Electrostatic potential phenol

Nucleophilic atoms can also be identified by inspection of electrostatic potential maps. Reactive sites appeal as negative electrostatic potentials. Examine electrostatic potential maps for trimethylamine, methyl fluoride, and phenol. Identify the most nucleophilic atom in each molecule. Are these the same as you identified above using Lewis structures Are all sides of the nucleophilic atoms equally electron rich, or only particular regions ... 

Nucleophiles can also act as acids and bases, and this behavior substantially alters their nucleophilicity. At pH 5, trimethylamine exists mainly as its conjugate acid, trimethylammonium cation. First draw a Lewis structure, and then examine the electrostatic potential for trimethylammonium ion. On the basis of the map, which is the better nucleophile, the cation or the corresponding neutral amine At pH 12, phenol exists mainly as its conjugate base, phenoxide anion. First draw a Lewis structure (or series of Lewis structures), and then examine the electrostatic potential map for phenoxide anion. Which is the better nucleophile, phenoxide or phenol ... 

Phenol has different chemical properties from those of typical alcohols. Display the electrostatic potential map for phenol. Does this suggest that phenol is likely to be a stronger or weaker acid than any of the compounds discussed above Compare the electrostatic potential map for 4-nitrophenol to that for phenol. What effect does substitution by nitro have on acid strength Explain your result by considering charge delocalization in the conjugate base. Draw all reasonable Lewis structures for phenoxide anion and for 4-nitrophenoxide anion. Which is more delocalized Is this consistent with experimental pKa s ... 

Figure 17.1 Hydrogen-bonding in alcohols and phenols. A weak attraction between a positively polarized OH hydrogen and a negatively polarized oxygen holds molecules together. The electrostatic potential map of methanol shows the positively polarized O-H hydrogen (blue) and the negatively polarized oxygen (red).

Chlorobenzene, electrostatic potential map of, 565 13C NMR absorptions of, 536 phenol from, 575 p-Chlorobenzoic acid, pKa of, 760... 

The graphic that opened this chapter is a molecular model of phenol that shows its planar structure and electrostatic potential. 

TABLE 6. Solute hydrogen-bond acidity parameters84 (a ) and surface electrostatic potential maxima75 (FS max) for some alcohols and phenols... 

Use SpartanView to compare the electrostatic potential maps of the anions of phenol, 4-cyanophenol, and 4-cyanomethyIpheool. Order them according to the amount of negative character on oxygen, and tell which phenol is most acidic. 

Ma, Y.G., Gross, K.C., Hollingsworth, C.A., Seybold, P.G., Murray, J.S. Relationships between aqueous acidities and computed surface-electrostatic potentials and local ionization energies of substituted phenols and benzoic acids. J. Mol. Model. 2004,10(4), 235-9. 

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