes. (Reproduced by permission of Ref. 327)...

Jamison found that low concentrations of intercalated copper or silver in niobium disulphides and diselenides promoted good lubricating performance. Higher concentrations increased the resistance to inter-lamellar shear, and therefore the friction, but improved high temperature performance due to the reduced intracrystalline shear and some sacrificial oxidation of the intercalated metals. 

Key Words boron nitride intercalation metallic oxidation. 

The approximately constant expansion of the graphite lattice, which is practically independent of the size of the intercalated metal atom, appears at first sight unusual for, in the ammonia-free compounds, the distance between the layer planes increases, as expected, with increasing size of the alkali metal atom from potassium to cesium. The constancy of the expansion for the ammoniates is perhaps attributable to the effect of the positions of the ammonia molecules in the lattice in determining the increase in the interplanar distance. If this were so, metal atoms or ions could perhaps find sufficient room in holes in the ammonia lattice. In support of this view it may be added that the expansion becomes greater if, in place of ammonia, a layer of amine such as methylamine or ethylamine is intercalated. 

Imides, lattice energies of, 196 Indenyl compounds, eighth-group elements and, 73,75 Intercalation, metal chlorides, graphite and, 254-259 metal oxides, graphite and, 260-262 metal sulfides, graphite and, 260-262 Intercalation compounds, graphite, comparative survey of, 263-264... 

Over TaS2 and intercalates MTa3Se (M = Fe, Co, Ni) cyclohexene (373-673 K) in hydrogen isomerized selectively to 1-methylcyclopentene and in nitrogen dehydrogenated to benzene. Intercalation of Fe and Ni increased activity without changing selectivity, but Co caused activity to decrease. The intercalated metals also decreased the rate of deactivation of the catalyst. 

F. Bedioui, Zeolite-encapsulated and Clay-intercalated Metal Porphyrin, Phthalocyanine and Schiff-base Complexes as Models for Biomimetic Oxidation Catalysts an Overview. Coord. Chem. Rev., 1995, 144, 39—68. 

Kittaka, S. Uchida, N. Kihara, T. Suetsugi, T. Sasaki, T. Interlayer water-molecules in vanadium pentoxide hydrate. 2. Effect of intercalated metal-ions on the adsorbability of water molecules.. Langmuir 1992, 8 (1), 45-48. 

Fig. 3 shows the XRD patterns after calcination of as prepared solids at 400 °C in Nz (M-4OO-N2). The disappearance of basal reflections at 20<1O deg suggests the lack of periodicity in the layer stacking. The products for M=Mn, Fe, and Zn exhibited diffraction peaks due to oxides of M, suggesting that part of intercalated metal acetates was precipitated as oxides. The Cu-400-Nz solely produced metallic precipitations in addition to anatase-type TiOz. FT-IR measurement confirmed the complete elimination of the organic components (vch 2840-2960 cm, Vco 1450. 1550 cm ) from these composites. As shown in Table 1, the BET surface areas of M-400-Nz were in the range of 23-100 m /g, compared to 11 m /g for pristine KzTi409 microcrystals. The largest surface area was attained by the Cr-400-Nz... 

Novel clay intercalated metal catalysts a study of the hydrogenation of styrene and 1-octene on clay intercalated Pd catalysts... 

The research on the catalytic applications of clay minerals has been the subject of considerable interest for some time [1-2]. On account of their lamellar structure, clays can be excellent host materials for various metals, and thus the precursors of clay intercalated metal catalysts [3]. This paper reports on the catalytic behaviour of novel Pd intercalated montmorillonites. 

The catalytic application of montmorillonites may either be related to their acidity [5-7], or their swelling properties [8-9], Swelling, induced by careful selection of both the reaction medium and interlayer cations, enables the reactant molecules to enter the interlamellar region and undergo catalytic reaction on interstitial active sites. Moreover, the layered structure of montmorillonite may induce a substrate selectivity depending on the reactant size. Therefore, clay intercalated metal catalysts offer potential applications in the preparation of fine chemicals. 

All the ternaries containing Bi, Sb and As, that have been synthesized and isolated are collected in Table 1. Numerous other phases have been observed, but always in admixture with other compounds, so these phases are not indicated in this table. It is important to emphasize that in every system the intercalated metallic sheets exhibit often various compositions and orderings. These are distinguished by greek letters in order of their respective thicknesses the thicker the intercalated sheet, the later the corresponding letter in the alphabet. In all these systems, the 2D and 6 -axis orderings of the intercalated sheets are generally complicated . Last, in the same table, the best synthesis conditions are indicated for every phase. 

Figure 3. Presentation of Ceo as anion in a charge transfer salt together with the famous cation tetrakis(dimethylamino)ethylene (a), and as an intercalated metallic compound (b).

The optical absorption spectra of intercalated 2H-M0S2 did not show appreciable changes on alkah metal intercalation up to concentrations of 30%, where a transition into a metallic phase at room temperature and a further transition into a superconductor at about 3-7 K was reported [139, 140]. Because the concentration of the intercalating metal atoms in the IF nanoparticles did not exceed 10%, no changes in the optical transmission spectra were anticipated nor were they found to occur. Also, the intercalation of alkah atoms in the IF particles induces n-type conductivity of the host. 

Bedioui, F. (1995). Zeohte-encapsulated and clay-intercalated metal porphyrin, phthalocyanine and Schiff-base complexes as models for biomimetic oxidation catalysts—an overview. Coord. Chem. Rev. 144, 39-68. 

The iron catalyst can also be assembled in situ. The Na+ form of fluorotetrasilicic mica was ion exchanged with Fe +, then the iron-modified clay was treated with a solution of a bis(imino)pyridine ligand in l-butanol.i Formation of the intercalated metal complexes was inferred by the appearance of the characteristic u(C = N) mode at 1588cm i and an increase in the basal spacing of the clay from 1.0 to 1.6nm for XXIII and XXIV. The bulkier XXII apparently did not form due to the inability of the ligand to penetrate the interlayer space. 

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