Ether models

Figure 2. Acidolysis of a bis-benzylic ether model compound...

Sousa LR, Larson JM (1977) Crown ether model systems for the study of photoexcited state response to geometrically oriented perturbers. The effect of alkali metal ions on emission from naphthalene derivatives. J Am Chem Soc 99 307-310... 

Meadows, E. S. De Wall, S. L. Barbour, L. J. Gokel, G. W. Alkali Metal Cation-Interactions Cbserved by using a Lariat Ether Model System. J. Am. Chem. Soc. 2001, 123, 3092-3107. 

Figure 3. Acidolysis of arylglycerol -aryl ether model compounds. Conditions 0.2M HCl in dioxane-water, 9 1, refluxed for 4 hours.

Section IV reviews our more recently developed 4D ether model [102-104], which is based on the premise of the existence of E. Rest mass is associated to a flow of primordial fluid (preons). This novel dynamic concept of mass solves at once several longstanding difficulties two of them are (1) the infinities associated with electric and gravitational fields and (2) the stability of orbits under Coulomb attraction. Indeed, there is a permanent flow of momentum across a particle (source) the momentum flux is occasionally tapped by interaction with a (test) particle. Such process does not change the total momentum flux available at the source hence, there is no loss of potential energy as in the conventional interpretation. The total momentum that crosses a source is, of course, infinite in an infinite time, but the source is always finite. 

The present compounds generally displayed a peak only in the 960 cm l region. One of the methoxy-substituted (x=5) and two of the ethoxy-substituted (x=5 and 8) poly(esters) were not LC, neither were two of the ether model compounds and several poly(ethers). As the cis/trans ratio was small and relatively independent of substituent, there are two likely reasons for the limitations on liquid-crystallinity ... 

The ester models, as stated above, were all LC, but two of the ether model compounds, the methoxy- and ethoxy-substituted derivatives, were not, despite the fact that each of these mesogens yielded some liquid-crystallinity in the poly(ether) form. Therefore it seems that the polymers in this system tend to be "more liquid crystalline" than the related small molecules. This hypothesis is supported by the fact that Memeger(H) found liquid crystallinity in allhydrocarbon polymers incorporating the distyrylbenzene mesogen, even in cases where the cis/trans ratio of the unsaturations was as large as 0.3, while Campbell and McDonald (10) noted that iodine isomerization to the all-trans form was essential for the observation of an LC phase in the small-molecule derivatives which they prepared. 

Another control experiment was run to further confirm the significance of the cation-pi interaction in these bibracchial lariat ether model complexes. In this case, a diaza-18-crown-6 derivative was prepared in which a 2-phenylethyl pi-donor sidearm was attached to one nitrogen and a 2-methoxyethyl sigma donor was attached to the other <2002CC1808>. The structure is illustrated as 14, above. The solid-state structure of the 14 KI complex showed the typical apical solvation of the ring bound cation. In this case, however, one apex was solvated in the pi-fashion (benzene) and the other by the oxygen sigma donor. 

Table 9 Relative Hydrolysis Rates of Lignin a- and P-Ether Models in 0.2 M HCl of Aqueous Dioxane at 50°C...

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