Methane encapsulation

The first copper(I) complex of tris(hydroxymethyl)phosphine ((760) tetrahedral) has been reported by Samuelson and co-workers. This group addressed the question of anion-controlled nuclearity and metal-metal distances in copper(I)-bis(diphenylphosphino)methane complexes, and in this endeavor they reported the structures of complexes (761) (Cu-Cu separation 3.005-3.128 A), (762) (Cu-Cu separation 3.165 A) and (763) (tetrahedral Cu-Cu 3.293 A). 6 They synthesized and provided structural evidence of oxy anion- encapsulated copper(I) complexes of this ligand. The complexes (764) (distorted tetrahedral Cu-Cu 3.143 A), (765) (distorted tetrahedral Cu-Cu 3.424A), (766) (distorted trigonal Cu-Cu 3.170A), and (767) (Cu-Cu 3.032-3.077A) were reported. They studied solid-state emission spectra of these complexes.567 During this pursuit they... 

Co2(CO)g has been used to obtain encapsulated cobalt clusters in Y-faujasite, which have been used as model catalysts for methane homologation [152]. The gas phase adsorption of Co2(CO)8 under N2 rendered predominately encaged Co4(CO)i2 species whereas Co,s(CO)iis was obtained when the impregnation of Co2(CO)8 was carried out under a CO/H2 atmosphere [152, 155], Samples were oxidized at 80°C, subsequently reduced at 400 °C and then structurally characterized by EXAFS. Clusters of two and three cobalt atoms were formed from encaged Co4(CO)i2 and COis(CO)iis, respectively. Higher methane conversion and selectivity to C2+ products in the CH4 homologation reaction have been obtained for the two atoms-size cluster sample the results were discussed using a DFT model [152]. 

Hydrate kinetics studies of methane mixed hydrate in sll hydrate are limited. This is mostly due to complication when working with mixture where the gas composition changes over time due to preferential guest dissolution in water and preferential encapsulation in the... 

Half a century later, the work of Carson and Katz (1942) provided a second reason for considering the dissociation condition of the hydrate equilibrium point (see Chapter 3, Figure 3.1b for more details). Their work clearly showed the solid solution behavior of hydrates formed by gas mixtures. This result meant that hydrate preferentially encapsulated propane from a methane + propane gas mixture, so that a closed gas volume was denuded of propane (or enriched in methane) as more hydrates formed. On the other hand, upon hydrate dissociation, when the last crystal melted the initial gas composition was regained, minus a very small amount to account for solubility in the liquid phase. 

When the BIIJ anion is encapsulated instead of CH4, the hypsochromic shifts A i str ( B11) increase to 180-200 cm-1. For encapsulated NHj, the Avstr(NH) shifts are smaller, 90-100 cm-1. The /str vibration in the charged clusters is significantly more intensive than in their methane analogue. 

A cavitand-porphyrin combination (22) has been synthesized O5ACIE3810, 06BCSJ1431, 06OL4275> and reported to have sufficient flexibility to facilitate moderate guest exchange rates for kinetic measurements the encapsulation of methane has been shown to have a half-life of 0.5 s <07JOC9448>. 

Compound 79, upon dimerisation, forms a larger capsule than that observed for 78 and is capable of encapsulating small guest species such as dichloro-methane and chloroform (from a C2D2C14 solution). The encapsulation was ob-... 

Carriers. The encapsulation of molecules into zeolite voids has been used to handle unpleasant chemicals, such as vulcanizing agents, and to carry CO2 in carbonated drinks. Other prospective uses are to store and transport methane and hydrogen. 

In comparison with the complex of [Yb(4)(CF3S03)2]CF3S03CH3CN, a more encapsulated ytterbium complex [Yb(5)(CF3S03)3] CH3CN [5] was synthesized by a template reaction of 2 equiv of N(CH2CH2NH2)3 with 10 equiv of bis(dimethylamino)methane in the presence of 1 equiv of ytterbium triflate. The most exciting feature of this complex is its... 

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