Space-filling models ethylene

Four models of ethylene The dash-wedge, ball-and-stick, and space-filling models show that the four atoms attached to a carbon-carbon double bond lie in a single plane. The electrostatic potential map shows the electron density (red) above and below the plane that passes through the carbon and hydrogen nuclei. 

Space-filling model of ethylene glycol, the main constituent of automobile antifreeze... 

Top. Pi bonding forces the two CH2 groups in ethylene to bond so as to give a planar structure. Boffom. A space-filling model shows the planar structure of the molecule. 

Figure 4a shows the space filling model viewed from the hydrophobic side of CF6. It is clear that the oxygen atoms are all hidden by the ethylene groups in the 18-crown-6 core, and the inner diameter of the macrocycle is around 1.5 A (as compared to 2.6 A in 18-crown-6 [29]). Consequently, any solute interaction with the six oxygen atoms on the 18-crown-6 moiety from the hydrophobic side of CF6 is not likely. On the hydrophilic side, 3-OH groups from the three inward-inclined fructofuranose units (the 03(i) groups in Fig. 2) are hydrogen bonding with each other and so, effectively blocking the access to the macrocycle cavity from this side (Fig. 4b). Consequently, the 18-crown-6 core of the native CF6 in cavity is effectively folded inside the molecule and is relatively inaccessible from both sides.

Use of this tandem method resulted in a model ethylene/CO copolymer (Figure 2, polymer 2) that had a Tm (134 °C) close to that observed in our linear ADMET polyethylene (Figure 4, second entry) [17]. Since carbonyl and methylene groups have similar space filling characteristics, the CO functional group may be expected to cause very little disruption of the lamellar crystal lattice of polyethylene. 

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