Zeolite hosted

XRD patterns of the prepared samples V-Mo-Zeolite are similar to that of zeolites which suggests that the metal species (i.e. oxide, cations,...) are well dispersed through the zeolites structure and the absence of bulk phases in the XRD patterns implies that for these samples the molybdenum and vanadium oxides are present in either a nanocrystalline state or as a small crystallites which measured less than 4 nm in diameter. Furthermore, XRD and FTIR (1500-400 cm 1) showed no significant damage of the zeolite host structure after exchange and thermal treatment except for the sample V2MoMor. 

Regioselectivity is the preferential formation of one product over all other possibilities. The zeolite host effectively constrains separation of the secondary geminate radical pair A and B . 

The combination of dyes with microporous materials opens-up a way to develop selective chemosensors microporous zeolites with an anchored squaraine 27 (Fig. 13) and some other types of dyes can be used as chemosensors for the chromogenic discrimination of amines [75], These dye-zeolite hosts are expected to be promising sensor materials allowing the visible discrimination of selected target guests by size and/or polarity within families or closely related molecules. It was found that the response of the solid to amines was basically governed by the three-dimensional architecture of the solid material. 

At the time of maximum rate of hydrocarbon formation the composition of reaction product shows the pattern of a carbonium ion mechanism (much i-butane, i-pentane, Cg and Cy monomethyl paraffins, some aromatics and olefins C3, (Table 1). The zeolite hosts a large amount of non volatile hydrocarbons. 

Ship-in-Bottle Synthesis of Sterically Crowded Fe-Phthalocyanines in NaY Zeolite Hosts and Their Catalytic Behavior in Regioselective Oxidation of Alkanes... 

The zeolitic host was ion-exchanged to introduce the desired transition metal cation. Synthesis of the salen ligands in the mesopores was conducted at room temperature under an inert atmosphere. To the ion-exchanged zeolitic material, the optically pure diamine in dichloromethane was added, in slight excess (1.2 equiv.) relative to the metal content. The appropriate amount of aldehyde was added to the slurry. The final material was Soxhlet-extracted with dichloromethane and toluene, respectively, until the solvent remained colorless. This procedure is described elsewhere in detail [51]. 

The study of sorption of guests within zeolite hosts is complementary to the study of diffusion in zeolites. Having discussed the pathways and trajectories of molecules through micropores, we now consider the favored sorption locations, conformations of sorbates, and sorption energetics. Indeed, so close are the two subjects that they are frequently considered within the same paper. 

The configurational-bias Monte Carlo method (CB-MC) (112) was developed to overcome these sorts of problems. Instead of a random insertion into the zeolite host, the guest molecule is grown atom by atom within the host in a way that avoids unfavorable overlap with the zeolite atoms. 

TABLE 11 Dependence of Photoproduct Ratios from 97 on the Nature of Zeolite Hosts [290, 291[... 

Heinrichs, C. and Holderich, W.F. (1999) Novel zeolitic hosts for ship-in-a-bottle catalysts. Catal. Lett., 58, 75. 

To introduce the desired transition metal cation the zeolitic host was ion-exchanged. The synthesis of the salen ligands in the mesopores was conducted at room temperature under an inert atmosphere. To the ion-exchanged zeolitic material was added an amount... 

To evaluate the Van der Waals interaction energy in the case of our systems, we used the force field parameters provided by Deka et al., and defined to describe the aromatics adsorption within zeolites. The Van der Waals interaction is then computed between the aromatic guest and the zeolite host, and the DFT adsorption energy is corrected with this value as ... 

Zeolites are attractive host materials as they present regular channel systems, providing crystallographic defined locations for metal clusters. Hence, the size of the clusters inside the zeolites can be limited by the dimensions of their channels and cages. Zeolite-supported noble metal catalysts were extensively studied due to their wide application as catalysts in petroleum industry.Reduction of silver in zeolite hosts has been carried out by /-irradiation.The intermediate paramagnetic (charged) silver clusters formed in /-irradiated silver-exchanged zeolites have been studied by electron spin resonance (ESR)... 

The examples discussed above demonstrate the unique advantages of zeolitic hosts primarily stemming from highly dispersed exchange sites and the ligating effect of the framework on the cations. 

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